yaxpeax-x86 decodes in 32-bit mode now

1 files changed, 6453 insertions, 1 deletions

diff --git a/src/protected_mode/mod.rs b/src/protected_mode/mod.rs
index de7ec27..ac7968c 100644
--- a/src/protected_mode/mod.rs
+++ b/src/protected_mode/mod.rs
@@ -1 +1,6453 @@
-pub struct Arch {}
+mod vex;
+mod display;
+
+use core::hint::unreachable_unchecked;
+
+use yaxpeax_arch::{Decoder, LengthedInstruction};
+
+#[cfg(feature="use-serde")]
+#[derive(Copy, Clone, Debug, PartialOrd, Ord, Eq, PartialEq, Serialize, Deserialize)]
+pub struct RegSpec {
+    pub num: u8,
+    pub bank: RegisterBank
+}
+#[cfg(not(feature="use-serde"))]
+#[derive(Copy, Clone, Debug, PartialOrd, Ord, Eq, PartialEq)]
+pub struct RegSpec {
+    pub num: u8,
+    pub bank: RegisterBank
+}
+
+use core::hash::Hash;
+use core::hash::Hasher;
+impl Hash for RegSpec {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        let code = ((self.bank as u16) << 8) | (self.num as u16);
+        code.hash(state);
+    }
+}
+
+// This is only to select alternate opcode maps for the 0f escape byte.
+// This often could be treated as a size prefix but in some cases selects
+// an entirely different operation.
+#[derive(Debug)]
+enum OpcodeMap {
+    Map66,
+    MapF2,
+    MapF3,
+}
+
+#[derive(Debug)]
+pub enum ConditionCode {
+    O,
+    NO,
+    B,
+    AE,
+    Z,
+    NZ,
+    A,
+    BE,
+    S,
+    NS,
+    P,
+    NP,
+    L,
+    GE,
+    G,
+    LE,
+}
+
+#[allow(non_snake_case)]
+impl RegSpec {
+    pub fn name(&self) -> &'static str {
+        display::regspec_label(self)
+    }
+
+    #[inline]
+    fn from_parts(num: u8, bank: RegisterBank) -> RegSpec {
+        RegSpec {
+            num: num,
+            bank: bank
+        }
+    }
+
+    #[inline]
+    fn gp_from_parts(num: u8, width: u8) -> RegSpec {
+        RegSpec {
+            num: num,
+            bank: width_to_gp_reg_bank(width)
+        }
+    }
+
+    #[inline]
+    pub fn eip() -> RegSpec {
+        RegSpec {
+            num: 0,
+            bank: RegisterBank::EIP
+        }
+    }
+
+    #[inline]
+    pub fn eflags() -> RegSpec {
+        RegSpec {
+            num: 0,
+            bank: RegisterBank::EFlags
+        }
+    }
+
+    #[inline]
+    pub fn bp() -> RegSpec {
+        RegSpec {
+            num: 5,
+            bank: RegisterBank::W
+        }
+    }
+
+    #[inline]
+    pub fn ebp() -> RegSpec {
+        RegSpec {
+            num: 5,
+            bank: RegisterBank::D
+        }
+    }
+
+    #[inline]
+    pub fn esp() -> RegSpec {
+        RegSpec {
+            num: 4,
+            bank: RegisterBank::D
+        }
+    }
+
+    #[inline]
+    pub fn fs() -> RegSpec {
+        RegSpec { bank: RegisterBank::S, num: 3 }
+    }
+
+    #[inline]
+    pub fn gs() -> RegSpec {
+        RegSpec { bank: RegisterBank::S, num: 4 }
+    }
+
+    #[inline]
+    pub fn eax() -> RegSpec {
+        RegSpec { bank: RegisterBank::D, num: 0 }
+    }
+
+    #[inline]
+    pub fn ecx() -> RegSpec {
+        RegSpec { bank: RegisterBank::D, num: 1 }
+    }
+
+    #[inline]
+    pub fn edx() -> RegSpec {
+        RegSpec { bank: RegisterBank::D, num: 2 }
+    }
+
+    #[inline]
+    pub fn bx() -> RegSpec {
+        RegSpec { bank: RegisterBank::W, num: 3 }
+    }
+
+    #[inline]
+    pub fn ebx() -> RegSpec {
+        RegSpec { bank: RegisterBank::D, num: 3 }
+    }
+
+    #[inline]
+    pub fn si() -> RegSpec {
+        RegSpec { bank: RegisterBank::W, num: 6 }
+    }
+
+    #[inline]
+    pub fn esi() -> RegSpec {
+        RegSpec { bank: RegisterBank::D, num: 6 }
+    }
+
+    #[inline]
+    pub fn di() -> RegSpec {
+        RegSpec { bank: RegisterBank::W, num: 7 }
+    }
+
+    #[inline]
+    pub fn edi() -> RegSpec {
+        RegSpec { bank: RegisterBank::D, num: 7 }
+    }
+
+    #[inline]
+    pub fn ax() -> RegSpec {
+        RegSpec { bank: RegisterBank::W, num: 0 }
+    }
+
+    #[inline]
+    pub fn dx() -> RegSpec {
+        RegSpec { bank: RegisterBank::W, num: 2 }
+    }
+
+    #[inline]
+    pub fn al() -> RegSpec {
+        RegSpec { bank: RegisterBank::B, num: 0 }
+    }
+
+    #[inline]
+    pub fn cl() -> RegSpec {
+        RegSpec { bank: RegisterBank::B, num: 1 }
+    }
+}
+
+#[allow(non_camel_case_types)]
+#[allow(dead_code)]
+enum SizeCode {
+    b,
+    vd,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Operand {
+    ImmediateI8(i8),
+    ImmediateU8(u8),
+    ImmediateI16(i16),
+    ImmediateU16(u16),
+    ImmediateU32(u32),
+    ImmediateI32(i32),
+    Register(RegSpec),
+    DisplacementU32(u32),
+    DisplacementU16(u16),
+    RegDeref(RegSpec),
+    RegDisp(RegSpec, i32),
+    RegScale(RegSpec, u8),
+    RegIndexBase(RegSpec, RegSpec),
+    RegIndexBaseDisp(RegSpec, RegSpec, i32),
+    RegScaleDisp(RegSpec, u8, i32),
+    RegIndexBaseScale(RegSpec, RegSpec, u8),
+    RegIndexBaseScaleDisp(RegSpec, RegSpec, u8, i32),
+    Nothing,
+}
+
+impl OperandSpec {
+    pub fn is_memory(&self) -> bool {
+        match self {
+            OperandSpec::DispU32 |
+            OperandSpec::DispU16 |
+            OperandSpec::Deref |
+            OperandSpec::Deref_esi |
+            OperandSpec::Deref_edi |
+            OperandSpec::RegDisp |
+            OperandSpec::RegScale |
+            OperandSpec::RegIndexBase |
+            OperandSpec::RegIndexBaseDisp |
+            OperandSpec::RegScaleDisp |
+            OperandSpec::RegIndexBaseScale |
+            OperandSpec::RegIndexBaseScaleDisp => {
+                true
+            },
+            OperandSpec::ImmI8 |
+            OperandSpec::ImmI16 |
+            OperandSpec::ImmI32 |
+            OperandSpec::ImmU8 |
+            OperandSpec::ImmU16 |
+            OperandSpec::ImmU32 |
+            OperandSpec::RegRRR |
+            OperandSpec::RegMMM |
+            OperandSpec::RegVex |
+            OperandSpec::AL |
+            OperandSpec::CL |
+            OperandSpec::Nothing => {
+                false
+            }
+        }
+    }
+}
+impl Operand {
+    fn from_spec(inst: &Instruction, spec: OperandSpec) -> Operand {
+        match spec {
+            OperandSpec::Nothing => {
+                Operand::Nothing
+            }
+            // the register in modrm_rrr
+            OperandSpec::RegRRR => {
+                Operand::Register(inst.modrm_rrr)
+            }
+            // the register in modrm_mmm (eg modrm mod bits were 11)
+            OperandSpec::RegMMM => {
+                Operand::Register(inst.modrm_mmm)
+            }
+            OperandSpec::RegVex => {
+                Operand::Register(inst.vex_reg)
+            }
+            OperandSpec::AL => {
+                Operand::Register(RegSpec::al())
+            }
+            OperandSpec::CL => {
+                Operand::Register(RegSpec::cl())
+            }
+            OperandSpec::ImmI8 => Operand::ImmediateI8(inst.imm as i8),
+            OperandSpec::ImmU8 => Operand::ImmediateU8(inst.imm as u8),
+            OperandSpec::ImmI16 => Operand::ImmediateI16(inst.imm as i16),
+            OperandSpec::ImmU16 => Operand::ImmediateU16(inst.imm as u16),
+            OperandSpec::ImmI32 => Operand::ImmediateI32(inst.imm as i32),
+            OperandSpec::ImmU32 => Operand::ImmediateU32(inst.imm as u32),
+            OperandSpec::DispU32 => Operand::DisplacementU32(inst.disp),
+            OperandSpec::DispU16 => Operand::DisplacementU16(inst.disp as u16),
+            OperandSpec::Deref => {
+                Operand::RegDeref(inst.modrm_mmm)
+            }
+            OperandSpec::Deref_esi => {
+                Operand::RegDeref(RegSpec::esi())
+            }
+            OperandSpec::Deref_edi => {
+                Operand::RegDeref(RegSpec::edi())
+            }
+            OperandSpec::RegDisp => {
+                Operand::RegDisp(inst.modrm_mmm, inst.disp as i32)
+            }
+            OperandSpec::RegScale => {
+                Operand::RegScale(inst.sib_index, inst.scale)
+            }
+            OperandSpec::RegIndexBase => {
+                Operand::RegIndexBase(inst.modrm_mmm, inst.sib_index)
+            }
+            OperandSpec::RegIndexBaseDisp => {
+                Operand::RegIndexBaseDisp(inst.modrm_mmm, inst.sib_index, inst.disp as i32)
+            }
+            OperandSpec::RegScaleDisp => {
+                Operand::RegScaleDisp(inst.sib_index, inst.scale, inst.disp as i32)
+            }
+            OperandSpec::RegIndexBaseScale => {
+                Operand::RegIndexBaseScale(inst.modrm_mmm, inst.sib_index, inst.scale)
+            }
+            OperandSpec::RegIndexBaseScaleDisp => {
+                Operand::RegIndexBaseScaleDisp(inst.modrm_mmm, inst.sib_index, inst.scale, inst.disp as i32)
+            }
+        }
+    }
+    pub fn is_memory(&self) -> bool {
+        match self {
+            Operand::DisplacementU16(_) |
+            Operand::DisplacementU32(_) |
+            Operand::RegDeref(_) |
+            Operand::RegDisp(_, _) |
+            Operand::RegScale(_, _) |
+            Operand::RegIndexBase(_, _) |
+            Operand::RegIndexBaseDisp(_, _, _) |
+            Operand::RegScaleDisp(_, _, _) |
+            Operand::RegIndexBaseScale(_, _, _) |
+            Operand::RegIndexBaseScaleDisp(_, _, _, _) => {
+                true
+            },
+            Operand::ImmediateI8(_) |
+            Operand::ImmediateU8(_) |
+            Operand::ImmediateI16(_) |
+            Operand::ImmediateU16(_) |
+            Operand::ImmediateU32(_) |
+            Operand::ImmediateI32(_) |
+            Operand::Register(_) |
+            Operand::Nothing => {
+                false
+            }
+        }
+    }
+}
+
+#[test]
+fn operand_size() {
+    assert_eq!(core::mem::size_of::<OperandSpec>(), 1);
+    assert_eq!(core::mem::size_of::<RegSpec>(), 2);
+    // assert_eq!(core::mem::size_of::<Prefixes>(), 4);
+    // assert_eq!(core::mem::size_of::<Instruction>(), 40);
+}
+
+#[allow(non_camel_case_types)]
+#[cfg(feature="use-serde")]
+#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Serialize, Deserialize)]
+pub enum RegisterBank {
+    D, W, B, // Dword, Word, Byte
+    CR, DR, S, EIP, EFlags,  // Control reg, Debug reg, Selector, ...
+    X, Y, Z,    // XMM, YMM, ZMM
+    ST, MM,     // ST, MM regs (x87, mmx)
+    K, // AVX512 mask registers
+}
+#[allow(non_camel_case_types)]
+#[cfg(not(feature="use-serde"))]
+#[derive(Copy, Clone, Debug, Ord, PartialOrd, Eq, PartialEq, Hash)]
+pub enum RegisterBank {
+    D, W, B, // Dword, Word, Byte
+    CR, DR, S, EIP, EFlags,  // Control reg, Debug reg, Selector, ...
+    X, Y, Z,    // XMM, YMM, ZMM
+    ST, MM,     // ST, MM regs (x87, mmx)
+    K, // AVX512 mask registers
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub enum Segment {
+    DS = 0, CS, ES, FS, GS, SS
+}
+
+const BMI1: [Opcode; 6] = [
+    Opcode::ANDN,
+    Opcode::BEXTR,
+    Opcode::BLSI,
+    Opcode::BLSMSK,
+    Opcode::BLSR,
+    Opcode::TZCNT,
+];
+
+// TODO:
+// PTWRITE
+// RDFSBASE
+// RDGSBASE
+// WRFSBASE
+// WRGSBASE
+// TPAUSE
+// UMONITOR
+// UMWAIT
+// CLFLUSHOPT
+// CLWB
+#[allow(non_camel_case_types)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum Opcode {
+    ADD = 1,
+    OR = 2,
+    ADC = 3,
+    SBB = 4,
+    AND = 5,
+    XOR = 6,
+    SUB = 7,
+    CMP = 8,
+    Invalid,
+    XADD,
+    BT,
+    BTS,
+    BTC,
+    BTR,
+    BSF,
+    BSR,
+    TZCNT,
+    MOVSS,
+    ADDSS,
+    SUBSS,
+    MULSS,
+    DIVSS,
+    MINSS,
+    MAXSS,
+    SQRTSS,
+    MOVSD,
+    SQRTSD,
+    ADDSD,
+    SUBSD,
+    MULSD,
+    DIVSD,
+    MINSD,
+    MAXSD,
+    MOVSLDUP,
+    MOVSHDUP,
+    MOVDDUP,
+    HADDPS,
+    HSUBPS,
+    ADDSUBPD,
+    ADDSUBPS,
+    CVTSI2SS,
+    CVTSI2SD,
+    CVTTSD2SI,
+    CVTTPS2DQ,
+    CVTPD2DQ,
+    CVTPD2PS,
+    CVTPS2DQ,
+    CVTSD2SI,
+    CVTSD2SS,
+    CVTTSS2SI,
+    CVTSS2SI,
+    CVTSS2SD,
+    CVTDQ2PD,
+    LDDQU,
+    MOVSX_b,
+    MOVSX_w,
+    MOVZX_b,
+    MOVZX_w,
+    MOVSX,
+    ARPL,
+    SAR,
+    SAL,
+    SHR,
+    SHRD,
+    SHL,
+    RCR,
+    RCL,
+    ROR,
+    ROL,
+    INC,
+    DEC,
+    HLT,
+    CALL,
+    CALLF,
+    JMP,
+    JMPF,
+    PUSH,
+    POP,
+    LEA,
+    NOP,
+    PREFETCHNTA,
+    PREFETCH0,
+    PREFETCH1,
+    PREFETCH2,
+    XCHG,
+    POPF,
+    INT,
+    INTO,
+    IRET,
+    RETF,
+    ENTER,
+    LEAVE,
+    MOV,
+    RETURN,
+    PUSHF,
+    WAIT,
+    CBW,
+    CWDE,
+    CDQE,
+    CBD,
+    CDQ,
+    CQO,
+    LODS,
+    STOS,
+    LAHF,
+    SAHF,
+    CMPS,
+    SCAS,
+    MOVS,
+    TEST,
+    INS,
+    IN,
+    OUTS,
+    OUT,
+    IMUL,
+    JO,
+    JNO,
+    JB,
+    JNB,
+    JZ,
+    JNZ,
+    JA,
+    JNA,
+    JS,
+    JNS,
+    JP,
+    JNP,
+    JL,
+    JGE,
+    JLE,
+    JG,
+    CMOVA,
+    CMOVB,
+    CMOVG,
+    CMOVGE,
+    CMOVL,
+    CMOVLE,
+    CMOVNA,
+    CMOVNB,
+    CMOVNO,
+    CMOVNP,
+    CMOVNS,
+    CMOVNZ,
+    CMOVO,
+    CMOVP,
+    CMOVS,
+    CMOVZ,
+    DIV,
+    IDIV,
+    MUL,
+    NEG,
+    NOT,
+    CMPXCHG,
+    SETO,
+    SETNO,
+    SETB,
+    SETAE,
+    SETZ,
+    SETNZ,
+    SETBE,
+    SETA,
+    SETS,
+    SETNS,
+    SETP,
+    SETNP,
+    SETL,
+    SETGE,
+    SETLE,
+    SETG,
+    CPUID,
+    UD2,
+    WBINVD,
+    INVD,
+    SYSRET,
+    CLTS,
+    SYSCALL,
+    LSL,
+    LAR,
+    LES,
+    LDS,
+    SGDT,
+    SIDT,
+    LGDT,
+    LIDT,
+    SMSW,
+    LMSW,
+    SWAPGS,
+    RDTSCP,
+    INVLPG,
+    FXSAVE,
+    FXRSTOR,
+    LDMXCSR,
+    STMXCSR,
+    XSAVE,
+    XRSTOR,
+    XSAVEOPT,
+    LFENCE,
+    MFENCE,
+    SFENCE,
+    CLFLUSH,
+    WRMSR,
+    RDTSC,
+    RDMSR,
+    RDPMC,
+    SLDT,
+    STR,
+    LLDT,
+    LTR,
+    VERR,
+    VERW,
+    CLC,
+    STC,
+    CLI,
+    STI,
+    CLD,
+    STD,
+    JMPE,
+    POPCNT,
+    MOVDQU,
+    MOVDQA,
+    MOVQ,
+    CMPSS,
+    CMPSD,
+    UNPCKLPS,
+    UNPCKLPD,
+    UNPCKHPS,
+    UNPCKHPD,
+    PSHUFHW,
+    PSHUFLW,
+    MOVUPS,
+    MOVQ2DQ,
+    MOVDQ2Q,
+    RSQRTSS,
+    RCPSS,
+
+    ANDN,
+    BEXTR,
+    BLSI,
+    BLSMSK,
+    BLSR,
+    VMCLEAR,
+    VMXON,
+    VMCALL,
+    VMLAUNCH,
+    VMRESUME,
+    VMXOFF,
+    MONITOR,
+    MWAIT,
+    CLAC,
+    STAC,
+    ENCLS,
+    ENCLV,
+    XGETBV,
+    XSETBV,
+    VMFUNC,
+    XEND,
+    XTEST,
+    ENCLU,
+    RDPKRU,
+    WRPKRU,
+
+    ADDPS,
+    ADDPD,
+    ANDNPS,
+    ANDNPD,
+    ANDPS,
+    ANDPD,
+    BSWAP,
+    CMPPD,
+    CMPPS,
+    COMISD,
+    COMISS,
+    CVTDQ2PS,
+    CVTPI2PS,
+    CVTPI2PD,
+    CVTPS2PD,
+    CVTPS2PI,
+    CVTPD2PI,
+    CVTTPS2PI,
+    CVTTPD2PI,
+    CVTTPD2DQ,
+    DIVPS,
+    DIVPD,
+    EMMS,
+    GETSEC,
+    LFS,
+    LGS,
+    LSS,
+    MASKMOVQ,
+    MASKMOVDQU,
+    MAXPS,
+    MAXPD,
+    MINPS,
+    MINPD,
+    MOVAPS,
+    MOVAPD,
+    MOVD,
+    MOVLPS,
+    MOVLPD,
+    MOVHPS,
+    MOVHPD,
+    MOVLHPS,
+    MOVHLPS,
+    MOVUPD,
+    MOVMSKPS,
+    MOVMSKPD,
+    MOVNTI,
+    MOVNTPS,
+    MOVNTPD,
+    MOVNTQ,
+    MOVNTDQ,
+    MULPS,
+    MULPD,
+    ORPS,
+    ORPD,
+    PACKSSDW,
+    PACKSSWB,
+    PACKUSWB,
+    PADDB,
+    PADDD,
+    PADDQ,
+    PADDSB,
+    PADDSW,
+    PADDUSB,
+    PADDUSW,
+    PADDW,
+    PAND,
+    PANDN,
+    PAVGB,
+    PAVGW,
+    PCMPEQB,
+    PCMPEQD,
+    PCMPEQW,
+    PCMPGTB,
+    PCMPGTD,
+    PCMPGTW,
+    PEXTRW,
+    PINSRW,
+    PMADDWD,
+    PMAXSW,
+    PMAXUB,
+    PMINSW,
+    PMINUB,
+    PMOVMSKB,
+    PMULHUW,
+    PMULHW,
+    PMULLW,
+    PMULUDQ,
+    POR,
+    PSADBW,
+    PSHUFW,
+    PSHUFD,
+    PSLLD,
+    PSLLDQ,
+    PSLLQ,
+    PSLLW,
+    PSRAD,
+    PSRAW,
+    PSRLD,
+    PSRLDQ,
+    PSRLQ,
+    PSRLW,
+    PSUBB,
+    PSUBD,
+    PSUBQ,
+    PSUBSB,
+    PSUBSW,
+    PSUBUSB,
+    PSUBUSW,
+    PSUBW,
+    PUNPCKHBW,
+    PUNPCKHDQ,
+    PUNPCKHWD,
+    PUNPCKLBW,
+    PUNPCKLDQ,
+    PUNPCKLWD,
+    PUNPCKLQDQ,
+    PUNPCKHQDQ,
+    PXOR,
+    RCPPS,
+    RSM,
+    RSQRTPS,
+    SHLD,
+    SHUFPD,
+    SHUFPS,
+    SLHD,
+    SQRTPS,
+    SQRTPD,
+    SUBPS,
+    SUBPD,
+    SYSENTER,
+    SYSEXIT,
+    UCOMISD,
+    UCOMISS,
+    UD2E,
+    VMREAD,
+    VMWRITE,
+    XORPS,
+    XORPD,
+
+    VMOVDDUP,
+    VPSHUFLW,
+    VHADDPS,
+    VHSUBPS,
+    VADDSUBPS,
+    VCVTPD2DQ,
+    VLDDQU,
+
+    VCOMISD,
+    VCOMISS,
+    VUCOMISD,
+    VUCOMISS,
+    VADDPD,
+    VADDPS,
+    VADDSD,
+    VADDSS,
+    VADDSUBPD,
+    VAESDEC,
+    VAESDECLAST,
+    VAESENC,
+    VAESENCLAST,
+    VAESIMC,
+    VAESKEYGENASSIST,
+    VBLENDPD,
+    VBLENDPS,
+    VBLENDVPD,
+    VBLENDVPS,
+    VBROADCASTF128,
+    VBROADCASTI128,
+    VBROADCASTSD,
+    VBROADCASTSS,
+    VCMPSD,
+    VCMPSS,
+    VCMPPD,
+    VCMPPS,
+    VCVTDQ2PD,
+    VCVTDQ2PS,
+    VCVTPD2PS,
+    VCVTPH2PS,
+    VCVTPS2DQ,
+    VCVTPS2PD,
+    VCVTSS2SD,
+    VCVTSI2SS,
+    VCVTSI2SD,
+    VCVTSD2SI,
+    VCVTSD2SS,
+    VCVTPS2PH,
+    VCVTSS2SI,
+    VCVTTPD2DQ,
+    VCVTTPS2DQ,
+    VCVTTSS2SI,
+    VCVTTSD2SI,
+    VDIVPD,
+    VDIVPS,
+    VDIVSD,
+    VDIVSS,
+    VDPPD,
+    VDPPS,
+    VEXTRACTF128,
+    VEXTRACTI128,
+    VEXTRACTPS,
+    VFMADD132PD,
+    VFMADD132PS,
+    VFMADD132SD,
+    VFMADD132SS,
+    VFMADD213PD,
+    VFMADD213PS,
+    VFMADD213SD,
+    VFMADD213SS,
+    VFMADD231PD,
+    VFMADD231PS,
+    VFMADD231SD,
+    VFMADD231SS,
+    VFMADDSUB132PD,
+    VFMADDSUB132PS,
+    VFMADDSUB213PD,
+    VFMADDSUB213PS,
+    VFMADDSUB231PD,
+    VFMADDSUB231PS,
+    VFMSUB132PD,
+    VFMSUB132PS,
+    VFMSUB132SD,
+    VFMSUB132SS,
+    VFMSUB213PD,
+    VFMSUB213PS,
+    VFMSUB213SD,
+    VFMSUB213SS,
+    VFMSUB231PD,
+    VFMSUB231PS,
+    VFMSUB231SD,
+    VFMSUB231SS,
+    VFMSUBADD132PD,
+    VFMSUBADD132PS,
+    VFMSUBADD213PD,
+    VFMSUBADD213PS,
+    VFMSUBADD231PD,
+    VFMSUBADD231PS,
+    VFNMADD132PD,
+    VFNMADD132PS,
+    VFNMADD132SD,
+    VFNMADD132SS,
+    VFNMADD213PD,
+    VFNMADD213PS,
+    VFNMADD213SD,
+    VFNMADD213SS,
+    VFNMADD231PD,
+    VFNMADD231PS,
+    VFNMADD231SD,
+    VFNMADD231SS,
+    VFNMSUB132PD,
+    VFNMSUB132PS,
+    VFNMSUB132SD,
+    VFNMSUB132SS,
+    VFNMSUB213PD,
+    VFNMSUB213PS,
+    VFNMSUB213SD,
+    VFNMSUB213SS,
+    VFNMSUB231PD,
+    VFNMSUB231PS,
+    VFNMSUB231SD,
+    VFNMSUB231SS,
+    VGATHERDPD,
+    VGATHERDPS,
+    VGATHERQPD,
+    VGATHERQPS,
+    VHADDPD,
+    VHSUBPD,
+    VINSERTF128,
+    VINSERTI128,
+    VINSERTPS,
+    VMASKMOVDQU,
+    VMASKMOVPD,
+    VMASKMOVPS,
+    VMAXPD,
+    VMAXPS,
+    VMAXSD,
+    VMAXSS,
+    VMINPD,
+    VMINPS,
+    VMINSD,
+    VMINSS,
+    VMOVAPD,
+    VMOVAPS,
+    VMOVD,
+    VMOVDQA,
+    VMOVDQU,
+    VMOVHLPS,
+    VMOVHPD,
+    VMOVHPS,
+    VMOVLHPS,
+    VMOVLPD,
+    VMOVLPS,
+    VMOVMSKPD,
+    VMOVMSKPS,
+    VMOVNTDQ,
+    VMOVNTDQA,
+    VMOVNTPD,
+    VMOVNTPS,
+    VMOVQ,
+    VMOVSS,
+    VMOVSD,
+    VMOVSHDUP,
+    VMOVSLDUP,
+    VMOVUPD,
+    VMOVUPS,
+    VMPSADBW,
+    VMULPD,
+    VMULPS,
+    VMULSD,
+    VMULSS,
+    VPABSB,
+    VPABSD,
+    VPABSW,
+    VPACKSSDW,
+    VPACKSSWB,
+    VPACKUSWB,
+    VPADDB,
+    VPADDD,
+    VPADDQ,
+    VPADDSB,
+    VPADDSW,
+    VPADDUSB,
+    VPADDUSW,
+    VPADDW,
+    VPALIGNR,
+    VPAND,
+    VPANDN,
+    VPAVGB,
+    VPAVGW,
+    VPBLENDD,
+    VPBLENDVB,
+    VPBLENDW,
+    VPBROADCASTB,
+    VPBROADCASTD,
+    VPBROADCASTQ,
+    VPBROADCASTW,
+    VPCLMULQDQ,
+    VPCMPEQB,
+    VPCMPEQD,
+    VPCMPEQQ,
+    VPCMPEQW,
+    VPCMPGTB,
+    VPCMPGTD,
+    VPCMPGTQ,
+    VPCMPGTW,
+    VPCMPISTRI,
+    VPCMPISTRM,
+    VPERM2F128,
+    VPERM2I128,
+    VPERMD,
+    VPERMILPD,
+    VPERMILPS,
+    VPERMPD,
+    VPERMPS,
+    VPERMQ,
+    VPEXTRB,
+    VPEXTRD,
+    VPEXTRQ,
+    VPEXTRW,
+    VPGATHERDD,
+    VPGATHERDQ,
+    VPGATHERQD,
+    VPGATHERQQ,
+    VPHADDD,
+    VPHADDSW,
+    VPHADDW,
+    VPHADDUBSW,
+    VPHMINPOSUW,
+    VPHSUBD,
+    VPHSUBSW,
+    VPHSUBW,
+    VPINSRB,
+    VPINSRD,
+    VPINSRQ,
+    VPINSRW,
+    VPMADDWD,
+    VPMASKMOVD,
+    VPMASKMOVQ,
+    VPMAXSB,
+    VPMAXSD,
+    VPMAXSW,
+    VPMAXUD,
+    VPMINSD,
+    VPMINUD,
+    VPMOVMSKB,
+    VPMOVSXBD,
+    VPMOVSXBQ,
+    VPMOVSXBW,
+    VPMOVSXDQ,
+    VPMOVSXWD,
+    VPMOVSXWQ,
+    VPMOVZXBD,
+    VPMOVZXBQ,
+    VPMOVZXBW,
+    VPMOVZXDQ,
+    VPMOVZXWD,
+    VPMOVZXWQ,
+    VPMULDQ,
+    VPMULHRSW,
+    VPMULHUW,
+    VPMULHW,
+    VPMULLD,
+    VPMULLW,
+    VPMULUDQ,
+    VPOR,
+    VPSADBW,
+    VPSHUFB,
+    VPSHUFD,
+    VPSIGNB,
+    VPSIGND,
+    VPSIGNW,
+    VPSLLD,
+    VPSLLDQ,
+    VPSLLQ,
+    VPSLLVD,
+    VPSLLVQ,
+    VPSLLW,
+    VPSRAD,
+    VPSRAVD,
+    VPSRAW,
+    VPSRLD,
+    VPSRLDQ,
+    VPSRLQ,
+    VPSRLVD,
+    VPSRLVQ,
+    VPSRLW,
+    VPSUBB,
+    VPSUBD,
+    VPSUBQ,
+    VPSUBSB,
+    VPSUBSW,
+    VPSUBUSB,
+    VPSUBUSW,
+    VPSUBW,
+    VPTEST,
+    VPUNPCKHBW,
+    VPUNPCKHDQ,
+    VPUNPCKHQDQ,
+    VPUNPCKHWD,
+    VPUNPCKLBW,
+    VPUNPCKLDQ,
+    VPUNPCKLQDQ,
+    VPUNPCKLWD,
+    VPXOR,
+    VRCPPS,
+    VROUNDPD,
+    VROUNDPS,
+    VROUNDSD,
+    VROUNDSS,
+    VRSQRTPS,
+    VRSQRTSS,
+    VRCPSS,
+    VSHUFPD,
+    VSHUFPS,
+    VSQRTPD,
+    VSQRTPS,
+    VSQRTSS,
+    VSQRTSD,
+    VSUBPD,
+    VSUBPS,
+    VSUBSD,
+    VSUBSS,
+    VTESTPD,
+    VTESTPS,
+    VUNPCKHPD,
+    VUNPCKHPS,
+    VUNPCKLPD,
+    VUNPCKLPS,
+    VXORPD,
+    VXORPS,
+    VZEROUPPER,
+
+    PCLMULQDQ,
+    AESKEYGENASSIST,
+    AESIMC,
+    AESENC,
+    AESENCLAST,
+    AESDEC,
+    AESDECLAST,
+    PCMPGTQ,
+    PCMPISTRM,
+    PCMPISTRI,
+    PCMPESTRI,
+    PACKUSDW,
+    PCMPESTRM,
+    PCMPEQQ,
+    PTEST,
+    PHMINPOSUW,
+    MPSADBW,
+    PMOVZXDQ,
+    PMOVSXDQ,
+    PMOVZXBD,
+    PMOVSXBD,
+    PMOVZXWQ,
+    PMOVSXWQ,
+    PMOVZXBQ,
+    PMOVSXBQ,
+    PMOVSXWD,
+    PMOVZXWD,
+    PEXTRQ,
+    PEXTRB,
+    PMOVSXBW,
+    PMOVZXBW,
+    PINSRQ,
+    PINSRD,
+    PINSRB,
+    EXTRACTPS,
+    INSERTPS,
+    ROUNDSS,
+    ROUNDSD,
+    ROUNDPS,
+    ROUNDPD,
+    PMAXSB,
+    PMAXUW,
+    PMAXUD,
+    PMINSD,
+    PMINSB,
+    PMINUD,
+    PMINUW,
+    BLENDW,
+    BLENDDVB,
+    BLENDVPS,
+    BLENDVPD,
+    BLENDPS,
+    BLENDPD,
+    PMULDQ,
+    MOVNTDQA,
+    PMULLD,
+    PALIGNR,
+    PSIGNW,
+    PSIGND,
+    PSIGNB,
+    PSHUFB,
+    PMULHRSU,
+    PMADDUBSW,
+    PABSD,
+    PABSW,
+    PABSB,
+    PHSUBSW,
+    PHSUBW,
+    PHSUBD,
+    PHADDD,
+    PHADDSW,
+    PHADDW,
+    HSUBPD,
+    HADDPD,
+}
+
+#[derive(Debug)]
+pub struct Instruction {
+    pub prefixes: Prefixes,
+    modrm_rrr: RegSpec,
+    modrm_mmm: RegSpec, // doubles as sib_base
+    sib_index: RegSpec,
+    vex_reg: RegSpec,
+    scale: u8,
+    length: u8,
+    operand_count: u8,
+    operands: [OperandSpec; 4],
+    imm: u32,
+    disp: u32,
+    pub opcode: Opcode,
+}
+
+impl yaxpeax_arch::Instruction for Instruction {
+    fn well_defined(&self) -> bool {
+        // TODO: this is incorrect!
+        true
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub enum DecodeError {
+    ExhaustedInput,
+    InvalidOpcode,
+    InvalidOperand,
+    InvalidPrefixes,
+    TooLong,
+    IncompleteDecoder,
+}
+
+impl yaxpeax_arch::DecodeError for DecodeError {
+    fn data_exhausted(&self) -> bool { self == &DecodeError::ExhaustedInput }
+    fn bad_opcode(&self) -> bool { self == &DecodeError::InvalidOpcode }
+    fn bad_operand(&self) -> bool { self == &DecodeError::InvalidOperand }
+}
+
+#[allow(non_camel_case_types)]
+#[derive(Debug, Copy, Clone, PartialEq)]
+enum OperandSpec {
+    Nothing,
+    // the register in modrm_rrr
+    RegRRR,
+    // the register in modrm_mmm (eg modrm mod bits were 11)
+    RegMMM,
+    // the register selected by vex-vvvv bits
+    RegVex,
+    // the register `al`. Used for MOVS.
+    AL,
+    // the register `cl`. Used for SHLD and SHRD.
+    CL,
+    ImmI8,
+    ImmI16,
+    ImmI32,
+    ImmU8,
+    ImmU16,
+    ImmU32,
+    DispU16,
+    DispU32,
+    Deref,
+    Deref_esi,
+    Deref_edi,
+    RegDisp,
+    RegScale,
+    RegIndexBase,
+    RegIndexBaseDisp,
+    RegScaleDisp,
+    RegIndexBaseScale,
+    RegIndexBaseScaleDisp
+}
+
+// the Hash, Eq, and PartialEq impls here are possibly misleading.
+// They exist because downstream some structs are spelled like
+// Foo<T> for T == x86_64. This is only to access associated types
+// which themselves are bounded, but their #[derive] require T to
+// implement these traits.
+#[cfg(feature="use-serde")]
+#[derive(Hash, Eq, PartialEq, Debug, Serialize, Deserialize)]
+#[allow(non_camel_case_types)]
+pub struct Arch;
+
+#[cfg(not(feature="use-serde"))]
+#[derive(Hash, Eq, PartialEq, Debug)]
+#[allow(non_camel_case_types)]
+pub struct Arch;
+
+impl yaxpeax_arch::Arch for Arch {
+    type Address = u32;
+    type Instruction = Instruction;
+    type DecodeError = DecodeError;
+    type Decoder = InstDecoder;
+    type Operand = Operand;
+}
+
+impl LengthedInstruction for Instruction {
+    type Unit = u32;
+    fn len(&self) -> u32 {
+        self.length.into()
+    }
+    fn min_size() -> u32 {
+        1
+    }
+}
+
+#[derive(PartialEq)]
+pub struct InstDecoder {
+    // extensions tracked here:
+    //  0. SSE3
+    //  1. SSSE3
+    //  2. monitor (intel-only?)
+    //  3. vmx (some atom chips still lack it)
+    //  4. fma3 (intel haswell/broadwell+, amd piledriver+)
+    //  5. cmpxchg16b (some amd are missingt this one)
+    //  6. sse4.1
+    //  7. sse4.2
+    //  8. movbe
+    //  9. popcnt (independent of BMI)
+    // 10. aesni
+    // 11. xsave (xsave, xrestor, xsetbv, xgetbv)
+    // 12. rdrand (intel ivybridge+, amd ..??)
+    // 13. sgx (eadd, eblock, ecreate, edbgrd, edbgwr, einit, eldb, eldu, epa, eremove, etrace,
+    //     ewb, eenter, eexit, egetkey, ereport, eresume)
+    // 14. bmi1 (intel haswell+, amd jaguar+)
+    // 15. avx2 (intel haswell+, amd excavator+)
+    // 16. bmi2 (intel ?, amd ?)
+    // 17. invpcid
+    // 18. mpx
+    // 19. avx512_f
+    // 20. avx512_dq
+    // 21. rdseed
+    // 22. adx
+    // 23. avx512_fma
+    // 24. pcommit
+    // 25. clflushopt
+    // 26. clwb
+    // 27. avx512_pf
+    // 28. avx512_er
+    // 29. avx512_cd
+    // 30. sha
+    // 31. avx512_bw
+    // 32. avx512_vl
+    // 33. prefetchwt1
+    // 34. avx512_vbmi
+    // 35. avx512_vbmi2
+    // 36. gfni (galois field instructions)
+    // 37. vaes
+    // 38. pclmulqdq
+    // 39. avx_vnni
+    // 40. avx512_bitalg
+    // 41. avx512_vpopcntdq
+    // 42. avx512_4vnniw
+    // 43. avx512_4fmaps
+    // 44. cx8 // cmpxchg8 - is this actually optional in x86_64?
+    // 45. syscall // syscall/sysret - actually optional in x86_64?
+    // 46. rdtscp // actually optional in x86_64?
+    // 47. abm (lzcnt, popcnt)
+    // 48. sse4a
+    // 49. 3dnowprefetch // actually optional?
+    // 50. xop
+    // 51. skinit
+    // 52. tbm
+    // 53. intel quirks
+    // 54. amd quirks
+    // 55. avx (intel ?, amd ?)
+    flags: u64,
+}
+
+impl InstDecoder {
+    /// Instantiates an x86_64 decoder that decodes the bare minimum of x86_64.
+    ///
+    /// Pedantic and only decodes what the spec says is well-defined, rejecting undefined sequences
+    /// and any instructions defined by extensions.
+    pub fn minimal() -> Self {
+        InstDecoder {
+            flags: 0,
+        }
+    }
+
+    pub fn sse3(&self) -> bool {
+        self.flags & (1 << 0) != 0
+    }
+
+    pub fn with_sse3(mut self) -> Self {
+        self.flags |= 1 << 0;
+        self
+    }
+
+    pub fn ssse3(&self) -> bool {
+        self.flags & (1 << 1) != 0
+    }
+
+    pub fn with_ssse3(mut self) -> Self {
+        self.flags |= 1 << 1;
+        self
+    }
+
+    pub fn monitor(&self) -> bool {
+        self.flags & (1 << 2) != 0
+    }
+
+    pub fn with_monitor(mut self) -> Self {
+        self.flags |= 1 << 2;
+        self
+    }
+
+    pub fn vmx(&self) -> bool {
+        self.flags & (1 << 3) != 0
+    }
+
+    pub fn with_vmx(mut self) -> Self {
+        self.flags |= 1 << 3;
+        self
+    }
+
+    pub fn fma3(&self) -> bool {
+        self.flags & (1 << 4) != 0
+    }
+
+    pub fn with_fma3(mut self) -> Self {
+        self.flags |= 1 << 4;
+        self
+    }
+
+    pub fn cmpxchg16b(&self) -> bool {
+        self.flags & (1 << 5) != 0
+    }
+
+    pub fn with_cmpxchg16b(mut self) -> Self {
+        self.flags |= 1 << 5;
+        self
+    }
+
+    pub fn sse4_1(&self) -> bool {
+        self.flags & (1 << 6) != 0
+    }
+
+    pub fn with_sse4_1(mut self) -> Self {
+        self.flags |= 1 << 6;
+        self
+    }
+
+    pub fn sse4_2(&self) -> bool {
+        self.flags & (1 << 7) != 0
+    }
+
+    pub fn with_sse4_2(mut self) -> Self {
+        self.flags |= 1 << 7;
+        self
+    }
+
+    pub fn movbe(&self) -> bool {
+        self.flags & (1 << 8) != 0
+    }
+
+    pub fn with_movbe(mut self) -> Self {
+        self.flags |= 1 << 8;
+        self
+    }
+
+    pub fn popcnt(&self) -> bool {
+        self.flags & (1 << 9) != 0
+    }
+
+    pub fn with_popcnt(mut self) -> Self {
+        self.flags |= 1 << 9;
+        self
+    }
+
+    pub fn aesni(&self) -> bool {
+        self.flags & (1 << 10) != 0
+    }
+
+    pub fn with_aesni(mut self) -> Self {
+        self.flags |= 1 << 10;
+        self
+    }
+
+    pub fn xsave(&self) -> bool {
+        self.flags & (1 << 11) != 0
+    }
+
+    pub fn with_xsave(mut self) -> Self {
+        self.flags |= 1 << 11;
+        self
+    }
+
+    pub fn rdrand(&self) -> bool {
+        self.flags & (1 << 12) != 0
+    }
+
+    pub fn with_rdrand(mut self) -> Self {
+        self.flags |= 1 << 12;
+        self
+    }
+
+    pub fn sgx(&self) -> bool {
+        self.flags & (1 << 13) != 0
+    }
+
+    pub fn with_sgx(mut self) -> Self {
+        self.flags |= 1 << 13;
+        self
+    }
+
+    pub fn bmi1(&self) -> bool {
+        self.flags & (1 << 14) != 0
+    }
+
+    pub fn with_bmi1(mut self) -> Self {
+        self.flags |= 1 << 14;
+        self
+    }
+
+    pub fn avx2(&self) -> bool {
+        self.flags & (1 << 15) != 0
+    }
+
+    pub fn with_avx2(mut self) -> Self {
+        self.flags |= 1 << 15;
+        self
+    }
+
+    pub fn bmi2(&self) -> bool {
+        self.flags & (1 << 16) != 0
+    }
+
+    pub fn with_bmi2(mut self) -> Self {
+        self.flags |= 1 << 16;
+        self
+    }
+
+    pub fn invpcid(&self) -> bool {
+        self.flags & (1 << 17) != 0
+    }
+
+    pub fn with_invpcid(mut self) -> Self {
+        self.flags |= 1 << 17;
+        self
+    }
+
+    pub fn mpx(&self) -> bool {
+        self.flags & (1 << 18) != 0
+    }
+
+    pub fn with_mpx(mut self) -> Self {
+        self.flags |= 1 << 18;
+        self
+    }
+
+    pub fn avx512_f(&self) -> bool {
+        self.flags & (1 << 19) != 0
+    }
+
+    pub fn with_avx512_f(mut self) -> Self {
+        self.flags |= 1 << 19;
+        self
+    }
+
+    pub fn avx512_dq(&self) -> bool {
+        self.flags & (1 << 20) != 0
+    }
+
+    pub fn with_avx512_dq(mut self) -> Self {
+        self.flags |= 1 << 20;
+        self
+    }
+
+    pub fn rdseed(&self) -> bool {
+        self.flags & (1 << 21) != 0
+    }
+
+    pub fn with_rdseed(mut self) -> Self {
+        self.flags |= 1 << 21;
+        self
+    }
+
+    pub fn adx(&self) -> bool {
+        self.flags & (1 << 22) != 0
+    }
+
+    pub fn with_adx(mut self) -> Self {
+        self.flags |= 1 << 22;
+        self
+    }
+
+    pub fn avx512_fma(&self) -> bool {
+        self.flags & (1 << 23) != 0
+    }
+
+    pub fn with_avx512_fma(mut self) -> Self {
+        self.flags |= 1 << 23;
+        self
+    }
+
+    pub fn pcommit(&self) -> bool {
+        self.flags & (1 << 24) != 0
+    }
+
+    pub fn with_pcommit(mut self) -> Self {
+        self.flags |= 1 << 24;
+        self
+    }
+
+    pub fn clflushopt(&self) -> bool {
+        self.flags & (1 << 25) != 0
+    }
+
+    pub fn with_clflushopt(mut self) -> Self {
+        self.flags |= 1 << 25;
+        self
+    }
+
+    pub fn clwb(&self) -> bool {
+        self.flags & (1 << 26) != 0
+    }
+
+    pub fn with_clwb(mut self) -> Self {
+        self.flags |= 1 << 26;
+        self
+    }
+
+    pub fn avx512_pf(&self) -> bool {
+        self.flags & (1 << 27) != 0
+    }
+
+    pub fn with_avx512_pf(mut self) -> Self {
+        self.flags |= 1 << 27;
+        self
+    }
+
+    pub fn avx512_er(&self) -> bool {
+        self.flags & (1 << 28) != 0
+    }
+
+    pub fn with_avx512_er(mut self) -> Self {
+        self.flags |= 1 << 28;
+        self
+    }
+
+    pub fn avx512_cd(&self) -> bool {
+        self.flags & (1 << 29) != 0
+    }
+
+    pub fn with_avx512_cd(mut self) -> Self {
+        self.flags |= 1 << 29;
+        self
+    }
+
+    pub fn sha(&self) -> bool {
+        self.flags & (1 << 30) != 0
+    }
+
+    pub fn with_sha(mut self) -> Self {
+        self.flags |= 1 << 30;
+        self
+    }
+
+    pub fn avx512_bw(&self) -> bool {
+        self.flags & (1 << 31) != 0
+    }
+
+    pub fn with_avx512_bw(mut self) -> Self {
+        self.flags |= 1 << 31;
+        self
+    }
+
+    pub fn avx512_vl(&self) -> bool {
+        self.flags & (1 << 32) != 0
+    }
+
+    pub fn with_avx512_vl(mut self) -> Self {
+        self.flags |= 1 << 32;
+        self
+    }
+
+    pub fn prefetchwt1(&self) -> bool {
+        self.flags & (1 << 33) != 0
+    }
+
+    pub fn with_prefetchwt1(mut self) -> Self {
+        self.flags |= 1 << 33;
+        self
+    }
+
+    pub fn avx512_vbmi(&self) -> bool {
+        self.flags & (1 << 34) != 0
+    }
+
+    pub fn with_avx512_vbmi(mut self) -> Self {
+        self.flags |= 1 << 34;
+        self
+    }
+
+    pub fn avx512_vbmi2(&self) -> bool {
+        self.flags & (1 << 35) != 0
+    }
+
+    pub fn with_avx512_vbmi2(mut self) -> Self {
+        self.flags |= 1 << 35;
+        self
+    }
+
+    pub fn gfni(&self) -> bool {
+        self.flags & (1 << 36) != 0
+    }
+
+    pub fn with_gfni(mut self) -> Self {
+        self.flags |= 1 << 36;
+        self
+    }
+
+    pub fn vaes(&self) -> bool {
+        self.flags & (1 << 37) != 0
+    }
+
+    pub fn with_vaes(mut self) -> Self {
+        self.flags |= 1 << 37;
+        self
+    }
+
+    pub fn pclmulqdq(&self) -> bool {
+        self.flags & (1 << 38) != 0
+    }
+
+    pub fn with_pclmulqdq(mut self) -> Self {
+        self.flags |= 1 << 38;
+        self
+    }
+
+    pub fn avx_vnni(&self) -> bool {
+        self.flags & (1 << 39) != 0
+    }
+
+    pub fn with_avx_vnni(mut self) -> Self {
+        self.flags |= 1 << 39;
+        self
+    }
+
+    pub fn avx512_bitalg(&self) -> bool {
+        self.flags & (1 << 40) != 0
+    }
+
+    pub fn with_avx512_bitalg(mut self) -> Self {
+        self.flags |= 1 << 40;
+        self
+    }
+
+    pub fn avx512_vpopcntdq(&self) -> bool {
+        self.flags & (1 << 41) != 0
+    }
+
+    pub fn with_avx512_vpopcntdq(mut self) -> Self {
+        self.flags |= 1 << 41;
+        self
+    }
+
+    pub fn avx512_4vnniw(&self) -> bool {
+        self.flags & (1 << 42) != 0
+    }
+
+    pub fn with_avx512_4vnniw(mut self) -> Self {
+        self.flags |= 1 << 42;
+        self
+    }
+
+    pub fn avx512_4fmaps(&self) -> bool {
+        self.flags & (1 << 43) != 0
+    }
+
+    pub fn with_avx512_4fmaps(mut self) -> Self {
+        self.flags |= 1 << 43;
+        self
+    }
+
+    pub fn cx8(&self) -> bool {
+        self.flags & (1 << 44) != 0
+    }
+
+    pub fn with_cx8(mut self) -> Self {
+        self.flags |= 1 << 44;
+        self
+    }
+
+    pub fn syscall(&self) -> bool {
+        self.flags & (1 << 45) != 0
+    }
+
+    pub fn with_syscall(mut self) -> Self {
+        self.flags |= 1 << 45;
+        self
+    }
+
+    pub fn rdtscp(&self) -> bool {
+        self.flags & (1 << 46) != 0
+    }
+
+    pub fn with_rdtscp(mut self) -> Self {
+        self.flags |= 1 << 46;
+        self
+    }
+
+    pub fn abm(&self) -> bool {
+        self.flags & (1 << 47) != 0
+    }
+
+    pub fn with_abm(mut self) -> Self {
+        self.flags |= 1 << 47;
+        self
+    }
+
+    pub fn sse4a(&self) -> bool {
+        self.flags & (1 << 48) != 0
+    }
+
+    pub fn with_sse4a(mut self) -> Self {
+        self.flags |= 1 << 48;
+        self
+    }
+
+    pub fn _3dnowprefetch(&self) -> bool {
+        self.flags & (1 << 49) != 0
+    }
+
+    pub fn with_3dnowprefetch(mut self) -> Self {
+        self.flags |= 1 << 49;
+        self
+    }
+
+    pub fn xop(&self) -> bool {
+        self.flags & (1 << 50) != 0
+    }
+
+    pub fn with_xop(mut self) -> Self {
+        self.flags |= 1 << 50;
+        self
+    }
+
+    pub fn skinit(&self) -> bool {
+        self.flags & (1 << 51) != 0
+    }
+
+    pub fn with_skinit(mut self) -> Self {
+        self.flags |= 1 << 51;
+        self
+    }
+
+    pub fn tbm(&self) -> bool {
+        self.flags & (1 << 52) != 0
+    }
+
+    pub fn with_tbm(mut self) -> Self {
+        self.flags |= 1 << 52;
+        self
+    }
+
+    pub fn intel_quirks(&self) -> bool {
+        self.flags & (1 << 53) != 0
+    }
+
+    pub fn with_intel_quirks(mut self) -> Self {
+        self.flags |= 1 << 53;
+        self
+    }
+
+    pub fn amd_quirks(&self) -> bool {
+        self.flags & (1 << 54) != 0
+    }
+
+    pub fn with_amd_quirks(mut self) -> Self {
+        self.flags |= 1 << 54;
+        self
+    }
+
+    pub fn avx(&self) -> bool {
+        self.flags & (1 << 55) != 0
+    }
+
+    pub fn with_avx(mut self) -> Self {
+        self.flags |= 1 << 55;
+        self
+    }
+
+    /// Optionally reject or reinterpret instruction according to the decoder's
+    /// declared extensions.
+    fn revise_instruction(&self, inst: &mut Instruction) -> Result<(), DecodeError> {
+        match inst.opcode {
+            Opcode::TZCNT => {
+                if !self.bmi1() {
+                    // tzcnt is only supported if bmi1 is enabled. without bmi1, this decodes as
+                    // bsf.
+                    inst.opcode = Opcode::BSF;
+                }
+            }
+            Opcode::LDDQU |
+            Opcode::ADDSUBPS |
+            Opcode::ADDSUBPD |
+            Opcode::HADDPS |
+            Opcode::HSUBPS |
+            Opcode::HADDPD |
+            Opcode::HSUBPD |
+            Opcode::MOVSHDUP |
+            Opcode::MOVSLDUP |
+            Opcode::MOVDDUP |
+            Opcode::MONITOR |
+            Opcode::MWAIT => {
+                // via Intel section 5.7, SSE3 Instructions
+                if !self.sse3() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::PHADDW |
+            Opcode::PHADDSW |
+            Opcode::PHADDD |
+            Opcode::PHSUBW |
+            Opcode::PHSUBSW |
+            Opcode::PHSUBD |
+            Opcode::PABSB |
+            Opcode::PABSW |
+            Opcode::PABSD |
+            Opcode::PMADDUBSW |
+            Opcode::PMULHRSU |
+            Opcode::PSHUFB |
+            Opcode::PSIGNB |
+            Opcode::PSIGNW |
+            Opcode::PSIGND |
+            Opcode::PALIGNR => {
+                // via Intel section 5.8, SSSE3 Instructions
+                if !self.ssse3() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::PMULLD |
+            Opcode::PMULDQ |
+            Opcode::MOVNTDQA |
+            Opcode::BLENDPD |
+            Opcode::BLENDPS |
+            Opcode::BLENDVPD |
+            Opcode::BLENDVPS |
+            Opcode::BLENDDVB |
+            Opcode::BLENDW |
+            Opcode::PMINUW |
+            Opcode::PMINUD |
+            Opcode::PMINSB |
+            Opcode::PMINSD |
+            Opcode::PMAXUW |
+            Opcode::PMAXUD |
+            Opcode::PMAXSB |
+            Opcode::ROUNDPS |
+            Opcode::ROUNDPD |
+            Opcode::ROUNDSS |
+            Opcode::ROUNDSD |
+            Opcode::EXTRACTPS |
+            Opcode::INSERTPS |
+            Opcode::PINSRB |
+            Opcode::PINSRD |
+            Opcode::PINSRQ |
+            Opcode::PEXTRB |
+            Opcode::PEXTRW |
+            Opcode::PEXTRQ |
+            Opcode::PMOVSXBW |
+            Opcode::PMOVZXBW |
+            Opcode::PMOVSXBD |
+            Opcode::PMOVZXBD |
+            Opcode::PMOVSXWD |
+            Opcode::PMOVZXWD |
+            Opcode::PMOVSXBQ |
+            Opcode::PMOVZXBQ |
+            Opcode::PMOVSXWQ |
+            Opcode::PMOVZXWQ |
+            Opcode::PMOVSXDQ |
+            Opcode::PMOVZXDQ |
+            Opcode::MPSADBW |
+            Opcode::PHMINPOSUW |
+            Opcode::PTEST |
+            Opcode::PCMPEQQ |
+            Opcode::PACKUSDW => {
+                // via Intel section 5.10, SSE4.1 Instructions
+                if !self.sse4_1() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::PCMPESTRI |
+            Opcode::PCMPESTRM |
+            Opcode::PCMPISTRI |
+            Opcode::PCMPISTRM |
+            Opcode::PCMPGTQ => {
+                // via Intel section 5.11, SSE4.2 Instructions
+                if !self.sse4_2() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::AESDEC |
+            Opcode::AESDECLAST |
+            Opcode::AESENC |
+            Opcode::AESENCLAST |
+            Opcode::AESIMC |
+            Opcode::AESKEYGENASSIST => {
+                // via Intel section 5.12. AESNI AND PCLMULQDQ
+                if !self.aesni() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::PCLMULQDQ => {
+                // via Intel section 5.12. AESNI AND PCLMULQDQ
+                if !self.pclmulqdq() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            // AVX...
+            /* // TODO
+            Opcode::XABORT |
+            Opcode::XACQUIRE |
+            Opcode::XRELEASE |
+            Opcode::XBEGIN |
+            Opcode::XEND |
+            Opcode::XTEST => {
+                if !self.tsx() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(());
+                }
+            }
+            */
+            /* // TODO
+            Opcode::SHA1MSG1 |
+            Opcode::SHA1MSG2 |
+            Opcode::SHA1NEXTE |
+            Opcode::SHA1RNDS4 |
+            Opcode::SHA256MSG1 |
+            Opcode::SHA256MSG2 |
+            Opcode::SHA256RNDS2 => {
+                if !self.sha() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(());
+                }
+            }*/
+            Opcode::ENCLV |
+            Opcode::ENCLS |
+            Opcode::ENCLU => {
+                if !self.sgx() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::VMOVDDUP |
+            Opcode::VPSHUFLW |
+            Opcode::VHADDPS |
+            Opcode::VHSUBPS |
+            Opcode::VADDSUBPS |
+            Opcode::VCVTPD2DQ |
+            Opcode::VLDDQU |
+            Opcode::VCOMISD |
+            Opcode::VCOMISS |
+            Opcode::VUCOMISD |
+            Opcode::VUCOMISS |
+            Opcode::VADDPD |
+            Opcode::VADDPS |
+            Opcode::VADDSD |
+            Opcode::VADDSS |
+            Opcode::VADDSUBPD |
+            Opcode::VBLENDPD |
+            Opcode::VBLENDPS |
+            Opcode::VBLENDVPD |
+            Opcode::VBLENDVPS |
+            Opcode::VBROADCASTF128 |
+            Opcode::VBROADCASTI128 |
+            Opcode::VBROADCASTSD |
+            Opcode::VBROADCASTSS |
+            Opcode::VCMPSD |
+            Opcode::VCMPSS |
+            Opcode::VCMPPD |
+            Opcode::VCMPPS |
+            Opcode::VCVTDQ2PD |
+            Opcode::VCVTDQ2PS |
+            Opcode::VCVTPD2PS |
+            Opcode::VCVTPH2PS |
+            Opcode::VCVTPS2DQ |
+            Opcode::VCVTPS2PD |
+            Opcode::VCVTSS2SD |
+            Opcode::VCVTSI2SS |
+            Opcode::VCVTSI2SD |
+            Opcode::VCVTSD2SI |
+            Opcode::VCVTSD2SS |
+            Opcode::VCVTPS2PH |
+            Opcode::VCVTSS2SI |
+            Opcode::VCVTTPD2DQ |
+            Opcode::VCVTTPS2DQ |
+            Opcode::VCVTTSS2SI |
+            Opcode::VCVTTSD2SI |
+            Opcode::VDIVPD |
+            Opcode::VDIVPS |
+            Opcode::VDIVSD |
+            Opcode::VDIVSS |
+            Opcode::VDPPD |
+            Opcode::VDPPS |
+            Opcode::VEXTRACTF128 |
+            Opcode::VEXTRACTI128 |
+            Opcode::VEXTRACTPS |
+            Opcode::VFMADD132PD |
+            Opcode::VFMADD132PS |
+            Opcode::VFMADD132SD |
+            Opcode::VFMADD132SS |
+            Opcode::VFMADD213PD |
+            Opcode::VFMADD213PS |
+            Opcode::VFMADD213SD |
+            Opcode::VFMADD213SS |
+            Opcode::VFMADD231PD |
+            Opcode::VFMADD231PS |
+            Opcode::VFMADD231SD |
+            Opcode::VFMADD231SS |
+            Opcode::VFMADDSUB132PD |
+            Opcode::VFMADDSUB132PS |
+            Opcode::VFMADDSUB213PD |
+            Opcode::VFMADDSUB213PS |
+            Opcode::VFMADDSUB231PD |
+            Opcode::VFMADDSUB231PS |
+            Opcode::VFMSUB132PD |
+            Opcode::VFMSUB132PS |
+            Opcode::VFMSUB132SD |
+            Opcode::VFMSUB132SS |
+            Opcode::VFMSUB213PD |
+            Opcode::VFMSUB213PS |
+            Opcode::VFMSUB213SD |
+            Opcode::VFMSUB213SS |
+            Opcode::VFMSUB231PD |
+            Opcode::VFMSUB231PS |
+            Opcode::VFMSUB231SD |
+            Opcode::VFMSUB231SS |
+            Opcode::VFMSUBADD132PD |
+            Opcode::VFMSUBADD132PS |
+            Opcode::VFMSUBADD213PD |
+            Opcode::VFMSUBADD213PS |
+            Opcode::VFMSUBADD231PD |
+            Opcode::VFMSUBADD231PS |
+            Opcode::VFNMADD132PD |
+            Opcode::VFNMADD132PS |
+            Opcode::VFNMADD132SD |
+            Opcode::VFNMADD132SS |
+            Opcode::VFNMADD213PD |
+            Opcode::VFNMADD213PS |
+            Opcode::VFNMADD213SD |
+            Opcode::VFNMADD213SS |
+            Opcode::VFNMADD231PD |
+            Opcode::VFNMADD231PS |
+            Opcode::VFNMADD231SD |
+            Opcode::VFNMADD231SS |
+            Opcode::VFNMSUB132PD |
+            Opcode::VFNMSUB132PS |
+            Opcode::VFNMSUB132SD |
+            Opcode::VFNMSUB132SS |
+            Opcode::VFNMSUB213PD |
+            Opcode::VFNMSUB213PS |
+            Opcode::VFNMSUB213SD |
+            Opcode::VFNMSUB213SS |
+            Opcode::VFNMSUB231PD |
+            Opcode::VFNMSUB231PS |
+            Opcode::VFNMSUB231SD |
+            Opcode::VFNMSUB231SS |
+            Opcode::VGATHERDPD |
+            Opcode::VGATHERDPS |
+            Opcode::VGATHERQPD |
+            Opcode::VGATHERQPS |
+            Opcode::VHADDPD |
+            Opcode::VHSUBPD |
+            Opcode::VINSERTF128 |
+            Opcode::VINSERTI128 |
+            Opcode::VINSERTPS |
+            Opcode::VMASKMOVDQU |
+            Opcode::VMASKMOVPD |
+            Opcode::VMASKMOVPS |
+            Opcode::VMAXPD |
+            Opcode::VMAXPS |
+            Opcode::VMAXSD |
+            Opcode::VMAXSS |
+            Opcode::VMINPD |
+            Opcode::VMINPS |
+            Opcode::VMINSD |
+            Opcode::VMINSS |
+            Opcode::VMOVAPD |
+            Opcode::VMOVAPS |
+            Opcode::VMOVD |
+            Opcode::VMOVDQA |
+            Opcode::VMOVDQU |
+            Opcode::VMOVHLPS |
+            Opcode::VMOVHPD |
+            Opcode::VMOVHPS |
+            Opcode::VMOVLHPS |
+            Opcode::VMOVLPD |
+            Opcode::VMOVLPS |
+            Opcode::VMOVMSKPD |
+            Opcode::VMOVMSKPS |
+            Opcode::VMOVNTDQ |
+            Opcode::VMOVNTDQA |
+            Opcode::VMOVNTPD |
+            Opcode::VMOVNTPS |
+            Opcode::VMOVQ |
+            Opcode::VMOVSS |
+            Opcode::VMOVSD |
+            Opcode::VMOVSHDUP |
+            Opcode::VMOVSLDUP |
+            Opcode::VMOVUPD |
+            Opcode::VMOVUPS |
+            Opcode::VMPSADBW |
+            Opcode::VMULPD |
+            Opcode::VMULPS |
+            Opcode::VMULSD |
+            Opcode::VMULSS |
+            Opcode::VPABSB |
+            Opcode::VPABSD |
+            Opcode::VPABSW |
+            Opcode::VPACKSSDW |
+            Opcode::VPACKSSWB |
+            Opcode::VPACKUSWB |
+            Opcode::VPADDB |
+            Opcode::VPADDD |
+            Opcode::VPADDQ |
+            Opcode::VPADDSB |
+            Opcode::VPADDSW |
+            Opcode::VPADDUSB |
+            Opcode::VPADDUSW |
+            Opcode::VPADDW |
+            Opcode::VPALIGNR |
+            Opcode::VPAND |
+            Opcode::VPANDN |
+            Opcode::VPAVGB |
+            Opcode::VPAVGW |
+            Opcode::VPBLENDD |
+            Opcode::VPBLENDVB |
+            Opcode::VPBLENDW |
+            Opcode::VPBROADCASTB |
+            Opcode::VPBROADCASTD |
+            Opcode::VPBROADCASTQ |
+            Opcode::VPBROADCASTW |
+            Opcode::VPCLMULQDQ |
+            Opcode::VPCMPEQB |
+            Opcode::VPCMPEQD |
+            Opcode::VPCMPEQQ |
+            Opcode::VPCMPEQW |
+            Opcode::VPCMPGTB |
+            Opcode::VPCMPGTD |
+            Opcode::VPCMPGTQ |
+            Opcode::VPCMPGTW |
+            Opcode::VPCMPISTRI |
+            Opcode::VPCMPISTRM |
+            Opcode::VPERM2F128 |
+            Opcode::VPERM2I128 |
+            Opcode::VPERMD |
+            Opcode::VPERMILPD |
+            Opcode::VPERMILPS |
+            Opcode::VPERMPD |
+            Opcode::VPERMPS |
+            Opcode::VPERMQ |
+            Opcode::VPEXTRB |
+            Opcode::VPEXTRD |
+            Opcode::VPEXTRQ |
+            Opcode::VPEXTRW |
+            Opcode::VPGATHERDD |
+            Opcode::VPGATHERDQ |
+            Opcode::VPGATHERQD |
+            Opcode::VPGATHERQQ |
+            Opcode::VPHADDD |
+            Opcode::VPHADDSW |
+            Opcode::VPHADDW |
+            Opcode::VPHADDUBSW |
+            Opcode::VPHMINPOSUW |
+            Opcode::VPHSUBD |
+            Opcode::VPHSUBSW |
+            Opcode::VPHSUBW |
+            Opcode::VPINSRB |
+            Opcode::VPINSRD |
+            Opcode::VPINSRQ |
+            Opcode::VPINSRW |
+            Opcode::VPMADDWD |
+            Opcode::VPMASKMOVD |
+            Opcode::VPMASKMOVQ |
+            Opcode::VPMAXSB |
+            Opcode::VPMAXSD |
+            Opcode::VPMAXSW |
+            Opcode::VPMAXUD |
+            Opcode::VPMINSD |
+            Opcode::VPMINUD |
+            Opcode::VPMOVMSKB |
+            Opcode::VPMOVSXBD |
+            Opcode::VPMOVSXBQ |
+            Opcode::VPMOVSXBW |
+            Opcode::VPMOVSXDQ |
+            Opcode::VPMOVSXWD |
+            Opcode::VPMOVSXWQ |
+            Opcode::VPMOVZXBD |
+            Opcode::VPMOVZXBQ |
+            Opcode::VPMOVZXBW |
+            Opcode::VPMOVZXDQ |
+            Opcode::VPMOVZXWD |
+            Opcode::VPMOVZXWQ |
+            Opcode::VPMULDQ |
+            Opcode::VPMULHRSW |
+            Opcode::VPMULHUW |
+            Opcode::VPMULHW |
+            Opcode::VPMULLD |
+            Opcode::VPMULLW |
+            Opcode::VPMULUDQ |
+            Opcode::VPOR |
+            Opcode::VPSADBW |
+            Opcode::VPSHUFB |
+            Opcode::VPSHUFD |
+            Opcode::VPSIGNB |
+            Opcode::VPSIGND |
+            Opcode::VPSIGNW |
+            Opcode::VPSLLD |
+            Opcode::VPSLLDQ |
+            Opcode::VPSLLQ |
+            Opcode::VPSLLVD |
+            Opcode::VPSLLVQ |
+            Opcode::VPSLLW |
+            Opcode::VPSRAD |
+            Opcode::VPSRAVD |
+            Opcode::VPSRAW |
+            Opcode::VPSRLD |
+            Opcode::VPSRLDQ |
+            Opcode::VPSRLQ |
+            Opcode::VPSRLVD |
+            Opcode::VPSRLVQ |
+            Opcode::VPSRLW |
+            Opcode::VPSUBB |
+            Opcode::VPSUBD |
+            Opcode::VPSUBQ |
+            Opcode::VPSUBSB |
+            Opcode::VPSUBSW |
+            Opcode::VPSUBUSB |
+            Opcode::VPSUBUSW |
+            Opcode::VPSUBW |
+            Opcode::VPTEST |
+            Opcode::VPUNPCKHBW |
+            Opcode::VPUNPCKHDQ |
+            Opcode::VPUNPCKHQDQ |
+            Opcode::VPUNPCKHWD |
+            Opcode::VPUNPCKLBW |
+            Opcode::VPUNPCKLDQ |
+            Opcode::VPUNPCKLQDQ |
+            Opcode::VPUNPCKLWD |
+            Opcode::VPXOR |
+            Opcode::VRCPPS |
+            Opcode::VROUNDPD |
+            Opcode::VROUNDPS |
+            Opcode::VROUNDSD |
+            Opcode::VROUNDSS |
+            Opcode::VRSQRTPS |
+            Opcode::VRSQRTSS |
+            Opcode::VRCPSS |
+            Opcode::VSHUFPD |
+            Opcode::VSHUFPS |
+            Opcode::VSQRTPD |
+            Opcode::VSQRTPS |
+            Opcode::VSQRTSS |
+            Opcode::VSQRTSD |
+            Opcode::VSUBPD |
+            Opcode::VSUBPS |
+            Opcode::VSUBSD |
+            Opcode::VSUBSS |
+            Opcode::VTESTPD |
+            Opcode::VTESTPS |
+            Opcode::VUNPCKHPD |
+            Opcode::VUNPCKHPS |
+            Opcode::VUNPCKLPD |
+            Opcode::VUNPCKLPS |
+            Opcode::VXORPD |
+            Opcode::VXORPS |
+            Opcode::VZEROUPPER => {
+                // TODO: check a table for these
+                if !self.avx() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            Opcode::VAESDEC |
+            Opcode::VAESDECLAST |
+            Opcode::VAESENC |
+            Opcode::VAESENCLAST |
+            Opcode::VAESIMC |
+            Opcode::VAESKEYGENASSIST => {
+                // TODO: check a table for these
+                if !self.avx() || !self.aesni() {
+                    inst.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+            other => {
+                if !self.bmi1() {
+                    if BMI1.contains(&other) {
+                        return Err(DecodeError::InvalidOpcode);
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+}
+
+impl Default for InstDecoder {
+    /// Instantiates an x86_64 decoder that probably decodes what you want.
+    ///
+    /// Attempts to match real processors in interpretation of undefined sequences, and decodes any
+    /// instruction defined in any extension.
+    fn default() -> Self {
+        Self {
+            flags: 0xffffffff_ffffffff,
+        }
+    }
+}
+
+impl Decoder<Instruction> for InstDecoder {
+    type Error = DecodeError;
+
+    fn decode<T: IntoIterator<Item=u8>>(&self, bytes: T) -> Result<Instruction, Self::Error> {
+        let mut instr = Instruction::invalid();
+        decode_one(self, bytes, &mut instr)
+            .map(|_: ()| instr)
+    }
+    fn decode_into<T: IntoIterator<Item=u8>>(&self, instr: &mut Instruction, bytes: T) -> Result<(), Self::Error> {
+        decode_one(self, bytes, instr)
+    }
+}
+
+impl Opcode {
+    pub fn condition(&self) -> Option<ConditionCode> {
+        match self {
+            Opcode::JO |
+            Opcode::CMOVO |
+            Opcode::SETO => { Some(ConditionCode::O) },
+            Opcode::JNO |
+            Opcode::CMOVNO |
+            Opcode::SETNO => { Some(ConditionCode::NO) },
+            Opcode::JB |
+            Opcode::CMOVB |
+            Opcode::SETB => { Some(ConditionCode::B) },
+            Opcode::JNB |
+            Opcode::CMOVNB |
+            Opcode::SETAE => { Some(ConditionCode::AE) },
+            Opcode::JZ |
+            Opcode::CMOVZ |
+            Opcode::SETZ => { Some(ConditionCode::Z) },
+            Opcode::JNZ |
+            Opcode::CMOVNZ |
+            Opcode::SETNZ => { Some(ConditionCode::NZ) },
+            Opcode::JA |
+            Opcode::CMOVA |
+            Opcode::SETA => { Some(ConditionCode::A) },
+            Opcode::JNA |
+            Opcode::CMOVNA |
+            Opcode::SETBE => { Some(ConditionCode::BE) },
+            Opcode::JS |
+            Opcode::CMOVS |
+            Opcode::SETS => { Some(ConditionCode::S) },
+            Opcode::JNS |
+            Opcode::CMOVNS |
+            Opcode::SETNS => { Some(ConditionCode::NS) },
+            Opcode::JP |
+            Opcode::CMOVP |
+            Opcode::SETP => { Some(ConditionCode::P) },
+            Opcode::JNP |
+            Opcode::CMOVNP |
+            Opcode::SETNP => { Some(ConditionCode::NP) },
+            Opcode::JL |
+            Opcode::CMOVL |
+            Opcode::SETL => { Some(ConditionCode::L) },
+            Opcode::JGE |
+            Opcode::CMOVGE |
+            Opcode::SETGE => { Some(ConditionCode::GE) },
+            Opcode::JG |
+            Opcode::CMOVG |
+            Opcode::SETG => { Some(ConditionCode::G) },
+            Opcode::JLE |
+            Opcode::CMOVLE |
+            Opcode::SETLE => { Some(ConditionCode::LE) },
+            _ => None,
+        }
+    }
+}
+
+impl Default for Instruction {
+    fn default() -> Self {
+        Instruction::invalid()
+    }
+}
+
+impl Instruction {
+    pub fn operand(&self, i: u8) -> Operand {
+        assert!(i < 4);
+        Operand::from_spec(self, self.operands[i as usize])
+    }
+
+    pub fn operand_count(&self) -> u8 {
+        let mut i = 0;
+        for op in self.operands.iter() {
+            if let OperandSpec::Nothing = op {
+                return i;
+            } else {
+                i += 1;
+            }
+        }
+        return i;
+    }
+
+    pub fn operand_present(&self, i: u8) -> bool {
+        assert!(i < 4);
+        if let OperandSpec::Nothing = self.operands[i as usize] {
+            false
+        } else {
+            true
+        }
+    }
+
+    pub fn invalid() -> Instruction {
+        Instruction {
+            prefixes: Prefixes::new(0),
+            opcode: Opcode::Invalid,
+            modrm_rrr: RegSpec::eax(),
+            modrm_mmm: RegSpec::eax(), // doubles as sib_base
+            sib_index: RegSpec::eax(),
+            vex_reg: RegSpec::eax(),
+            scale: 0,
+            length: 0,
+            disp: 0,
+            imm: 0,
+            operand_count: 0,
+            operands: [OperandSpec::Nothing; 4],
+        }
+    }
+
+    pub fn is_invalid(&self) -> bool {
+        match self.opcode {
+            Opcode::Invalid => true,
+            _ => false
+        }
+    }
+
+    pub fn segment_override_for_op(&self, op: u8) -> Option<Segment> {
+        match self.opcode {
+            Opcode::STOS => {
+                if op == 0 {
+                    Some(Segment::ES)
+                } else {
+                    None
+                }
+            }
+            Opcode::LODS => {
+                if op == 1 {
+                    Some(self.prefixes.segment)
+                } else {
+                    None
+                }
+            }
+            Opcode::MOVS => {
+                if op == 0 {
+                    Some(Segment::ES)
+                } else if op == 1 {
+                    Some(self.prefixes.segment)
+                } else {
+                    None
+                }
+            }
+            Opcode::CMPS => {
+                if op == 0 {
+                    Some(self.prefixes.segment)
+                } else if op == 1 {
+                    Some(Segment::ES)
+                } else {
+                    None
+                }
+            },
+            _ => {
+                // most operands are pretty simple:
+                if self.operands[op as usize].is_memory() &&
+                    self.prefixes.segment != Segment::DS {
+                    Some(self.prefixes.segment)
+                } else {
+                    None
+                }
+            }
+        }
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct Prefixes {
+    bits: u8,
+    vex: PrefixVex,
+    segment: Segment,
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct PrefixVex {
+    bits: u8,
+}
+
+#[allow(dead_code)]
+impl PrefixVex {
+    #[inline]
+    fn b(&self) -> bool { (self.bits & 0x01) == 0x01 }
+    #[inline]
+    fn x(&self) -> bool { (self.bits & 0x02) == 0x02 }
+    #[inline]
+    fn r(&self) -> bool { (self.bits & 0x04) == 0x04 }
+    #[inline]
+    fn w(&self) -> bool { (self.bits & 0x08) == 0x08 }
+    #[inline]
+    fn l(&self) -> bool { (self.bits & 0x10) == 0x10 }
+    #[inline]
+    fn present(&self) -> bool { (self.bits & 0x80) == 0x80 }
+}
+
+#[allow(dead_code)]
+impl Prefixes {
+    fn new(bits: u8) -> Prefixes {
+        Prefixes {
+            bits: bits,
+            vex: PrefixVex {
+                bits: 0,
+            },
+            segment: Segment::DS,
+        }
+    }
+    fn vex_from(&mut self, bits: u8) {
+        self.vex = PrefixVex {
+            bits
+        };
+    }
+    #[inline]
+    fn rep(&self) -> bool { self.bits & 0x30 == 0x10 }
+    #[inline]
+    fn set_rep(&mut self) { self.bits = (self.bits & 0xcf) | 0x10 }
+    #[inline]
+    pub fn repz(&self) -> bool { self.bits & 0x30 == 0x20 }
+    #[inline]
+    fn set_repz(&mut self) { self.bits = (self.bits & 0xcf) | 0x20 }
+    #[inline]
+    pub fn repnz(&self) -> bool { self.bits & 0x30 == 0x30 }
+    #[inline]
+    fn set_repnz(&mut self) { self.bits = (self.bits & 0xcf) | 0x30 }
+    #[inline]
+    fn operand_size(&self) -> bool { self.bits & 0x1 == 1 }
+    #[inline]
+    fn set_operand_size(&mut self) { self.bits = self.bits | 0x1 }
+    #[inline]
+    fn address_size(&self) -> bool { self.bits & 0x2 == 2 }
+    #[inline]
+    fn set_address_size(&mut self) { self.bits = self.bits | 0x2 }
+    #[inline]
+    fn set_lock(&mut self) { self.bits |= 0x4 }
+    #[inline]
+    pub fn lock(&self) -> bool { self.bits & 0x4 == 4 }
+    #[inline]
+    fn cs(&mut self) { self.segment = Segment::CS }
+    #[inline]
+    fn set_cs(&mut self) { self.segment = Segment::CS }
+    #[inline]
+    pub fn ds(&self) -> bool { self.segment == Segment::DS }
+    #[inline]
+    fn set_ds(&mut self) { self.segment = Segment::DS }
+    #[inline]
+    pub fn es(&self) -> bool { self.segment == Segment::ES }
+    #[inline]
+    fn set_es(&mut self) { self.segment = Segment::ES }
+    #[inline]
+    pub fn fs(&self) -> bool { self.segment == Segment::FS }
+    #[inline]
+    fn set_fs(&mut self) { self.segment = Segment::FS }
+    #[inline]
+    pub fn gs(&self) -> bool { self.segment == Segment::GS }
+    #[inline]
+    fn set_gs(&mut self) { self.segment = Segment::GS }
+    #[inline]
+    pub fn ss(&self) -> bool { self.segment == Segment::SS }
+    #[inline]
+    fn set_ss(&mut self) { self.segment = Segment::SS }
+    #[inline]
+    fn vex(&self) -> PrefixVex { PrefixVex { bits: self.vex.bits } }
+
+    #[inline]
+    fn vex_from_c5(&mut self, bits: u8) {
+        // collect rex bits
+        let r = bits & 0x80;
+        let wrxb = (r >> 5) ^ 0x04;
+        let l = (bits & 0x04) << 2;
+        let synthetic_rex = wrxb | l | 0x80;
+        self.vex = PrefixVex { bits: synthetic_rex };
+    }
+
+    #[inline]
+    fn vex_from_c4(&mut self, high: u8, low: u8) {
+        let w = low & 0x80;
+        let rxb = (high >> 5) ^ 0x07;
+        let wrxb = rxb | w >> 4;
+        let l = (low & 0x04) << 2;
+        let synthetic_rex = wrxb | l | 0x80;
+        self.vex = PrefixVex { bits: synthetic_rex };
+    }
+}
+
+#[allow(non_camel_case_types)]
+// might be able to pack these into a u8, but with `Operand` being u16 as well now there's little
+// point. table entries will have a padding byte per record already.
+//
+// many of the one-off per-opcode variants could be written as 'decide based on opcode' but trying
+// to pack this more tightly only makes sense if opcode were smaller, to get some space savings.
+#[repr(u16)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub enum OperandCode {
+    ModRM_0x0f00,
+    ModRM_0x0f01,
+    ModRM_0x0fae,
+    ModRM_0x0fba,
+    ModRM_0xf238,
+    ModRM_0xf30fc7,
+    ModRM_0x660f38,
+    ModRM_0x660f3a,
+    CVT_AA,
+    CVT_DA,
+    Rq_Cq_0,
+    Rq_Dq_0,
+    Cq_Rq_0,
+    Dq_Rq_0,
+    FS,
+    GS,
+    Yb_DX,
+    Yv_DX,
+    DX_Xb,
+    DX_Xv,
+    AH,
+    AX_Xv,
+    // DX_AX,
+    E_G_xmm,
+    // Ev_Ivs,
+    Ew_Sw,
+    Fw,
+    I_3,
+    Ib,
+    Ibs,
+    Ivs,
+    Iw,
+    Iw_Ib,
+    Jvds,
+    Ob_AL,
+    Ov_AX,
+    Sw_Ew,
+    Yb_AL,
+    Yb_Xb,
+    Yv_AX,
+    Yv_Xv,
+    G_E_q,
+    E_G_q,
+    Rv_Gmm_Ib,
+    G_mm_Ew_Ib,
+    Mq_Dq,
+    ModRM_0x0f38,
+    ModRM_0x0f3a,
+    ModRM_0x0f71,
+    ModRM_0x0f72,
+    ModRM_0x0f73,
+    ModRM_0x660f12,
+    ModRM_0x660f16,
+    ModRM_0x660f71,
+    ModRM_0x660f72,
+    ModRM_0x660f73,
+    ModRM_0x660fc7,
+    ModRM_0x0fc7,
+    ModRM_0xc4,
+    ModRM_0xc5,
+    Nothing,
+    // Implied,
+    Unsupported,
+    AL_Ib = 0x100,
+    AX_Ib = 0x101,
+    Ib_AL = 0x102,
+    Ib_AX = 0x103,
+    AX_DX = 0x104,
+    AL_DX = 0x105,
+    DX_AX = 0x106,
+    DX_AL = 0x107,
+    MOVQ_f30f = 0x108,
+    G_xmm_Ed_Ib = 0x1ef, // mirror G_xmm_Edq, but also read an immediate
+    Zv_R0 = 0x40,
+    Zv_R1 = 0x41,
+    Zv_R2 = 0x42,
+    Zv_R3 = 0x43,
+    Zv_R4 = 0x44,
+    Zv_R5 = 0x45,
+    Zv_R6 = 0x46,
+    Zv_R7 = 0x47,
+    // Zv_AX_R0 = 0x48,
+    Zv_AX_R1 = 0x49,
+    Zv_AX_R2 = 0x4a,
+    Zv_AX_R3 = 0x4b,
+    Zv_AX_R4 = 0x4c,
+    Zv_AX_R5 = 0x4d,
+    Zv_AX_R6 = 0x4e,
+    Zv_AX_R7 = 0x4f,
+    Zb_Ib_R0 = 0x50,
+    Zb_Ib_R1 = 0x51,
+    Zb_Ib_R2 = 0x52,
+    Zb_Ib_R3 = 0x53,
+    Zb_Ib_R4 = 0x54,
+    Zb_Ib_R5 = 0x55,
+    Zb_Ib_R6 = 0x56,
+    Zb_Ib_R7 = 0x57,
+    Zv_Iv_R0 = 0x58,
+    Zv_Iv_R1 = 0x59,
+    Zv_Iv_R2 = 0x5a,
+    Zv_Iv_R3 = 0x5b,
+    Zv_Iv_R4 = 0x5c,
+    Zv_Iv_R5 = 0x5d,
+    Zv_Iv_R6 = 0x5e,
+    Zv_Iv_R7 = 0x5f,
+    Gv_Eb = 0x60,
+    Gv_Ew = 0x61,
+    Ew_Gw = 0x62,
+    G_E_mm_Ib = 0x64,
+    G_E_xmm_Ib = 0x65,
+    AL_Ibs = 0x66,
+    AX_Ivd = 0x67,
+    AL_Ob = 0x68,
+    AL_Xb = 0x69,
+    AX_AL = 0x6a,
+    AX_Ov = 0x6b,
+
+    Eb_Gb = 0x80,
+    Ev_Gv = 0x81,
+    Gb_Eb = 0xc2,
+    Gv_Ev = 0xc3,
+    Gb_Eb_Ib = 0xc4,
+    Gv_Ev_Iv = 0xc5,
+    // gap: 0xc6
+    Gd_U_xmm = 0xc7,
+    Gv_E_xmm = 0x1c7,
+    M_G_xmm = 0xc9,
+    ModRM_0x0f12 = 0xcb,
+    ModRM_0x0f16 = 0xce,
+    ModRM_0xc0_Eb_Ib = 0x86,
+    ModRM_0xc1_Ev_Ib = 0x87,
+    ModRM_0xd0_Eb_1 = 0x88,
+    ModRM_0xd1_Ev_1 = 0x89,
+    ModRM_0xd2_Eb_CL = 0x8a,
+    ModRM_0xd3_Ev_CL = 0x8b,
+    ModRM_0x80_Eb_Ib = 0x8c,
+    ModRM_0x83_Ev_Ibs = 0x8d,
+    // this would be Eb_Ivs, 0x8e
+    ModRM_0x81_Ev_Ivs = 0x8f,
+    ModRM_0xc6_Eb_Ib = 0x90,
+    ModRM_0xc7_Ev_Iv = 0x91,
+    ModRM_0xfe_Eb = 0x92,
+    ModRM_0x8f_Ev = 0x93,
+    // gap, 0x94
+    ModRM_0xff_Ev = 0x95,
+    ModRM_0xf6 = 0x96,
+    ModRM_0xf7 = 0x97,
+    Eb_R0 = 0x98,
+    Ev = 0x99,
+    ModRM_0x0f18 = 0x9b,
+    // gap, 0x9a
+    Gv_M = 0xdb,
+    G_mm_Edq = 0xdd,
+    G_mm_E = 0xdf,
+    G_U_xmm = 0xe1,
+    G_xmm_Ed = 0xe3,
+    G_mm_E_xmm = 0xe5,
+    G_E_mm = 0xe7,
+    Edq_G_mm = 0xe9,
+    Edq_G_xmm = 0x1e9,
+    E_G_mm = 0xeb,
+    G_xmm_E_mm = 0xed,
+    G_xmm_U_mm = 0x1ed,
+    U_mm_G_xmm = 0x2ed,
+    G_xmm_Edq = 0xef,
+    G_U_mm = 0xf1,
+    Ev_Gv_Ib = 0xf3,
+    Ev_Gv_CL = 0xf5,
+    G_M_xmm = 0xf7,
+    G_E_xmm = 0xf9,
+}
+
+fn base_opcode_map(v: u8) -> Opcode {
+    match v {
+        0 => Opcode::ADD,
+        1 => Opcode::OR,
+        2 => Opcode::ADC,
+        3 => Opcode::SBB,
+        4 => Opcode::AND,
+        5 => Opcode::SUB,
+        6 => Opcode::XOR,
+        7 => Opcode::CMP,
+        _ => { unsafe { unreachable_unchecked() } }
+    }
+}
+
+const BITWISE_OPCODE_MAP: [Opcode; 8] = [
+    Opcode::ROL,
+    Opcode::ROR,
+    Opcode::RCL,
+    Opcode::RCR,
+    Opcode::SHL,
+    Opcode::SHR,
+    Opcode::SAL,
+    Opcode::SAR
+];
+
+const OPCODE_660F_MAP: [OpcodeRecord; 256] = [
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x10
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVUPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVUPD), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660f12),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVLPD), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UNPCKLPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UNPCKHPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVHPD), OperandCode::ModRM_0x660f16),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVHPD), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x20
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVAPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVAPD), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPI2PD), OperandCode::G_xmm_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVNTPD), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTTPD2PI), OperandCode::G_mm_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPD2PI), OperandCode::G_mm_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UCOMISD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::COMISD), OperandCode::G_E_xmm),
+// 0x30
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660f38),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660f3a),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x40
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x50
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVMSKPD), OperandCode::Gd_U_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SQRTPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ANDPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ANDNPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ORPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XORPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADDPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MULPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPD2PS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPS2DQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUBPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MINPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DIVPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MAXPD), OperandCode::G_E_xmm),
+// 0x60
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLBW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLWD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLDQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PACKSSWB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPGTB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPGTW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPGTD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PACKUSWB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHBW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHWD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHDQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PACKSSDW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLQDQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHQDQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVD), OperandCode::G_xmm_Ed),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVDQA), OperandCode::G_E_xmm),
+// 0x70
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSHUFD), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660f71),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660f72),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660f73),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPEQB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPEQW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPEQD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::HADDPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::HSUBPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVD), OperandCode::Edq_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVDQA), OperandCode::E_G_xmm),
+// 0x80
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x90
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xa0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xb0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xc0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPPD), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PINSRW), OperandCode::G_xmm_Ed_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PEXTRW), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SHUFPD), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x660fc7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xd0
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADDSUBPD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRLW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRLD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRLQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULLW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVQ), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMOVMSKB), OperandCode::Gd_U_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBUSB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBUSW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMINUB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PAND), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDUSB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDUSW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMAXUB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PANDN), OperandCode::G_E_xmm),
+// 0xe0
+    OpcodeRecord(Interpretation::Instruction(Opcode::PAVGB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRAW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRAD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PAVGW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULHUW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULHW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTTPD2DQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVNTDQ), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBSB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBSW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMINSW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POR), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDSB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDSW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMAXSW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PXOR), OperandCode::G_E_xmm),
+// 0xf0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSLLW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSLLD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSLLQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULUDQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMADDWD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSADBW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MASKMOVDQU), OperandCode::G_U_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDB), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDW), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDQ), OperandCode::G_E_xmm),
+];
+
+fn read_opcode_660f_map<T: Iterator<Item=u8>>(bytes_iter: &mut T, length: &mut u8) -> Result<(OpcodeRecord, u8), DecodeError> {
+    bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| {
+        *length += 1;
+        (OPCODE_660F_MAP[b as usize], b)
+    })
+}
+
+const OPCODE_F20F_MAP: [OpcodeRecord; 256] = [
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x10
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSD), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVDDUP), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x20
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTSI2SD), OperandCode::G_xmm_Edq),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTTSD2SI), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTSD2SI), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x30
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xf238),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x40
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x50
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SQRTSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADDSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MULSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTSD2SS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUBSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MINSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DIVSD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MAXSD), OperandCode::G_E_xmm),
+// 0x60
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x70
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSHUFLW), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::HADDPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::HSUBPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x80
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x90
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xa0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xb0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xc0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPSD), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xd0
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADDSUBPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVDQ2Q), OperandCode::U_mm_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xe0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPD2DQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xf0
+    OpcodeRecord(Interpretation::Instruction(Opcode::LDDQU), OperandCode::G_M_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+];
+
+fn read_opcode_f20f_map<T: Iterator<Item=u8>>(bytes_iter: &mut T, length: &mut u8) -> Result<(OpcodeRecord, u8), DecodeError> {
+    bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| {
+        *length += 1;
+        (OPCODE_F20F_MAP[b as usize], b)
+    })
+}
+
+const OPCODE_F30F_MAP: [OpcodeRecord; 256] = [
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x10
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSS), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSLDUP), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSHDUP), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x20
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTSI2SS), OperandCode::G_xmm_Edq),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTTSS2SI), OperandCode::Gv_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTSS2SI), OperandCode::Gv_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x30
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x40
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x50
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SQRTSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RSQRTSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RCPSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADDSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MULSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTSS2SD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTTPS2DQ), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUBSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MINSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DIVSS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MAXSS), OperandCode::G_E_xmm),
+// 0x60
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVDQU), OperandCode::G_E_xmm),
+// 0x70
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSHUFHW), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVQ), OperandCode::MOVQ_f30f),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVDQU), OperandCode::E_G_xmm),
+// 0x80
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x90
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xa0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xb0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POPCNT), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xc0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPSS), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xf30fc7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xd0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVQ2DQ), OperandCode::G_xmm_U_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xe0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTDQ2PD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0xf0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+];
+
+fn read_opcode_f30f_map<T: Iterator<Item=u8>>(bytes_iter: &mut T, length: &mut u8) -> Result<(OpcodeRecord, u8), DecodeError> {
+    bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| {
+        *length += 1;
+        (OPCODE_F30F_MAP[b as usize], b)
+    })
+    /*
+    match bytes_iter.next() {
+        Some(b) => {
+            *length += 1;
+            match b {
+                0x10 => { instruction.opcode = Opcode::MOVSS; Some(OperandCode::G_E_xmm) },
+                0x11 => { instruction.opcode = Opcode::MOVSS; Some(OperandCode::E_G_xmm) },
+                0x12 => { instruction.opcode = Opcode::MOVSLDUP; Some(OperandCode::G_E_xmm) },
+                0x2a => { instruction.opcode = Opcode::CVTSI2SS; Some(OperandCode::G_E_xmm) },
+                0x2c => { instruction.opcode = Opcode::CVTTSS2SI; Some(OperandCode::G_E_xmm) },
+                0x2d => { instruction.opcode = Opcode::CVTSS2SI; Some(OperandCode::G_E_xmm) },
+                0x51 => { instruction.opcode = Opcode::SQRTSS; Some(OperandCode::G_E_xmm) },
+                0x58 => { instruction.opcode = Opcode::ADDSS; Some(OperandCode::G_E_xmm) },
+                0x59 => { instruction.opcode = Opcode::MULSS; Some(OperandCode::G_E_xmm) },
+                0x5a => { instruction.opcode = Opcode::CVTSS2SD; Some(OperandCode::G_E_xmm) },
+                0x5c => { instruction.opcode = Opcode::SUBSS; Some(OperandCode::G_E_xmm) },
+                0x5d => { instruction.opcode = Opcode::MINSS; Some(OperandCode::G_E_xmm) },
+                0x5e => { instruction.opcode = Opcode::DIVSS; Some(OperandCode::G_E_xmm) },
+                0x5f => { instruction.opcode = Opcode::MAXSS; Some(OperandCode::G_E_xmm) },
+                _ => {
+                    instruction.opcode = Opcode::Invalid;
+                    Some(OperandCode::Nothing)
+                }
+            }
+        }
+        None => {
+            None
+        }
+    }
+    */
+}
+const OPCODE_0F_MAP: [OpcodeRecord; 256] = [
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f00),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f01),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LAR), OperandCode::Gv_Ew),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LSL), OperandCode::Gv_M),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SYSCALL), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CLTS), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SYSRET), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INVD), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::WBINVD), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UD2), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x10
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVUPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVUPS), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f12),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVLPS), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UNPCKLPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UNPCKHPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f16),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVHPS), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f18),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Ev),
+// 0x20
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Rq_Cq_0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Rq_Dq_0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Cq_Rq_0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Dq_Rq_0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVAPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVAPS), OperandCode::E_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPI2PS), OperandCode::G_xmm_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVNTPS), OperandCode::M_G_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTTPS2PI), OperandCode::G_mm_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPS2PI), OperandCode::G_mm_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::UCOMISS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::COMISS), OperandCode::G_E_xmm),
+
+// 0x30
+    OpcodeRecord(Interpretation::Instruction(Opcode::WRMSR), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RDTSC), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RDMSR), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RDPMC), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SYSENTER), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SYSEXIT), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::GETSEC), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f38),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f3a),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+
+// 0x40
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVO), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVNO), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVB), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVNB), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVZ), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVNZ), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVNA), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVA), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVS), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVNS), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVP), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVNP), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVL), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVGE), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVLE), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMOVG), OperandCode::Gv_Ev),
+
+// 0x50
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVMSKPS), OperandCode::Gd_U_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SQRTPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RSQRTPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RCPPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ANDPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ANDNPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ORPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XORPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADDPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MULPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTPS2PD), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CVTDQ2PS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUBPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MINPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DIVPS), OperandCode::G_E_xmm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MAXPS), OperandCode::G_E_xmm),
+
+// 0x60
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLBW), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLWD), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKLDQ), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PACKSSWB), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPGTB), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPGTW), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPGTD), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PACKUSWB), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHBW), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHWD), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUNPCKHDQ), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PACKSSDW), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVD), OperandCode::G_mm_Edq),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVQ), OperandCode::G_mm_E),
+
+// 0x70
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSHUFW), OperandCode::G_E_mm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f71),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f72),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0f73),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPEQB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPEQW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PCMPEQD), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::EMMS), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::VMREAD), OperandCode::E_G_q),
+    OpcodeRecord(Interpretation::Instruction(Opcode::VMWRITE), OperandCode::G_E_q),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVD), OperandCode::Edq_G_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVQ), OperandCode::E_G_mm),
+
+// 0x80
+    OpcodeRecord(Interpretation::Instruction(Opcode::JO), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNO), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JB), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNB), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JZ), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNZ), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNA), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JA), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JS), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNS), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JP), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNP), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JL), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JGE), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JLE), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JG), OperandCode::Jvds),
+
+// 0x90
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETO), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETNO), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETB), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETAE), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETZ), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETNZ), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETBE), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETA), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETS), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETNS), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETP), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETNP), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETL), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETGE), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETLE), OperandCode::Eb_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SETG), OperandCode::Eb_R0),
+
+// 0xa0
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::FS),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::FS),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CPUID), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BT), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SHLD), OperandCode::Ev_Gv_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SHLD), OperandCode::Ev_Gv_CL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::GS),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::GS),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RSM), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BTS), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SHRD), OperandCode::Ev_Gv_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SHRD), OperandCode::Ev_Gv_CL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0fae),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IMUL), OperandCode::Gv_Ev),
+
+// 0xb0
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPXCHG), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPXCHG), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LSS), OperandCode::Gv_M),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BTR), OperandCode::E_G_q),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LFS), OperandCode::Gv_M),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LGS), OperandCode::Gv_M),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVZX_b), OperandCode::Gv_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVZX_w), OperandCode::Gv_Ew),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing), // JMPE, ITANIUM
+    OpcodeRecord(Interpretation::Instruction(Opcode::UD2E), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0fba),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BTC), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::TZCNT), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSR), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSX_b), OperandCode::Gv_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVSX_w), OperandCode::Gv_Ew),
+
+// 0xc0
+    OpcodeRecord(Interpretation::Instruction(Opcode::XADD), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XADD), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPPS), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVNTI), OperandCode::Mq_Dq),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PINSRW), OperandCode::G_mm_Ew_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PEXTRW), OperandCode::Rv_Gmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SHUFPS), OperandCode::G_E_xmm_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x0fc7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::BSWAP), OperandCode::Zv_R7),
+
+// 0xd0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRLW), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRLD), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRLQ), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDQ), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULLW), OperandCode::G_E_mm),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMOVMSKB), OperandCode::G_U_mm),
+
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBUSB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBUSW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMINUB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PAND), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDUSB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDUSW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMAXUB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PANDN), OperandCode::Unsupported),
+
+// 0xe0
+    OpcodeRecord(Interpretation::Instruction(Opcode::PAVGB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRAW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSRAD), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PAVGW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULHUW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULHW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVNTQ), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBSB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBSW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMINSW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POR), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDSB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDSW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMAXSW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PXOR), OperandCode::G_E_mm),
+// 0xf0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSLLW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSLLD), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSLLQ), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMULUDQ), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PMADDWD), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSADBW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MASKMOVQ), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBD), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PSUBQ), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDB), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDW), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PADDD), OperandCode::Unsupported),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+];
+fn read_opcode_0f_map<T: Iterator<Item=u8>>(bytes_iter: &mut T, length: &mut u8) -> Result<OpcodeRecord, DecodeError> {
+    bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| {
+        *length += 1;
+        OPCODE_0F_MAP[b as usize]
+    })
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+enum Interpretation {
+    Instruction(Opcode),
+    Prefix,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+// this should be a 32-byte struct..
+struct OpcodeRecord(Interpretation, OperandCode);
+
+#[test]
+fn opcode_record_size() {
+    // there are more than 256 opcodes...
+    assert_eq!(core::mem::size_of::<OpcodeRecord>(), 4);
+}
+
+const OPCODES: [OpcodeRecord; 256] = [
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADD), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADD), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADD), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADD), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADD), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADD), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OR), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OR), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OR), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OR), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OR), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OR), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADC), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADC), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADC), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADC), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADC), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ADC), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SBB), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SBB), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SBB), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SBB), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SBB), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SBB), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::AND), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::AND), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::AND), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::AND), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::AND), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::AND), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUB), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUB), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUB), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUB), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUB), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SUB), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XOR), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XOR), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XOR), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XOR), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XOR), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XOR), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMP), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMP), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMP), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMP), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMP), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMP), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+// 0x40:
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INC), OperandCode::Zv_R7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::DEC), OperandCode::Zv_R7),
+// 0x50:
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Zv_R7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POP), OperandCode::Zv_R7),
+// 0x60
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ARPL), OperandCode::Ew_Gw),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Ivs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IMUL), OperandCode::Gv_Ev_Iv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSH), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IMUL), OperandCode::Gb_Eb_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INS), OperandCode::Yb_DX),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INS), OperandCode::Yv_DX),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OUTS), OperandCode::DX_Xb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OUTS), OperandCode::DX_Xv),
+// 0x70
+    OpcodeRecord(Interpretation::Instruction(Opcode::JO), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNO), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JB), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNB), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JZ), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNZ), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNA), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JA), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JS), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNS), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JP), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JNP), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JL), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JGE), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JLE), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JG), OperandCode::Ibs),
+// 0x80
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x80_Eb_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x81_Ev_Ivs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x83_Ev_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::TEST), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::TEST), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Eb_Gb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Ev_Gv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Gb_Eb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Gv_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Ew_Sw),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LEA), OperandCode::Gv_M),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Sw_Ew),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0x8f_Ev),
+    OpcodeRecord(Interpretation::Instruction(Opcode::NOP), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::XCHG), OperandCode::Zv_AX_R7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::CVT_AA),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::CVT_DA),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::PUSHF), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::POPF), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SAHF), OperandCode::AH),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LAHF), OperandCode::AH),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::AL_Ob),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::AX_Ov),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Ob_AL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Ov_AX),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVS), OperandCode::Yb_Xb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOVS), OperandCode::Yv_Xv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPS), OperandCode::Yb_Xb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CMPS), OperandCode::Yv_Xv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::TEST), OperandCode::AL_Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::TEST), OperandCode::AX_Ivd),
+    OpcodeRecord(Interpretation::Instruction(Opcode::STOS), OperandCode::Yb_AL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::STOS), OperandCode::Yv_AX),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LODS), OperandCode::AL_Xb),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LODS), OperandCode::AX_Xv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SCAS), OperandCode::Yb_AL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::SCAS), OperandCode::Yv_AX),
+// 0xb0
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zb_Ib_R7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R0),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R2),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::Zv_Iv_R7),
+// 0xc0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xc0_Eb_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xc1_Ev_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RETURN), OperandCode::Iw),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RETURN), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LES), OperandCode::ModRM_0xc4),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LDS), OperandCode::ModRM_0xc5),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::ModRM_0xc6_Eb_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::MOV), OperandCode::ModRM_0xc7_Ev_Iv),
+    OpcodeRecord(Interpretation::Instruction(Opcode::ENTER), OperandCode::Iw_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::LEAVE), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RETF), OperandCode::Iw),
+    OpcodeRecord(Interpretation::Instruction(Opcode::RETF), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INT), OperandCode::I_3),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INT), OperandCode::Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::INTO), OperandCode::Fw),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IRET), OperandCode::Fw),
+// 0xd0
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xd0_Eb_1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xd1_Ev_1),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xd2_Eb_CL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xd3_Ev_CL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    // XLAT
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    // x86 d8
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 d9
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 da
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 db
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 dc
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 dd
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 de
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+    // x86 df
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Unsupported),
+// 0xe0
+    // LOOPNZ
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    // LOOPZ
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    // LOOP
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    // JECXZ
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IN), OperandCode::AL_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IN), OperandCode::AX_Ib),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OUT), OperandCode::Ib_AL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OUT), OperandCode::Ib_AX),
+// 0xe8
+    OpcodeRecord(Interpretation::Instruction(Opcode::CALL), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JMP), OperandCode::Jvds),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::JMP), OperandCode::Ibs),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IN), OperandCode::AL_DX),
+    OpcodeRecord(Interpretation::Instruction(Opcode::IN), OperandCode::AX_DX),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OUT), OperandCode::DX_AL),
+    OpcodeRecord(Interpretation::Instruction(Opcode::OUT), OperandCode::DX_AX),
+// 0xf0
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    // ICEBP?
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Prefix, OperandCode::Nothing),
+// 0xf4
+    OpcodeRecord(Interpretation::Instruction(Opcode::HLT), OperandCode::Nothing),
+    // CMC
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xf6),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xf7),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CLC), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::STC), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CLI), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::STI), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::CLD), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::STD), OperandCode::Nothing),
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xfe_Eb),
+    // TODO: test 0xff /3
+    OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::ModRM_0xff_Ev),
+];
+
+#[allow(non_snake_case)]
+pub(self) fn read_E<T: Iterator<Item=u8>>(bytes_iter: &mut T, instr: &mut Instruction, modrm: u8, width: u8, length: &mut u8) -> Result<OperandSpec, DecodeError> {
+    let bank = width_to_gp_reg_bank(width);
+    if modrm >= 0b11000000 {
+        read_modrm_reg(instr, modrm, bank)
+    } else {
+        read_M(bytes_iter, instr, modrm, length)
+    }
+}
+#[allow(non_snake_case)]
+pub(self) fn read_E_xmm<T: Iterator<Item=u8>>(bytes_iter: &mut T, instr: &mut Instruction, modrm: u8, length: &mut u8) -> Result<OperandSpec, DecodeError> {
+    if modrm >= 0b11000000 {
+        read_modrm_reg(instr, modrm, RegisterBank::X)
+    } else {
+        read_M(bytes_iter, instr, modrm, length)
+    }
+}
+#[allow(non_snake_case)]
+pub(self) fn read_E_ymm<T: Iterator<Item=u8>>(bytes_iter: &mut T, instr: &mut Instruction, modrm: u8, length: &mut u8) -> Result<OperandSpec, DecodeError> {
+    if modrm >= 0b11000000 {
+        read_modrm_reg(instr, modrm, RegisterBank::Y)
+    } else {
+        read_M(bytes_iter, instr, modrm, length)
+    }
+}
+
+#[allow(non_snake_case)]
+fn read_modrm_reg(instr: &mut Instruction, modrm: u8, reg_bank: RegisterBank) -> Result<OperandSpec, DecodeError> {
+    instr.modrm_mmm = RegSpec::from_parts(modrm & 7, reg_bank);
+    Ok(OperandSpec::RegMMM)
+}
+
+#[allow(non_snake_case)]
+fn read_sib<T: Iterator<Item=u8>>(bytes_iter: &mut T, instr: &mut Instruction, modrm: u8, length: &mut u8) -> Result<OperandSpec, DecodeError> {
+    let modbits = modrm >> 6;
+    let addr_width = if instr.prefixes.address_size() { RegisterBank::W } else { RegisterBank::D };
+    let sibbyte = bytes_iter.next().ok_or(DecodeError::ExhaustedInput)?;
+    *length += 1;
+
+    let op_spec = if (sibbyte & 7) == 0b101 {
+        let disp = if modbits == 0b00 {
+            *length += 4;
+            read_num(bytes_iter, 4)? as i32
+        } else if modbits == 0b01 {
+            *length += 1;
+            read_num(bytes_iter, 1)? as i8 as i32
+        } else {
+            *length += 4;
+            read_num(bytes_iter, 4)? as i32
+        };
+
+        if ((sibbyte >> 3) & 7) == 0b100 {
+            if modbits == 0b00 {
+                instr.disp = disp as u32;
+
+                OperandSpec::DispU32
+            } else {
+                let reg = RegSpec::from_parts(0b100, addr_width);
+                instr.modrm_mmm = reg;
+
+                if disp == 0 {
+                    OperandSpec::Deref
+                } else {
+                    instr.disp = disp as i32 as u32;
+                    OperandSpec::RegDisp
+                }
+            }
+        } else {
+            instr.modrm_mmm = RegSpec::from_parts(5, addr_width);
+
+            instr.sib_index = RegSpec::from_parts((sibbyte >> 3) & 7, addr_width);
+            let scale = 1u8 << (sibbyte >> 6);
+            instr.scale = scale;
+
+            if disp == 0 {
+                if modbits == 0 {
+                    OperandSpec::RegScale
+                } else {
+                    OperandSpec::RegIndexBaseScale
+                }
+            } else {
+                instr.disp = disp as i32 as u32;
+                if modbits == 0 {
+                    OperandSpec::RegScaleDisp
+                } else {
+                    OperandSpec::RegIndexBaseScaleDisp
+                }
+            }
+        }
+    } else {
+        instr.modrm_mmm = RegSpec::from_parts(sibbyte & 7, addr_width);
+
+        let disp = if modbits == 0b00 {
+            0
+        } else if modbits == 0b01 {
+            *length += 1;
+            read_num(bytes_iter, 1)? as i8 as i32
+        } else {
+            *length += 4;
+            read_num(bytes_iter, 4)? as i32
+        };
+
+        if ((sibbyte >> 3) & 7) == 0b100 {
+            if disp == 0 {
+                OperandSpec::Deref
+            } else {
+                instr.disp = disp as i32 as u32;
+                OperandSpec::RegDisp
+            }
+        } else {
+            instr.sib_index = RegSpec::from_parts((sibbyte >> 3) & 7, addr_width);
+            let scale = 1u8 << (sibbyte >> 6);
+            instr.scale = scale;
+            if disp == 0 {
+                OperandSpec::RegIndexBaseScale
+            } else {
+                instr.disp = disp as i32 as u32;
+                OperandSpec::RegIndexBaseScaleDisp
+            }
+        }
+    };
+    Ok(op_spec)
+}
+
+#[allow(non_snake_case)]
+fn read_M_16bit<T: Iterator<Item=u8>>(bytes_iter: &mut T, instr: &mut Instruction, modrm: u8, length: &mut u8) -> Result<OperandSpec, DecodeError> {
+    let modbits = modrm >> 6;
+    let mmm = modrm & 7;
+    if modbits == 0b00 && mmm == 0b110 {
+        return Ok(OperandSpec::DispU16);
+    }
+    match mmm {
+        0b000 => {
+            instr.modrm_mmm = RegSpec::bx();
+            instr.sib_index = RegSpec::si();
+        },
+        0b001 => {
+            instr.modrm_mmm = RegSpec::bx();
+            instr.sib_index = RegSpec::di();
+        },
+        0b010 => {
+            instr.modrm_mmm = RegSpec::bp();
+            instr.sib_index = RegSpec::si();
+        },
+        0b011 => {
+            instr.modrm_mmm = RegSpec::bp();
+            instr.sib_index = RegSpec::di();
+        },
+        0b100 => {
+            instr.modrm_mmm = RegSpec::si();
+        },
+        0b101 => {
+            instr.modrm_mmm = RegSpec::di();
+        },
+        0b110 => {
+            instr.modrm_mmm = RegSpec::bp();
+        },
+        0b111 => {
+            instr.modrm_mmm = RegSpec::bx();
+        },
+        _ => { unreachable!("impossible bit pattern"); }
+    }
+    match modbits {
+        0b00 => {
+            if mmm > 3 {
+                Ok(OperandSpec::Deref)
+            } else {
+                Ok(OperandSpec::RegIndexBase)
+            }
+        },
+        0b01 => {
+            instr.disp = read_num(bytes_iter, 1)?;
+            *length += 1;
+            if mmm > 3 {
+                Ok(OperandSpec::RegDisp)
+            } else {
+                Ok(OperandSpec::RegIndexBaseDisp)
+            }
+        },
+        0b10 => {
+            instr.disp = read_num(bytes_iter, 2)?;
+            *length += 2;
+            if mmm > 3 {
+                Ok(OperandSpec::RegDisp)
+            } else {
+                Ok(OperandSpec::RegIndexBaseDisp)
+            }
+        },
+        _ => {
+            unreachable!("read_M_16but but mod bits were not a memory operand");
+        }
+    }
+}
+
+#[allow(non_snake_case)]
+fn read_M<T: Iterator<Item=u8>>(bytes_iter: &mut T, instr: &mut Instruction, modrm: u8, length: &mut u8) -> Result<OperandSpec, DecodeError> {
+    if instr.prefixes.address_size() {
+        return read_M_16bit(bytes_iter, instr, modrm, length);
+    }
+    let addr_width = RegisterBank::D;
+    let modbits = modrm >> 6;
+    let mmm = modrm & 7;
+    let op_spec = if mmm == 4 {
+        return read_sib(bytes_iter, instr, modrm, length);
+    } else if mmm == 5 && modbits == 0b00 {
+        *length += 4;
+        instr.disp = read_num(bytes_iter, 4)? as u32;
+        OperandSpec::DispU32
+    } else {
+        instr.modrm_mmm = RegSpec::from_parts(mmm, addr_width);
+
+        if modbits == 0b00 {
+            OperandSpec::Deref
+        } else {
+            let disp = if modbits == 0b01 {
+                *length += 1;
+                read_num(bytes_iter, 1)? as i8 as i32
+            } else {
+                *length += 4;
+                read_num(bytes_iter, 4)? as i32
+            };
+            if disp == 0 {
+                OperandSpec::Deref
+            } else {
+                instr.disp = disp as i32 as u32;
+                OperandSpec::RegDisp
+            }
+        }
+    };
+    Ok(op_spec)
+}
+
+#[inline]
+fn width_to_gp_reg_bank(width: u8) -> RegisterBank {
+    match width {
+        1 => return RegisterBank::B,
+        2 => return RegisterBank::W,
+        4 => return RegisterBank::D,
+        o => { unreachable!("impossible width: {}", o); }
+//        _ => unsafe { unreachable_unchecked() }
+    }
+}
+
+fn read_instr<T: Iterator<Item=u8>>(decoder: &InstDecoder, mut bytes_iter: T, instruction: &mut Instruction) -> Result<(), DecodeError> {
+    let mut length = 0u8;
+    let mut alternate_opcode_map: Option<OpcodeMap> = None;
+//    use core::intrinsics::unlikely;
+    let mut prefixes = Prefixes::new(0);
+
+    fn escapes_are_prefixes_actually(prefixes: &mut Prefixes, opc_map: &mut Option<OpcodeMap>) {
+        match opc_map {
+            Some(OpcodeMap::Map66) => {
+                prefixes.set_operand_size();
+            },
+            Some(OpcodeMap::MapF2) => {
+                prefixes.set_repnz();
+            },
+            Some(OpcodeMap::MapF3) => {
+                prefixes.set_rep();
+            },
+            None => {}
+        }
+        *opc_map = None;
+    }
+
+    let record: OpcodeRecord = loop {
+//    let operand_code = loop {
+        match bytes_iter.next() {
+            Some(b) => {
+                length += 1;
+                let record = OPCODES[b as usize];
+                if b == 0x0f {
+                    let record = match alternate_opcode_map {
+                        Some(opcode_map) => {
+                            let (rec, opcode_byte) = match opcode_map {
+                                OpcodeMap::Map66 => {
+                                    read_opcode_660f_map(&mut bytes_iter, &mut length)?
+                                },
+                                OpcodeMap::MapF2 => {
+                                    read_opcode_f20f_map(&mut bytes_iter, &mut length)?
+                                },
+                                OpcodeMap::MapF3 => {
+                                    read_opcode_f30f_map(&mut bytes_iter, &mut length)?
+                                },
+                            };
+                            if rec == OpcodeRecord(Interpretation::Instruction(Opcode::Invalid), OperandCode::Nothing) {
+                                escapes_are_prefixes_actually(&mut prefixes, &mut Some(opcode_map));
+                                OPCODE_0F_MAP[opcode_byte as usize]
+                            } else {
+                                rec
+                            }
+                        },
+                        None => {
+                            read_opcode_0f_map(&mut bytes_iter, &mut length)?
+                        }
+                    };
+
+                    break record;
+                } else if let Interpretation::Instruction(_) = record.0 {
+                    escapes_are_prefixes_actually(&mut prefixes, &mut alternate_opcode_map);
+                    break record;
+                } else {
+                    escapes_are_prefixes_actually(&mut prefixes, &mut alternate_opcode_map);
+                    match b {
+                        0x26 => {
+                            prefixes.set_es();
+                        },
+                        0x2e => {
+                            prefixes.set_cs();
+                        },
+                        0x36 => {
+                            prefixes.set_ss();
+                        },
+                        0x3e => {
+                            prefixes.set_ds();
+                        },
+                        0x64 => {
+                            prefixes.set_fs();
+                        },
+                        0x65 => {
+                            prefixes.set_gs();
+                        },
+                        0x66 => {
+                            alternate_opcode_map = Some(OpcodeMap::Map66);
+                        },
+                        0x67 => {
+                            prefixes.set_address_size();
+                        },
+                        0x9b => {
+                            // TODO: WAIT prefix
+                            return Err(DecodeError::IncompleteDecoder);
+                        },
+                        0xf0 => {
+                            prefixes.set_lock();
+                        },
+                        0xf2 => {
+                            alternate_opcode_map = Some(OpcodeMap::MapF2);
+                        },
+                        0xf3 => {
+                            alternate_opcode_map = Some(OpcodeMap::MapF3);
+                        },
+//                        _ => { unsafe { unreachable_unchecked(); } }
+                        o => {
+                            unreachable!("invalid prefix {:#02x}", o);
+                        }
+                    }
+                }
+            },
+            None => {
+                return Err(DecodeError::ExhaustedInput);
+            }
+        }
+    };
+    if let Interpretation::Instruction(opcode) = record.0 {
+        instruction.opcode = opcode;
+    } else {
+//        unsafe { unreachable_unchecked(); }
+        unreachable!("bad record, needs to be an Instruction but was {:?}", record);
+    }
+    instruction.prefixes = prefixes;
+    read_operands(decoder, bytes_iter, instruction, record.1, &mut length)?;
+    instruction.length = length;
+
+    if decoder != &InstDecoder::default() {
+        // we might have to fix up or reject this instruction under whatever cpu features we need to
+        // pretend to have.
+        decoder.revise_instruction(instruction)?;
+    }
+    Ok(())
+}
+fn read_operands<T: Iterator<Item=u8>>(decoder: &InstDecoder, mut bytes_iter: T, instruction: &mut Instruction, operand_code: OperandCode, length: &mut u8) -> Result<(), DecodeError> {
+    if (operand_code as u8) & 0x40 == 0x40 {
+        instruction.operands[0] = OperandSpec::RegRRR;
+    }
+    if (operand_code as u8) >= 0x40 && (operand_code as u8) < 0x60 {
+        let reg = (operand_code as u8) & 0x07;
+        let category = ((operand_code as u8) & 0x18) >> 3;
+        if category == 0 {
+            // these are Zv_R
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let bank = if opwidth == 4 {
+                RegisterBank::D
+            } else {
+                RegisterBank::W
+            };
+            instruction.modrm_rrr =
+                RegSpec::from_parts(reg, bank);
+            instruction.operand_count = 1;
+        // Zv_AX are missing!
+        } else if category == 2 {
+            // these are Zb_Ib_R
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts(reg, 1);
+            instruction.imm =
+                read_imm_unsigned(&mut bytes_iter, 1, length)?;
+            instruction.operands[1] = OperandSpec::ImmU8;
+            instruction.operand_count = 2;
+        } else {
+            // category == 3, Zv_Iv_R
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let bank = if opwidth == 4 {
+                RegisterBank::D
+            } else {
+                RegisterBank::W
+            };
+            instruction.modrm_rrr =
+                RegSpec::from_parts(reg, bank);
+            instruction.imm =
+                read_num(&mut bytes_iter, opwidth)? as u32;
+            *length += opwidth;
+            instruction.operands[1] = match opwidth {
+                1 => OperandSpec::ImmI8,
+                2 => OperandSpec::ImmI16,
+                4 => OperandSpec::ImmI32,
+                o => unsafe { unreachable!("impossibe op width {}", o) }
+//                _ => unsafe { unreachable_unchecked() }
+            };
+            instruction.operand_count = 2;
+        }
+        return Ok(());
+    }
+
+    let mut modrm = 0;
+    let mut opwidth = 0;
+    let mut mem_oper = OperandSpec::Nothing;
+    let mut bank = RegisterBank::D;
+    let code_int = operand_code as u8;
+    if ((code_int) & 0x80) == 0x80 {
+        // cool! we can precompute opwidth and know we need to read_E.
+        if (code_int & 1) == 1 {
+            // further, this is an vd E
+            opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            if opwidth == 4 {
+                bank = RegisterBank::D;
+            } else if opwidth == 2 {
+                bank = RegisterBank::W;
+            }
+        } else {
+            opwidth = 1;
+            bank = RegisterBank::B;
+        };
+        modrm = read_modrm(&mut bytes_iter, length)?;
+        instruction.modrm_rrr =
+            RegSpec::from_parts((modrm >> 3) & 7, bank);
+
+        mem_oper = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+    }
+
+    let numeric_code = (operand_code as u8) & 0xbf;
+    if numeric_code >= 0x80 && numeric_code < 0x84 {
+        let (mmm, rrr) = if numeric_code & 0x02 == 2 {
+            (1, 0)
+        } else {
+            (0, 1)
+        };
+        instruction.operands[mmm] = mem_oper;
+        instruction.operands[rrr] = OperandSpec::RegRRR;
+        instruction.operand_count = 2;
+    } else if operand_code == OperandCode::Ibs {
+        instruction.imm =
+            read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+        instruction.operands[0] = OperandSpec::ImmI8;
+        instruction.operand_count = 1;
+    } else {
+    match operand_code {
+        /*
+        Gv_Ev_Iv,
+        Gb_Eb_Ib,
+        Yb_DX,
+        Yv_DX,
+        DX_Xb,
+        DX_Xv,
+        OR,
+        AH,
+        AL_Ib,
+        AL_Ob,
+        AL_Xb,
+        AX_AL,
+        AX_Ivd,
+        AX_Ov,
+        AX_Xv,
+        DX_AX,
+        Eb_1,
+        Eb_Ib,
+        Eb_CL,
+        Ev,
+        Ev_1,
+        Ev_CL,
+        Ev_Ibs,
+        Ev_Iv,
+        Ev_Ivs,
+        Ew_Sw,
+        Fw,
+        Gv_M,
+        I_3,
+        Ib,
+        Ibs,
+        Ivs,
+        Iw,
+        Iw_Ib,
+        Ob_AL,
+        Ov_AX,
+        Sw_Ew,
+        Yb_AL,
+        Yb_Xb,
+        Yv_AX,
+        Yv_Xv,
+        Zb_Ib,
+        Zv,
+        Zv_AX,
+        */
+        OperandCode::Eb_R0 => {
+            if (modrm & 0b00111000) != 0 {
+                instruction.opcode = Opcode::Invalid;
+                return Err(DecodeError::InvalidOperand); // Err("Invalid modr/m for opcode 0xc6".to_owned());
+            }
+
+            instruction.operands[0] = mem_oper;
+            instruction.operand_count = 1;
+        },
+        op @ OperandCode::AL_Ob |
+        op @ OperandCode::AX_Ov => {
+            let opwidth = match op {
+                OperandCode::AL_Ob => 1,
+                OperandCode::AX_Ov => {
+                    imm_width_from_prefixes(SizeCode::vd, instruction.prefixes)
+                }
+                _ => {
+                    unsafe { unreachable_unchecked() }
+                }
+            };
+            // stupid RCT thing:
+            let addr_width = if instruction.prefixes.address_size() { 2 } else { 4 };
+            let imm = read_num(&mut bytes_iter, addr_width)?;
+            *length += addr_width;
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts(0, opwidth);
+            instruction.disp = imm;
+            if instruction.prefixes.address_size() {
+                instruction.operands[1] = OperandSpec::DispU16;
+            } else {
+                instruction.operands[1] = OperandSpec::DispU32;
+            };
+            instruction.operand_count = 2;
+        }
+        op @ OperandCode::Ob_AL |
+        op @ OperandCode::Ov_AX => {
+            let opwidth = match op {
+                OperandCode::Ob_AL => 1,
+                OperandCode::Ov_AX => {
+                    imm_width_from_prefixes(SizeCode::vd, instruction.prefixes)
+                }
+                _ => {
+                    unsafe { unreachable_unchecked() }
+                }
+            };
+            let _addr_width = if instruction.prefixes.address_size() { 4 } else { 8 };
+            // stupid RCT thing:
+            let addr_width = if instruction.prefixes.address_size() { 2 } else { 4 };
+            let imm = read_num(&mut bytes_iter, addr_width)?;
+            *length += addr_width;
+            instruction.disp = imm;
+            instruction.operands[0] = if instruction.prefixes.address_size() {
+                OperandSpec::DispU32
+            } else {
+                OperandSpec::DispU16
+            };
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts(0, opwidth);
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        }
+        _op @ OperandCode::ModRM_0x80_Eb_Ib |
+        _op @ OperandCode::ModRM_0x81_Ev_Ivs => {
+            instruction.operands[0] = mem_oper;
+            let numwidth = if opwidth == 8 { 4 } else { opwidth };
+            instruction.imm = read_imm_signed(&mut bytes_iter, numwidth, length)? as u32;
+            instruction.opcode = base_opcode_map((modrm >> 3) & 7);
+            instruction.operands[1] = match opwidth {
+                1 => OperandSpec::ImmI8,
+                2 => OperandSpec::ImmI16,
+                4 => OperandSpec::ImmI32,
+                _ => unsafe { unreachable_unchecked() }
+            };
+            instruction.operand_count = 2;
+        },
+        OperandCode::ModRM_0xc4 => {
+            let modrm = bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| { *length += 1; b })?;
+            if modrm & 0b11000000 == 0b11000000 {
+                // interpret the c4 as a vex prefix
+                if instruction.prefixes.lock() || instruction.prefixes.operand_size() || instruction.prefixes.rep() || instruction.prefixes.repnz() {
+                    // prefixes and then vex is invalid! reject it.
+                    instruction.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidPrefixes);
+                } else {
+                    vex::three_byte_vex(&mut bytes_iter, modrm, instruction, *length)?;
+                    *length = instruction.length;
+
+                    if decoder != &InstDecoder::default() {
+                        decoder.revise_instruction(instruction)?;
+                    }
+                    return Ok(());
+                }
+            } else {
+                // LES
+                instruction.modrm_rrr = RegSpec::gp_from_parts((modrm >> 3) & 7, if instruction.prefixes.operand_size() { 2 } else { 4 });
+                instruction.operands[0] = OperandSpec::RegRRR;
+                instruction.operands[1] = read_M(&mut bytes_iter, instruction, modrm, length)?;
+            }
+        },
+        OperandCode::ModRM_0xc5 => {
+            let modrm = bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| { *length += 1; b })?;
+            if (modrm & 0b1100_0000) == 0b1100_0000 {
+                // interpret the c5 as a vex prefix
+                if instruction.prefixes.lock() || instruction.prefixes.operand_size() || instruction.prefixes.rep() || instruction.prefixes.repnz() {
+                    // prefixes and then vex is invalid! reject it.
+                    instruction.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidPrefixes);
+                } else {
+                    vex::two_byte_vex(&mut bytes_iter, modrm, instruction, *length)?;
+                    *length = instruction.length;
+
+                    if decoder != &InstDecoder::default() {
+                        decoder.revise_instruction(instruction)?;
+                    }
+                    return Ok(());
+                }
+            } else {
+                // LDS
+                instruction.modrm_rrr = RegSpec::gp_from_parts((modrm >> 3) & 7, if instruction.prefixes.operand_size() { 2 } else { 4 });
+                instruction.operands[0] = OperandSpec::RegRRR;
+                instruction.operands[1] = read_M(&mut bytes_iter, instruction, modrm, length)?;
+            }
+        },
+        _op @ OperandCode::ModRM_0xc6_Eb_Ib |
+        _op @ OperandCode::ModRM_0xc7_Ev_Iv => {
+            if (modrm & 0b00111000) != 0 {
+                instruction.opcode = Opcode::Invalid;
+                return Err(DecodeError::InvalidOperand); // Err("Invalid modr/m for opcode 0xc7".to_string());
+            }
+
+            instruction.operands[0] = mem_oper;
+            instruction.opcode = Opcode::MOV;
+            instruction.imm = read_imm_signed(&mut bytes_iter, opwidth, length)? as u32;
+            instruction.operands[1] = match opwidth {
+                1 => OperandSpec::ImmI8,
+                2 => OperandSpec::ImmI16,
+                4 => OperandSpec::ImmI32,
+                _ => unsafe { unreachable_unchecked() }
+            };
+            instruction.operand_count = 2;
+        },
+        op @ OperandCode::ModRM_0xc0_Eb_Ib |
+        op @ OperandCode::ModRM_0xc1_Ev_Ib |
+        op @ OperandCode::ModRM_0xd0_Eb_1 |
+        op @ OperandCode::ModRM_0xd1_Ev_1 |
+        op @ OperandCode::ModRM_0xd3_Ev_CL => {
+            instruction.operands[0] = mem_oper;
+            instruction.opcode = BITWISE_OPCODE_MAP[((modrm >> 3) & 7) as usize].clone();
+            if let OperandCode::ModRM_0xd3_Ev_CL = op {
+                instruction.modrm_rrr = RegSpec::cl();
+                instruction.operands[1] = OperandSpec::RegRRR;
+            } else {
+                let num = match op {
+                    OperandCode::ModRM_0xc0_Eb_Ib |
+                    OperandCode::ModRM_0xc1_Ev_Ib => {
+                        *length += 1;
+                        read_num(&mut bytes_iter, 1)?
+                    }
+                    _ => {
+                        // these are the _1 variants, everything else is unreachable
+                        1
+                    }
+                };
+                instruction.imm = num;
+                instruction.operands[1] = OperandSpec::ImmI8;
+            }
+            instruction.operand_count = 2;
+        },
+        _op @ OperandCode::ModRM_0xf6 |
+        _op @ OperandCode::ModRM_0xf7 => {
+            instruction.operands[0] = mem_oper;
+            instruction.operand_count = 1;
+            match (modrm >> 3) & 7 {
+                0 | 1 => {
+                    instruction.opcode = Opcode::TEST;
+                    instruction.imm = read_imm_signed(&mut bytes_iter, opwidth, length)? as u32;
+                    instruction.operands[1] = match opwidth {
+                        1 => OperandSpec::ImmI8,
+                        2 => OperandSpec::ImmI16,
+                        4 => OperandSpec::ImmI32,
+                        _ => unsafe { unreachable_unchecked() }
+                    };
+                    instruction.operand_count = 2;
+                },
+                2 => {
+                    instruction.opcode = Opcode::NOT;
+                },
+                3 => {
+                    instruction.opcode = Opcode::NEG;
+                },
+                4 => {
+                    instruction.opcode = Opcode::MUL;
+                },
+                5 => {
+                    instruction.opcode = Opcode::IMUL;
+                },
+                6 => {
+                    instruction.opcode = Opcode::DIV;
+                },
+                7 => {
+                    instruction.opcode = Opcode::IDIV;
+                },
+                _ => {
+                    unsafe { unreachable_unchecked(); }
+                }
+            }
+        },
+        OperandCode::ModRM_0xfe_Eb => {
+            instruction.operands[0] = mem_oper;
+            instruction.opcode = [
+                Opcode::INC,
+                Opcode::DEC,
+                Opcode::Invalid,
+                Opcode::Invalid,
+                Opcode::Invalid,
+                Opcode::Invalid,
+                Opcode::Invalid,
+                Opcode::Invalid
+            ][((modrm >> 3) & 7) as usize];
+            instruction.operand_count = 1;
+        }
+        OperandCode::ModRM_0xff_Ev => {
+            instruction.operands[0] = mem_oper;
+            let opcode = [
+                Opcode::INC,
+                Opcode::DEC,
+                Opcode::CALL,
+                Opcode::CALLF,
+                Opcode::JMP,
+                Opcode::JMPF,
+                Opcode::PUSH,
+                Opcode::Invalid
+            ][((modrm >> 3) & 7) as usize];
+            if instruction.operands[0] == OperandSpec::RegMMM {
+                if opcode == Opcode::CALL || opcode == Opcode::JMP {
+                    instruction.modrm_mmm.bank = RegisterBank::D;
+                } else if opcode == Opcode::CALLF || opcode == Opcode::JMPF {
+                    return Err(DecodeError::InvalidOperand);
+                }
+            }
+            instruction.opcode = opcode;
+            instruction.operand_count = 1;
+        }
+        OperandCode::Gv_Eb => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            instruction.operands[1] = read_E(&mut bytes_iter, instruction, modrm, 1, length)?;
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts((modrm >> 3) & 7, opwidth);
+            instruction.operand_count = 2;
+        },
+        OperandCode::Gv_Ew => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            instruction.operands[1] = read_E(&mut bytes_iter, instruction, modrm, 2, length)?;
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts((modrm >> 3) & 7, opwidth);
+            instruction.operand_count = 2;
+        },
+        OperandCode::Ew_Gw => {
+            let opwidth = 2;
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+//                println!("mod_bits: {:2b}, r: {:3b}, m: {:3b}", mod_bits, r, m);
+            instruction.operands[1] = instruction.operands[0];
+            instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts((modrm >> 3) & 7, opwidth);
+            instruction.operand_count = 2;
+        },
+        OperandCode::Ev => {
+            instruction.operands[0] = mem_oper;
+            instruction.operand_count = 1;
+        },
+        OperandCode::Gv_M => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts((modrm >> 3) & 7, opwidth);
+            instruction.operand_count = 2;
+        },
+        OperandCode::E_G_xmm => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+//                println!("mod_bits: {:2b}, r: {:3b}, m: {:3b}", mod_bits, r, m);
+            instruction.operands[0] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        },
+        OperandCode::G_E_mm => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::MM;
+            instruction.modrm_rrr.num &= 0b111;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::MM;
+                instruction.modrm_mmm.num &= 0b111;
+            }
+            instruction.operand_count = 2;
+        },
+        OperandCode::G_U_mm => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::D;
+            if mem_oper != OperandSpec::RegMMM {
+                return Err(DecodeError::InvalidOperand);
+            }
+            instruction.modrm_mmm.bank = RegisterBank::MM;
+            instruction.modrm_mmm.num &= 0b111;
+            instruction.operand_count = 2;
+        },
+        OperandCode::G_U_xmm => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper != OperandSpec::RegMMM {
+                return Err(DecodeError::InvalidOperand);
+            }
+            instruction.modrm_mmm.bank = RegisterBank::X;
+            instruction.operand_count = 2;
+        },
+        op @ OperandCode::G_M_xmm |
+        op @ OperandCode::G_E_xmm => {
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = mem_oper;
+            instruction.operand_count = 2;
+            if instruction.operands[1] == OperandSpec::RegMMM {
+                if op == OperandCode::G_M_xmm {
+                    instruction.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOperand);
+                } else {
+                    // fix the register to XMM
+                    instruction.modrm_mmm.bank = RegisterBank::X;
+                }
+            }
+        },
+        OperandCode::G_E_xmm_Ib => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)? as u8 as u32;
+            *length += 1;
+            instruction.operands[2] = OperandSpec::ImmI8;
+            instruction.operand_count = 3;
+        },
+        OperandCode::G_E_mm_Ib => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+//                println!("mod_bits: {:2b}, r: {:3b}, m: {:3b}", mod_bits, r, m);
+            instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+            instruction.modrm_rrr = RegSpec { bank: RegisterBank::MM, num: (modrm >> 3) & 7 };
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)? as u8 as u32;
+            *length += 1;
+            instruction.operands[2] = OperandSpec::ImmI8;
+            instruction.operand_count = 3;
+        },
+        OperandCode::G_mm_Ew_Ib => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+//                println!("mod_bits: {:2b}, r: {:3b}, m: {:3b}", mod_bits, r, m);
+            instruction.operands[1] = read_E(&mut bytes_iter, instruction, modrm, 4, length)?;
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::MM);
+            instruction.operands[0] = OperandSpec::RegRRR;
+            if instruction.operands[1] == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)? as u8 as u32;
+            *length += 1;
+            instruction.operands[2] = OperandSpec::ImmI8;
+            instruction.operand_count = 3;
+        }
+        OperandCode::AL_Ibs => {
+            instruction.modrm_rrr =
+                RegSpec::al();
+            instruction.imm =
+                read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmI8;
+            instruction.operand_count = 2;
+        }
+        OperandCode::AX_Ivd => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr =
+                RegSpec::gp_from_parts(0, opwidth);
+            instruction.imm =
+                read_imm_signed(&mut bytes_iter, opwidth, length)? as u32;
+            instruction.operands[1] = match opwidth {
+                2 => OperandSpec::ImmI16,
+                4 => OperandSpec::ImmI32,
+                _ => unsafe { unreachable_unchecked() }
+            };
+            instruction.operand_count = 2;
+        }
+        OperandCode::Ivs => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.imm =
+                read_imm_unsigned(&mut bytes_iter, opwidth, length)?;
+            instruction.operands[0] = match opwidth {
+                2 => OperandSpec::ImmI16,
+                4 => OperandSpec::ImmI32,
+                _ => unsafe { unreachable_unchecked() }
+            };
+            instruction.operand_count = 1;
+        },
+        OperandCode::ModRM_0x83_Ev_Ibs => {
+            instruction.operands[0] = mem_oper;
+            instruction.opcode = base_opcode_map((modrm >> 3) & 7);
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmI8;
+            instruction.operand_count = 2;
+        },
+        OperandCode::Jvds => {
+            let offset = read_num(&mut bytes_iter, 4)?;
+            *length += 4;
+            instruction.imm = offset;
+            instruction.operand_count = 1;
+            instruction.operands[0] = OperandSpec::ImmI32;
+        }
+        OperandCode::Gb_Eb_Ib => {
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = mem_oper;
+            instruction.imm =
+                read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[2] = OperandSpec::ImmI8;
+            instruction.operand_count = 3;
+        }
+        OperandCode::Gv_Ev_Iv => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let numwidth = if opwidth == 8 { 4 } else { opwidth };
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = mem_oper;
+            instruction.imm =
+                read_imm_signed(&mut bytes_iter, numwidth, length)? as u32;
+            instruction.operands[2] = match opwidth {
+                2 => OperandSpec::ImmI16,
+                4 => OperandSpec::ImmI32,
+                o => { unreachable!("impossible opwidth: {}", o); }
+//                _ => unsafe { unreachable_unchecked() }
+            };
+            instruction.operand_count = 3;
+        }
+        OperandCode::Ev_Gv_Ib => {
+            instruction.operands[0] = mem_oper;
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.imm =
+                read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[2] = OperandSpec::ImmI8;
+            instruction.operand_count = 3;
+        }
+        OperandCode::Ev_Gv_CL => {
+            instruction.operands[0] = mem_oper;
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operands[2] = OperandSpec::CL;
+            instruction.operand_count = 3;
+        }
+        OperandCode::Nothing => {
+            instruction.operand_count = 0;
+        }
+        _ => {
+            unlikely_operands(decoder, bytes_iter, instruction, operand_code, mem_oper, length)?;
+        }
+    };
+    }
+
+    Ok(())
+}
+fn unlikely_operands<T: Iterator<Item=u8>>(decoder: &InstDecoder, mut bytes_iter: T, instruction: &mut Instruction, operand_code: OperandCode, mem_oper: OperandSpec, length: &mut u8) -> Result<(), DecodeError> {
+    match operand_code {
+        OperandCode::Unsupported => {
+            return Err(DecodeError::IncompleteDecoder);
+        }
+        OperandCode::MOVQ_f30f => {
+            instruction.operand_count = 2;
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+        }
+        OperandCode::ModRM_0x0f71 => {
+            instruction.operand_count = 2;
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 != 0xc0 {
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                2 => {
+                    instruction.opcode = Opcode::PSRLW;
+                }
+                4 => {
+                    instruction.opcode = Opcode::PSRAW;
+                }
+                6 => {
+                    instruction.opcode = Opcode::PSLLW;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+
+            instruction.modrm_mmm = RegSpec { bank: RegisterBank::MM, num: modrm & 7 };
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmU8;
+        },
+        OperandCode::ModRM_0x0f72 => {
+            instruction.operand_count = 2;
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 != 0xc0 {
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                2 => {
+                    instruction.opcode = Opcode::PSRLD;
+                }
+                4 => {
+                    instruction.opcode = Opcode::PSRAD;
+                }
+                6 => {
+                    instruction.opcode = Opcode::PSLLD;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+
+            instruction.modrm_mmm = RegSpec { bank: RegisterBank::MM, num: modrm & 7 };
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmU8;
+        },
+        OperandCode::ModRM_0x0f73 => {
+            instruction.operand_count = 2;
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 != 0xc0 {
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                2 => {
+                    instruction.opcode = Opcode::PSRLQ;
+                }
+                6 => {
+                    instruction.opcode = Opcode::PSLLQ;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+
+            instruction.modrm_mmm = RegSpec { bank: RegisterBank::MM, num: modrm & 7 };
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmU8;
+        },
+        OperandCode::ModRM_0x660f12 => {
+            // If this is reg-reg, interpret the instruction as 66-prefixed (no-op here)
+            // `movhlps`. If this is reg-mem, it's a `movlpd`.
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 == 0xc0 {
+                instruction.opcode = Opcode::MOVHLPS;
+            } else {
+                instruction.opcode = Opcode::MOVLPD;
+            }
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+            instruction.operand_count = 2;
+        }
+        OperandCode::ModRM_0x660f16 => {
+            // If this is reg-reg, interpret the instruction as 66-prefixed (no-op here)
+            // `movlhps`. If this is reg-mem, it's a `movhpd`.
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 == 0xc0 {
+                instruction.opcode = Opcode::MOVLHPS;
+            } else {
+                instruction.opcode = Opcode::MOVHPD;
+            }
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+            instruction.operand_count = 2;
+        }
+        OperandCode::ModRM_0x660f38 => {
+            let op = bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| { *length += 1; b })?;
+            match op {
+                0xdb => { instruction.opcode = Opcode::AESIMC; }
+                0xdc => { instruction.opcode = Opcode::AESENC; }
+                0xdd => { instruction.opcode = Opcode::AESENCLAST; }
+                0xde => { instruction.opcode = Opcode::AESDEC; }
+                0xdf => { instruction.opcode = Opcode::AESDECLAST; }
+                _ => {
+                    instruction.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            };
+            // all these SO FAR are G_E_xmm
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            instruction.modrm_rrr =
+                RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+
+
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+            instruction.operand_count = 2;
+        }
+        OperandCode::ModRM_0x660f3a => {
+            let op = bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| { *length += 1; b })?;
+            match op {
+                0xdf => {
+                    instruction.opcode = Opcode::AESKEYGENASSIST;
+                    // read operands right here right now
+
+                    let modrm = read_modrm(&mut bytes_iter, length)?;
+                    instruction.modrm_rrr =
+                        RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
+
+
+                    instruction.operands[0] = OperandSpec::RegRRR;
+                    instruction.operands[1] = read_E_xmm(&mut bytes_iter, instruction, modrm, length)?;
+                    instruction.imm =
+                        read_imm_unsigned(&mut bytes_iter, 1, length)?;
+                    instruction.operands[2] = OperandSpec::ImmU8;
+                    instruction.operand_count = 3;
+                }
+                _ => {
+                    instruction.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            };
+        }
+        OperandCode::ModRM_0x660f71 => {
+            instruction.operand_count = 2;
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 != 0xc0 {
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                2 => {
+                    instruction.opcode = Opcode::PSRLW;
+                }
+                4 => {
+                    instruction.opcode = Opcode::PSRAW;
+                }
+                6 => {
+                    instruction.opcode = Opcode::PSLLW;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+
+            instruction.modrm_mmm = RegSpec { bank: RegisterBank::X, num: modrm & 7 };
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmU8;
+        },
+        OperandCode::ModRM_0x660f72 => {
+            instruction.operand_count = 2;
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 != 0xc0 {
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                2 => {
+                    instruction.opcode = Opcode::PSRLD;
+                }
+                4 => {
+                    instruction.opcode = Opcode::PSRAD;
+                }
+                6 => {
+                    instruction.opcode = Opcode::PSLLD;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+
+            instruction.modrm_mmm = RegSpec { bank: RegisterBank::X, num: modrm & 7 };
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmU8;
+        },
+        OperandCode::ModRM_0x660f73 => {
+            instruction.operand_count = 2;
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            if modrm & 0xc0 != 0xc0 {
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                2 => {
+                    instruction.opcode = Opcode::PSRLQ;
+                }
+                3 => {
+                    instruction.opcode = Opcode::PSRLDQ;
+                }
+                6 => {
+                    instruction.opcode = Opcode::PSLLQ;
+                }
+                7 => {
+                    instruction.opcode = Opcode::PSLLDQ;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+
+            instruction.modrm_mmm = RegSpec { bank: RegisterBank::X, num: modrm & 7 };
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as u32;
+            instruction.operands[1] = OperandSpec::ImmU8;
+        },
+        OperandCode::ModRM_0x660fc7 => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                6 => {
+                    instruction.opcode = Opcode::VMCLEAR;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, 1 /* doesn't matter, something using this width is invalid */, length)?;
+                    if instruction.operands[0] == OperandSpec::RegMMM {
+                        return Err(DecodeError::InvalidOperand);
+                    }
+                    instruction.operand_count = 1;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+        },
+        OperandCode::ModRM_0xf30fc7 => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            let r = (modrm >> 3) & 7;
+            match r {
+                6 => {
+                    instruction.opcode = Opcode::VMXON;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, 1 /* doesn't matter, something using this width is invalid */, length)?;
+                    if instruction.operands[0] == OperandSpec::RegMMM {
+                        return Err(DecodeError::InvalidOperand);
+                    }
+                    instruction.operand_count = 1;
+                }
+                _ => {
+                    return Err(DecodeError::InvalidOpcode);
+                }
+            }
+        },
+        OperandCode::G_mm_Edq => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::MM;
+            instruction.modrm_rrr.num &= 0b111;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        }
+        OperandCode::G_mm_E => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::MM;
+            instruction.modrm_rrr.num &= 0b111;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::MM;
+                instruction.modrm_mmm.num &= 0b111;
+            }
+        }
+        OperandCode::Edq_G_mm => {
+            instruction.operands[1] = instruction.operands[0];
+            instruction.operands[0] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::MM;
+            instruction.modrm_rrr.num &= 0b111;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        }
+        OperandCode::Edq_G_xmm => {
+            instruction.operands[1] = instruction.operands[0];
+            instruction.operands[0] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        }
+        OperandCode::E_G_mm => {
+            instruction.operands[1] = instruction.operands[0];
+            instruction.operands[0] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::MM;
+            instruction.modrm_rrr.num &= 0b111;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::MM;
+                instruction.modrm_mmm.num &= 0b111;
+            }
+        }
+        /*
+        OperandCode::G_xmm_Ed => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        },
+        */
+        OperandCode::G_xmm_Edq => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        },
+        OperandCode::G_xmm_Ed_Ib => {
+            instruction.operands[1] = mem_oper;
+            instruction.operands[2] = OperandSpec::ImmU8;
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)?;
+            *length += 1;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        },
+        OperandCode::G_xmm_Ed => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::D;
+            }
+        },
+        OperandCode::G_mm_E_xmm => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::MM;
+            instruction.modrm_rrr.num &= 0b111;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::X;
+            }
+        },
+        op @ OperandCode::G_xmm_U_mm |
+        op @ OperandCode::G_xmm_E_mm => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::MM;
+                instruction.modrm_mmm.num &= 0b111;
+            } else {
+                if op == OperandCode::G_xmm_U_mm {
+                    return Err(DecodeError::InvalidOperand);
+                }
+            }
+        },
+        OperandCode::U_mm_G_xmm => {
+            instruction.operands[1] = mem_oper;
+            instruction.modrm_mmm.bank = RegisterBank::X;
+            if mem_oper == OperandSpec::RegMMM {
+                instruction.modrm_rrr.bank = RegisterBank::MM;
+                instruction.modrm_rrr.num &= 0b111;
+            } else {
+                return Err(DecodeError::InvalidOperand);
+            }
+        }
+        // sure hope these aren't backwards huh
+        OperandCode::AL_Xb => {
+            instruction.operands[0] = OperandSpec::AL;
+            instruction.operands[1] = OperandSpec::Deref_esi;
+        }
+        // TODO: two memory operands! this is wrong!!!
+        OperandCode::Yb_Xb => {
+            instruction.operands[0] = OperandSpec::Deref_edi;
+            instruction.operands[1] = OperandSpec::Deref_esi;
+        }
+        OperandCode::Yb_AL => {
+            instruction.operands[0] = OperandSpec::Deref_edi;
+            instruction.operands[1] = OperandSpec::AL;
+        }
+        OperandCode::AX_Xv => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr = match opwidth {
+                2 => RegSpec::ax(),
+                4 => RegSpec::eax(),
+                _ => { unreachable!(); }
+            };
+            instruction.modrm_mmm = RegSpec::esi();
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = OperandSpec::Deref;
+        }
+        OperandCode::Yv_AX => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr = match opwidth {
+                2 => RegSpec::ax(),
+                4 => RegSpec::eax(),
+                _ => { unreachable!(); }
+            };
+            instruction.modrm_mmm = RegSpec::edi();
+            instruction.operands[0] = OperandSpec::Deref;
+            instruction.operands[1] = OperandSpec::RegRRR;
+        }
+        OperandCode::Yv_Xv => {
+            // TODO: repsect prefixes
+            instruction.operands[0] = OperandSpec::Deref_edi;
+            instruction.operands[1] = OperandSpec::Deref_esi;
+        }
+        OperandCode::ModRM_0x0f12 => {
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            instruction.operands[1] = mem_oper;
+            if instruction.operands[1] == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::X;
+                instruction.opcode = Opcode::MOVHLPS;
+            } else {
+                instruction.opcode = Opcode::MOVLPS;
+            }
+        }
+        OperandCode::ModRM_0x0f16 => {
+            instruction.modrm_rrr.bank = RegisterBank::X;
+            instruction.operands[1] = mem_oper;
+            if instruction.operands[1] == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::X;
+                instruction.opcode = Opcode::MOVLHPS;
+            } else {
+                instruction.opcode = Opcode::MOVHPS;
+            }
+        }
+        OperandCode::ModRM_0x0f18 => {
+            if mem_oper == OperandSpec::RegMMM {
+                return Err(DecodeError::InvalidOperand);
+            }
+            let rrr = instruction.modrm_rrr.num & 0b111;
+            instruction.operands[0] = mem_oper;
+            instruction.opcode = match rrr {
+                0 => Opcode::PREFETCHNTA,
+                1 => Opcode::PREFETCH0,
+                2 => Opcode::PREFETCH1,
+                3 => Opcode::PREFETCH2,
+                _ => Opcode::NOP,
+            };
+        }
+        OperandCode::Gd_U_xmm => {
+            instruction.operands[1] = mem_oper;
+            if instruction.operands[1] != OperandSpec::RegMMM {
+                instruction.opcode = Opcode::Invalid;
+                return Err(DecodeError::InvalidOperand);
+            }
+            instruction.modrm_rrr.bank = RegisterBank::D;
+            instruction.modrm_mmm.bank = RegisterBank::X;
+        }
+        OperandCode::Gv_E_xmm => {
+            instruction.operands[1] = mem_oper;
+            if instruction.operands[1] == OperandSpec::RegMMM {
+                instruction.modrm_mmm.bank = RegisterBank::X;
+            }
+        }
+        OperandCode::M_G_xmm => {
+            instruction.operands[1] = instruction.operands[0];
+            instruction.operands[0] = mem_oper;
+            if instruction.operands[0] == OperandSpec::RegMMM {
+                instruction.opcode = Opcode::Invalid;
+                return Err(DecodeError::InvalidOperand);
+            }
+            instruction.modrm_rrr.bank = RegisterBank::X;
+        }
+        OperandCode::Ew_Sw => {
+            let opwidth = 2;
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            // check r
+            if ((modrm >> 3) & 7) > 5 {
+                // return Err(()); //Err("Invalid r".to_owned());
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            instruction.modrm_rrr =
+                RegSpec { bank: RegisterBank::S, num: (modrm >> 3) & 7 };
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+
+            let mod_bits = modrm >> 6;
+            if mod_bits == 0b11 {
+                instruction.modrm_mmm =
+                    RegSpec { bank: RegisterBank::W, num: modrm & 7};
+                instruction.operands[0] = OperandSpec::RegMMM;
+            } else {
+                instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+            }
+        },
+        OperandCode::Sw_Ew => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+
+            // check r
+            if ((modrm >> 3) & 7) > 5 {
+                // return Err(()); // Err("Invalid r".to_owned());
+                return Err(DecodeError::InvalidOperand);
+            }
+
+            instruction.modrm_rrr =
+                RegSpec { bank: RegisterBank::S, num: (modrm >> 3) & 7 };
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+
+            let mod_bits = modrm >> 6;
+            if mod_bits == 0b11 {
+                instruction.modrm_mmm =
+                    RegSpec { bank: RegisterBank::W, num: modrm & 7};
+                instruction.operands[1] = OperandSpec::RegMMM;
+            } else {
+                instruction.operands[1] = read_M(&mut bytes_iter, instruction, modrm, length)?;
+            }
+        },
+        OperandCode::CVT_AA => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.opcode = match opwidth {
+                2 => { Opcode::CBW },
+                4 => { Opcode::CWDE },
+                _ => { unreachable!("invalid operation width"); },
+            }
+        }
+        OperandCode::CVT_DA => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.opcode = match opwidth {
+                2 => { Opcode::CBD },
+                4 => { Opcode::CDQ },
+                _ => { unreachable!("invalid operation width"); },
+            }
+        }
+        OperandCode::Ib => {
+            instruction.imm =
+                read_imm_unsigned(&mut bytes_iter, 1, length)?;
+            instruction.operands[0] = OperandSpec::ImmU8;
+            instruction.operand_count = 1;
+        }
+        OperandCode::Iw => {
+            instruction.imm =
+                read_imm_unsigned(&mut bytes_iter, 2, length)?;
+            instruction.operands[0] = OperandSpec::ImmU16;
+            instruction.operand_count = 1;
+        }
+        OperandCode::ModRM_0x0f00 => {
+            instruction.operand_count = 1;
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            let r = (modrm >> 3) & 7;
+            if r == 0 {
+                instruction.opcode = Opcode::SLDT;
+            } else if r == 1 {
+                instruction.opcode = Opcode::STR;
+            } else if r == 2 {
+                instruction.opcode = Opcode::LLDT;
+            } else if r == 3 {
+                instruction.opcode = Opcode::LTR;
+            } else if r == 4 {
+                instruction.opcode = Opcode::VERR;
+            } else if r == 5 {
+                instruction.opcode = Opcode::VERW;
+            } else if r == 6 {
+                instruction.opcode = Opcode::JMPE;
+                instruction.operand_count = 0;
+                return Ok(());
+            } else if r == 7 {
+                instruction.opcode = Opcode::Invalid;
+                instruction.operand_count = 0;
+                return Err(DecodeError::InvalidOperand);
+            } else {
+                unreachable!("r <= 8");
+            }
+            instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, 2, length)?;
+        }
+        OperandCode::ModRM_0x0f01 => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            let r = (modrm >> 3) & 7;
+            if r == 0 {
+                let mod_bits = modrm >> 6;
+                let m = modrm & 7;
+                if mod_bits == 0b11 {
+                    instruction.operand_count = 0;
+                    match m {
+                        0b000 => {
+                            instruction.opcode = Opcode::ENCLV;
+                        },
+                        0b001 => {
+                            instruction.opcode = Opcode::VMCALL;
+                        },
+                        0b010 => {
+                            instruction.opcode = Opcode::VMLAUNCH;
+                        },
+                        0b011 => {
+                            instruction.opcode = Opcode::VMRESUME;
+                        },
+                        0b100 => {
+                            instruction.opcode = Opcode::VMXOFF;
+                        },
+                        _ => {
+                            instruction.opcode = Opcode::Invalid;
+                            return Err(DecodeError::InvalidOpcode);
+                        }
+                    }
+                } else {
+                    instruction.opcode = Opcode::SGDT;
+                    instruction.operand_count = 1;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+                }
+            } else if r == 1 {
+                let mod_bits = modrm >> 6;
+                let m = modrm & 7;
+                if mod_bits == 0b11 {
+                    instruction.operand_count = 0;
+                    match m {
+                        0b000 => {
+                            instruction.opcode = Opcode::MONITOR;
+                        }
+                        0b001 => {
+                            instruction.opcode = Opcode::MWAIT;
+                        },
+                        0b010 => {
+                            instruction.opcode = Opcode::CLAC;
+                        }
+                        0b011 => {
+                            instruction.opcode = Opcode::STAC;
+                        }
+                        0b111 => {
+                            instruction.opcode = Opcode::ENCLS;
+                        }
+                        _ => {
+                            instruction.opcode = Opcode::Invalid;
+                            return Err(DecodeError::InvalidOpcode);
+                        }
+                    }
+                } else {
+                    instruction.opcode = Opcode::SIDT;
+                    instruction.operand_count = 1;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+                }
+            } else if r == 2 {
+                let mod_bits = modrm >> 6;
+                let m = modrm & 7;
+                if mod_bits == 0b11 {
+                    instruction.operand_count = 0;
+                    match m {
+                        0b000 => {
+                            instruction.opcode = Opcode::XGETBV;
+                        }
+                        0b001 => {
+                            instruction.opcode = Opcode::XSETBV;
+                        }
+                        0b100 => {
+                            instruction.opcode = Opcode::VMFUNC;
+                        }
+                        0b101 => {
+                            instruction.opcode = Opcode::XEND;
+                        }
+                        0b110 => {
+                            instruction.opcode = Opcode::XTEST;
+                        }
+                        0b111 => {
+                            instruction.opcode = Opcode::ENCLU;
+                        }
+                        _ => {
+                            instruction.opcode = Opcode::Invalid;
+                            return Err(DecodeError::InvalidOpcode);
+                        }
+                    }
+                } else {
+                    instruction.opcode = Opcode::LGDT;
+                    instruction.operand_count = 1;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+                }
+            } else if r == 3 {
+                let mod_bits = modrm >> 6;
+                if mod_bits == 0b11 {
+                    instruction.opcode = Opcode::Invalid;
+                    instruction.operand_count = 0;
+                    return Err(DecodeError::InvalidOperand);
+                } else {
+                    instruction.opcode = Opcode::LIDT;
+                    instruction.operand_count = 1;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+                }
+            } else if r == 4 {
+                // TODO: this permits storing only to word-size registers
+                // spec suggets this might do something different for f.ex edi?
+                instruction.opcode = Opcode::SMSW;
+                instruction.operand_count = 1;
+                instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, 2, length)?;
+            } else if r == 5 {
+                let m = modrm & 7;
+                match m {
+                    0b110 => {
+                        instruction.opcode = Opcode::RDPKRU;
+                        instruction.operand_count = 1;
+                    }
+                    0b111 => {
+                        instruction.opcode = Opcode::WRPKRU;
+                        instruction.operand_count = 1;
+                    }
+                    _ => {
+                        instruction.opcode = Opcode::Invalid;
+                        instruction.operand_count = 0;
+                        return Err(DecodeError::InvalidOpcode);
+                    }
+                }
+            } else if r == 6 {
+                instruction.opcode = Opcode::LMSW;
+                instruction.operand_count = 1;
+                instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, 2, length)?;
+            } else if r == 7 {
+                let mod_bits = modrm >> 6;
+                let m = modrm & 7;
+                if mod_bits == 0b11 {
+                    if m == 0 {
+                        instruction.opcode = Opcode::SWAPGS;
+                        instruction.operand_count = 0;
+                    } else if m == 1 {
+                        instruction.opcode = Opcode::RDTSCP;
+                        instruction.operand_count = 0;
+                    } else {
+                        instruction.opcode = Opcode::Invalid;
+                        return Err(DecodeError::InvalidOpcode);
+                    }
+                } else {
+                    instruction.opcode = Opcode::INVLPG;
+                    instruction.operand_count = 1;
+                    instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+                }
+            } else {
+                unreachable!("r <= 8");
+            }
+        }
+        OperandCode::ModRM_0x0fae => {
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            let r = (modrm >> 3) & 7;
+            let mod_bits = modrm >> 6;
+
+            // all the 0b11 instructions are err or no-operands
+            if mod_bits == 0b11 {
+                instruction.operand_count = 0;
+                let m = modrm & 7;
+                match r {
+                    // invalid rrr for 0x0fae, mod: 11
+                    0 | 1 | 2 | 3 | 4 => {
+                        return Err(DecodeError::InvalidOpcode);
+                    },
+                    5 => {
+                        instruction.opcode = Opcode::LFENCE;
+                        // Intel's manual accepts m != 0, AMD supports m != 0 though the manual
+                        // doesn't say (tested on threadripper)
+                        if !decoder.amd_quirks() && !decoder.intel_quirks() {
+                            if m != 0 {
+                                instruction.opcode = Opcode::Invalid;
+                                return Err(DecodeError::InvalidOperand);
+                            }
+                        }
+                    },
+                    6 => {
+                        instruction.opcode = Opcode::MFENCE;
+                        // Intel's manual accepts m != 0, AMD supports m != 0 though the manual
+                        // doesn't say (tested on threadripper)
+                        if !decoder.amd_quirks() && !decoder.intel_quirks() {
+                            if m != 0 {
+                                instruction.opcode = Opcode::Invalid;
+                                return Err(DecodeError::InvalidOperand);
+                            }
+                        }
+                    },
+                    7 => {
+                        instruction.opcode = Opcode::SFENCE;
+                        // Intel's manual accepts m != 0, AMD supports m != 0 though the manual
+                        // doesn't say (tested on threadripper)
+                        if !decoder.amd_quirks() && !decoder.intel_quirks() {
+                            if m != 0 {
+                                instruction.opcode = Opcode::Invalid;
+                                return Err(DecodeError::InvalidOperand);
+                            }
+                        }
+                    },
+                    _ => { unsafe { unreachable_unchecked() } /* r <=7 */ }
+                }
+            } else {
+                instruction.operand_count = 1;
+                instruction.opcode = [
+                    Opcode::FXSAVE,
+                    Opcode::FXRSTOR,
+                    Opcode::LDMXCSR,
+                    Opcode::STMXCSR,
+                    Opcode::XSAVE,
+                    Opcode::XRSTOR,
+                    Opcode::XSAVEOPT,
+                    Opcode::CLFLUSH,
+                ][r as usize];
+                instruction.operands[0] = read_M(&mut bytes_iter, instruction, modrm, length)?;
+            }
+        }
+        OperandCode::ModRM_0x0fba => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            let r = (modrm >> 3) & 7;
+            match r {
+                0 | 1 | 2 | 3 => {
+                    instruction.opcode = Opcode::Invalid;
+                    return Err(DecodeError::InvalidOpcode);
+                },
+                4 => {
+                    instruction.opcode = Opcode::BT;
+                }
+                5 => {
+                    instruction.opcode = Opcode::BTS;
+                }
+                6 => {
+                    instruction.opcode = Opcode::BTR;
+                }
+                7 => {
+                    instruction.opcode = Opcode::BTC;
+                }
+                _ => {
+                    unreachable!("r < 8");
+                }
+            }
+
+            instruction.operands[0] = read_E(&mut bytes_iter, instruction, modrm, opwidth, length)?;
+
+            instruction.imm = read_imm_signed(&mut bytes_iter, 1, length)? as i8 as i32 as u32;
+            instruction.operands[1] = OperandSpec::ImmI8;
+            instruction.operand_count = 2;
+        }
+        op @ OperandCode::Rq_Cq_0 |
+        op @ OperandCode::Rq_Dq_0 |
+        op @ OperandCode::Cq_Rq_0 |
+        op @ OperandCode::Dq_Rq_0 => {
+            let bank = match op {
+                OperandCode::Rq_Cq_0 |
+                OperandCode::Cq_Rq_0 => RegisterBank::CR,
+                OperandCode::Rq_Dq_0 |
+                OperandCode::Dq_Rq_0 => RegisterBank::DR,
+                _ => unsafe { unreachable_unchecked() }
+            };
+            let (rrr, mmm) = match op {
+                OperandCode::Rq_Cq_0 |
+                OperandCode::Rq_Dq_0 => (1, 0),
+                OperandCode::Cq_Rq_0 |
+                OperandCode::Dq_Rq_0 => (0, 1),
+                _ => unsafe { unreachable_unchecked() }
+            };
+
+            let modrm = read_modrm(&mut bytes_iter, length)?;
+            let m = modrm & 7;
+            let r = (modrm >> 3) & 7;
+            instruction.modrm_rrr =
+                RegSpec { bank: bank, num: r };
+            instruction.modrm_mmm =
+                RegSpec { bank: RegisterBank::D, num: m };
+            instruction.operands[mmm] = OperandSpec::RegMMM;
+            instruction.operands[rrr] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        }
+        OperandCode::FS => {
+            instruction.modrm_rrr = RegSpec::fs();
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operand_count = 1;
+        }
+        OperandCode::GS => {
+            instruction.modrm_rrr = RegSpec::gs();
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operand_count = 1;
+        }
+        OperandCode::I_3 => {
+            instruction.imm = 3;
+            instruction.operands[0] = OperandSpec::ImmU8;
+            instruction.operand_count = 1;
+        }
+        OperandCode::AL_Ib => {
+            instruction.modrm_rrr =
+                RegSpec::al();
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)?;
+            *length += 1;
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = OperandSpec::ImmU8;
+            instruction.operand_count = 2;
+        }
+        OperandCode::AX_Ib => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr = if opwidth == 4 {
+               RegSpec::eax()
+            } else {
+               RegSpec::ax()
+            };
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)?;
+            *length += 1;
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = OperandSpec::ImmU8;
+            instruction.operand_count = 2;
+        }
+        OperandCode::Ib_AL => {
+            instruction.modrm_rrr =
+                RegSpec::al();
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)?;
+            *length += 1;
+            instruction.operands[0] = OperandSpec::ImmU8;
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        }
+        OperandCode::Ib_AX => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr = if opwidth == 4 {
+                RegSpec::eax()
+            } else {
+                RegSpec::ax()
+            };
+            instruction.imm =
+                read_num(&mut bytes_iter, 1)?;
+            *length += 1;
+            instruction.operands[0] = OperandSpec::ImmU8;
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        }
+        OperandCode::AX_DX => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr = if opwidth == 4 {
+                RegSpec::eax()
+            } else {
+                RegSpec::ax()
+            };
+            instruction.modrm_mmm = RegSpec::dx();
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = OperandSpec::RegMMM;
+            instruction.operand_count = 2;
+        }
+        OperandCode::AL_DX => {
+            instruction.modrm_rrr = RegSpec::al();
+            instruction.modrm_mmm = RegSpec::dx();
+            instruction.operands[0] = OperandSpec::RegRRR;
+            instruction.operands[1] = OperandSpec::RegMMM;
+            instruction.operand_count = 2;
+        }
+        OperandCode::DX_AX => {
+            let opwidth = imm_width_from_prefixes(SizeCode::vd, instruction.prefixes);
+            instruction.modrm_rrr = if opwidth == 4 {
+                RegSpec::eax()
+            } else {
+                RegSpec::ax()
+            };
+            instruction.modrm_mmm = RegSpec::dx();
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        }
+        OperandCode::DX_AL => {
+            instruction.modrm_rrr = RegSpec::al();
+            instruction.modrm_mmm = RegSpec::dx();
+            instruction.operands[0] = OperandSpec::RegMMM;
+            instruction.operands[1] = OperandSpec::RegRRR;
+            instruction.operand_count = 2;
+        }
+        _ => {
+            instruction.operand_count = 0;
+            instruction.opcode = Opcode::Invalid;
+//            return Err(()); // Err(format!("unsupported operand code: {:?}", operand_code));
+            return Err(DecodeError::InvalidOperand);
+        }
+    };
+    Ok(())
+}
+
+fn decode_one<'b, T: IntoIterator<Item=u8>>(decoder: &InstDecoder, bytes: T, instr: &'b mut Instruction) -> Result<(), DecodeError> {
+    instr.operands = [
+        OperandSpec::Nothing,
+        OperandSpec::Nothing,
+        OperandSpec::Nothing,
+        OperandSpec::Nothing,
+    ];
+    let bytes_iter = bytes.into_iter();
+    read_instr(decoder, bytes_iter, instr)
+}
+
+#[inline]
+fn read_num<T: Iterator<Item=u8>>(bytes: &mut T, width: u8) -> Result<u32, DecodeError> {
+    let mut result = 0u32;
+    let mut idx = 0;
+    loop {
+        if idx == width {
+            return Ok(result);
+        }
+        let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?;
+        result |= (byte as u32) << (idx * 8);
+        idx += 1;
+    }
+}
+
+#[inline]
+fn read_imm_signed<T: Iterator<Item=u8>>(bytes: &mut T, num_width: u8, length: &mut u8) -> Result<i32, DecodeError> {
+    if num_width == 1 {
+        *length += 1;
+        Ok(read_num(bytes, 1)? as i8 as i32)
+    } else if num_width == 2 {
+        *length += 2;
+        Ok(read_num(bytes, 2)? as i16 as i32)
+    } else {
+        *length += 4;
+        Ok(read_num(bytes, 4)? as i32)
+    }
+}
+
+#[inline]
+fn read_imm_unsigned<T: Iterator<Item=u8>>(bytes: &mut T, width: u8, length: &mut u8) -> Result<u32, DecodeError> {
+    read_num(bytes, width).map(|res| {
+        *length += width;
+        res
+    })
+}
+
+#[inline]
+fn imm_width_from_prefixes(interpretation: SizeCode, prefixes: Prefixes) -> u8 {
+    match interpretation {
+        SizeCode::b => 1,
+        SizeCode::vd => {
+            if prefixes.operand_size() { 2 } else { 4 }
+        },
+    }
+}
+
+#[inline]
+fn read_modrm<T: Iterator<Item=u8>>(bytes_iter: &mut T, length: &mut u8) -> Result<u8, DecodeError> {
+    bytes_iter.next().ok_or(DecodeError::ExhaustedInput).map(|b| { *length += 1; b })
+}