diff options
| author | iximeow <me@iximeow.net> | 2020-01-28 01:13:07 -0800 |
|---|---|---|
| committer | iximeow <me@iximeow.net> | 2020-01-28 01:15:31 -0800 |
| commit | 87ac71fd89bd0dda7ee0e7b74f11c381718e4f84 (patch) | |
| tree | 963389985b36fad40114aa8c6bf212e99c6336c8 /src | |
draw the owl
Diffstat (limited to 'src')
| -rw-r--r-- | src/lib.rs | 2091 |
1 files changed, 2091 insertions, 0 deletions
diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..59b3940 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,2091 @@ +#![no_std] + +#![allow(non_snake_case)] + +#[cfg(feature="use-serde")] +#[macro_use] +extern crate serde_derive; + +use core::fmt; + +use yaxpeax_arch::{Arch, Decoder, LengthedInstruction}; + +#[allow(non_camel_case_types)] +#[derive(Debug, Copy, Clone)] +pub enum Opcode { + ABS, + ADC(Size), + ADCF(Size), + ADD(Size), + ADJNZ(Size), + AND(Size), + BAND, + BCLR, + BMEQ, + BMGEU, + BMGT, + BMGTU, + BMLE, + BMLEU, + BMLTU, + BMLT, + BMNO, + BMGE, + BMN, + BMNE, + BMO, + BMPZ, + BNAND, + BNOR, + BNOT, + BNTST, + BNXOR, + BOR, + BRK, + BSET, + BTST, + BTSTC, + BTSTS, + BXOR, + CMP(Size), + DADC, + DADD, + DEC(Size), + DIV(Size), + DIVU(Size), + DIVX(Size), + DSBB, + DSUB, + ENTER, + EXITD, + EXTS, + GE, + INC(Size), + INT, + INTO, + JEQ, + JGE, + JGEU, + JGT, + JGTU, + JLE, + JLEU, + JLT, + JLTU, + JMPI, + JMPS, + JMP(Size), + JN, + JNE, + JNO, + JO, + JPZ, + JSRI, + JSRS, + JSR_A, + JSR_W, + LDC, + LDCTX, + LDE, + LDIPL, + LT, + MOV(Size), + MOVA, + MOVHH, + MOVHL, + MOVLH, + MOVLL, + MUL, + MULU(Size), + NEG, + NO, + NOP, + NOT(Size), + OR(Size), + POP, + POPC, + POPM, + PUSH(Size), + PUSHA, + PUSHC, + PUSHM, + REIT, + RMPA(Size), + ROLC, + RORC, + ROT(Size), + RTS, + SBB(Size), + SHA(Size), + SHL(Size), + SMOVB(Size), + SMOVF(Size), + SSTR(Size), + STC, + STCTX, + STE, + STNZ, + STX, + STZ, + STZX, + SUB(Size), + TST(Size), + UND, + WAIT, + XCHG(Size), + XOR(Size), +} + +impl fmt::Display for Opcode { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + match self { + Opcode::ABS => write!(f, "abs"), + Opcode::ADC(size) => write!(f, "adc.{}", size), + Opcode::ADCF(size) => write!(f, "adcf.{}", size), + Opcode::ADD(size) => write!(f, "add.{}", size), + Opcode::ADJNZ(size) => write!(f, "adjnz.{}", size), + Opcode::AND(size) => write!(f, "and.{}", size), + Opcode::BAND => write!(f, "band"), + Opcode::BCLR => write!(f, "bclr"), + Opcode::BMEQ => write!(f, "bmeq"), + Opcode::BMGEU => write!(f, "bmgeu"), + Opcode::BMGT => write!(f, "bmgt"), + Opcode::BMGTU => write!(f, "bmgtu"), + Opcode::BMLE => write!(f, "bmle"), + Opcode::BMLEU => write!(f, "bmleu"), + Opcode::BMLTU => write!(f, "bmltu"), + Opcode::BMLT => write!(f, "bmlt"), + Opcode::BMNO => write!(f, "bmno"), + Opcode::BMGE => write!(f, "bmge"), + Opcode::BMN => write!(f, "bmn"), + Opcode::BMNE => write!(f, "bmne"), + Opcode::BMO => write!(f, "bmo"), + Opcode::BMPZ => write!(f, "bmpz"), + Opcode::BNAND => write!(f, "bnand"), + Opcode::BNOR => write!(f, "bnor"), + Opcode::BNOT => write!(f, "bnot"), + Opcode::BNTST => write!(f, "bntst"), + Opcode::BNXOR => write!(f, "bnxor"), + Opcode::BOR => write!(f, "bor"), + Opcode::BRK => write!(f, "brk"), + Opcode::BSET => write!(f, "bset"), + Opcode::BTST => write!(f, "btst"), + Opcode::BTSTC => write!(f, "btstc"), + Opcode::BTSTS => write!(f, "btsts"), + Opcode::BXOR => write!(f, "bxor"), + Opcode::CMP(size) => write!(f, "cmp.{}", size), + Opcode::DADC => write!(f, "dadc"), + Opcode::DADD => write!(f, "dadd"), + Opcode::DEC(size) => write!(f, "dec.{}", size), + Opcode::DIV(size) => write!(f, "div.{}", size), + Opcode::DIVU(size) => write!(f, "divu.{}", size), + Opcode::DIVX(size) => write!(f, "divx.{}", size), + Opcode::DSBB => write!(f, "dsbb"), + Opcode::DSUB => write!(f, "dsub"), + Opcode::ENTER => write!(f, "enter"), + Opcode::EXITD => write!(f, "exitd"), + Opcode::EXTS => write!(f, "exts"), + Opcode::GE => write!(f, "ge"), + Opcode::INC(size) => write!(f, "inc.{}", size), + Opcode::INT => write!(f, "int"), + Opcode::INTO => write!(f, "into"), + Opcode::JEQ => write!(f, "jeq"), + Opcode::JGE => write!(f, "jge"), + Opcode::JGEU => write!(f, "jgeu"), + Opcode::JGT => write!(f, "jgt"), + Opcode::JGTU => write!(f, "jgtu"), + Opcode::JLE => write!(f, "jle"), + Opcode::JLEU => write!(f, "jleu"), + Opcode::JLT => write!(f, "jlt"), + Opcode::JLTU => write!(f, "jltu"), + Opcode::JMPI => write!(f, "jmpi"), + Opcode::JMPS => write!(f, "jmps"), + Opcode::JMP(size) => write!(f, "jmp.{}", size), + Opcode::JN => write!(f, "jn"), + Opcode::JNE => write!(f, "jne"), + Opcode::JNO => write!(f, "jno"), + Opcode::JO => write!(f, "jo"), + Opcode::JPZ => write!(f, "jpz"), + Opcode::JSRI => write!(f, "jsri"), + Opcode::JSRS => write!(f, "jsrs"), + Opcode::JSR_A => write!(f, "jsr_a"), + Opcode::JSR_W => write!(f, "jsr_w"), + Opcode::LDC => write!(f, "ldc"), + Opcode::LDCTX => write!(f, "ldctx"), + Opcode::LDE => write!(f, "lde"), + Opcode::LDIPL => write!(f, "ldipl"), + Opcode::LT => write!(f, "lt"), + Opcode::MOV(size) => write!(f, "mov.{}", size), + Opcode::MOVA => write!(f, "mova"), + Opcode::MOVHH => write!(f, "movhh"), + Opcode::MOVHL => write!(f, "movhl"), + Opcode::MOVLH => write!(f, "movlh"), + Opcode::MOVLL => write!(f, "movll"), + Opcode::MUL => write!(f, "mul"), + Opcode::MULU(size) => write!(f, "mulu.{}", size), + Opcode::NEG => write!(f, "neg"), + Opcode::NO => write!(f, "no"), + Opcode::NOP => write!(f, "nop"), + Opcode::NOT(size) => write!(f, "not.{}", size), + Opcode::OR(size) => write!(f, "or.{}", size), + Opcode::POP => write!(f, "pop"), + Opcode::POPC => write!(f, "popc"), + Opcode::POPM => write!(f, "popm"), + Opcode::PUSH(size) => write!(f, "push.{}", size), + Opcode::PUSHA => write!(f, "pusha"), + Opcode::PUSHC => write!(f, "pushc"), + Opcode::PUSHM => write!(f, "pushm"), + Opcode::REIT => write!(f, "reit"), + Opcode::RMPA(size) => write!(f, "rmpa.{}", size), + Opcode::ROLC => write!(f, "rolc"), + Opcode::RORC => write!(f, "rorc"), + Opcode::ROT(size) => write!(f, "rot.{}", size), + Opcode::RTS => write!(f, "rts"), + Opcode::SBB(size) => write!(f, "sbb.{}", size), + Opcode::SHA(size) => write!(f, "sha.{}", size), + Opcode::SHL(size) => write!(f, "shl.{}", size), + Opcode::SMOVB(size) => write!(f, "smovb.{}", size), + Opcode::SMOVF(size) => write!(f, "smovf.{}", size), + Opcode::SSTR(size) => write!(f, "sstr.{}", size), + Opcode::STC => write!(f, "stc"), + Opcode::STCTX => write!(f, "stctx"), + Opcode::STE => write!(f, "ste"), + Opcode::STNZ => write!(f, "stnz"), + Opcode::STX => write!(f, "stx"), + Opcode::STZ => write!(f, "stz"), + Opcode::STZX => write!(f, "stzx"), + Opcode::SUB(size) => write!(f, "sub.{}", size), + Opcode::TST(size) => write!(f, "tst.{}", size), + Opcode::UND => write!(f, "und"), + Opcode::WAIT => write!(f, "wait"), + Opcode::XCHG(size) => write!(f, "xchg.{}", size), + Opcode::XOR(size) => write!(f, "xor.{}", size), + } + } +} + +#[derive(Debug, Copy, Clone)] +pub enum Register { + R0L, + R0H, + R1L, + R1H, + R0, + R1, + R2, + R3, + R2R0, + R3R1, + A0, + A1, + A1A0, + FB, + SB, + SP, + INTBL, + INTBH, + FLG, + ISP, +} + +impl fmt::Display for Register { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + use Register::*; + match self { + R0L => write!(f, "r0l"), + R0H => write!(f, "r0h"), + R1L => write!(f, "r1l"), + R1H => write!(f, "r1h"), + R0 => write!(f, "r0"), + R1 => write!(f, "r1"), + R2 => write!(f, "r2"), + R3 => write!(f, "r3"), + R2R0 => write!(f, "r2r0"), + R3R1 => write!(f, "r3r1"), + A0 => write!(f, "a0"), + A1 => write!(f, "a1"), + A1A0 => write!(f, "a1a0"), + FB => write!(f, "fb"), + SB => write!(f, "sb"), + SP => write!(f, "sp"), + INTBL => write!(f, "intbl"), + INTBH => write!(f, "intbh"), + FLG => write!(f, "flg"), + ISP => write!(f, "isp"), + } + } +} + +#[derive(Debug, Copy, Clone)] +pub enum Operand { + Register(Register), + RegisterBit(Register, u8), + ImmediateI16(i16), + ImmediateU16(u16), + RegDerefBit(Register, i16), + RegDeref(Register, i16), + AbsoluteBit(u16), + Absolute(u32), + Displacement(i16), + RegList(u8), +} + +impl fmt::Display for Operand { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + use Operand::*; + match self { + Register(reg) => write!(f, "{}", reg), + ImmediateI16(imm) => { + if *imm == core::i16::MIN { + write!(f, "#-8000h") + } else if *imm < 0 { + write!(f, "#-{:02x}h", -*imm) + } else { + write!(f, "#{:02x}h", *imm) + } + }, + ImmediateU16(imm) => write!(f, "#{:02x}h", imm), + RegDeref(reg, offset) => { + if *offset == core::i16::MIN { + write!(f, "#-8000h") + } else if *offset == 0 { + write!(f, "[{}]", reg) + } else if *offset < 0 { + write!(f, "-{}[{}]", -offset, reg) + } else { + write!(f, "{}[{}]", offset, reg) + } + } + Displacement(offset) => { + if *offset == core::i16::MIN { + write!(f, "$-32768") + } else if *offset < 0 { + write!(f, "$-{}", -*offset) + } else { + write!(f, "$+{}", *offset) + } + } + _ => Ok(()) + } + } +} + +#[allow(non_camel_case_types)] +#[derive(Debug, Copy, Clone, PartialEq)] +enum OperandSpec { + Nothing, + Zero, + Imm4, + Imm8, + Imm82, // Imm8, part t2. used in STZX. + Imm16, + Label8, + Bit0, + Bit1, + Bit2, + Bit3, + Bit4, + Bit5, + Bit6, + Bit7, + R0L, + R0H, + R1L, + R1H, + R0, + R1, + R2, + R3, + R2R0, + R3R1, + A0, + A1, + A1A0, + Bit_R0, + Bit_R1, + Bit_R2, + Bit_R3, + Bit_A0, + Bit_A1, + Bit_Deref_A0, + Bit_Deref_A1, + Bit_Disp8_A0, + Bit_Disp8_A1, + Bit_Disp8_SB, + Bit_Disp8_FB, + Bit_Disp16_A0, + Bit_Disp16_A1, + Bit_Disp16_SB, + Bit_Abs16, + Disp8_A0, + Disp8_A1, + Disp8_SB, + Disp8_FB, + Disp8_SP, + Disp16_A0, + Disp16_A1, + Disp16_SB, + Disp20_A0, + Disp20_A1, + Deref_A0, + Deref_A1, + Deref_A1A0, + Abs16, + Disp2_8_A0, + Disp2_8_A1, + Disp2_8_SB, + Disp2_8_FB, + Disp2_16_A0, + Disp2_16_A1, + Disp2_16_SB, + Abs2_16, + Abs20, + Disp8, + Disp16, + RegList, + INTBL, + INTBH, + FLG, + ISP, + SP, + SB, + FB, +} + +#[derive(Debug, Copy, Clone, PartialEq)] +pub enum Size { + B, // 0 in almost(?) all places a size bit is present + W, // 1 in almost(?) all places a size bit is present + L, // for sha.l/shl.l + S, // for jmp.s, three bits. + A, // for jmp.a, twenty bit absolute. +} + +impl fmt::Display for Size { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + match self { + Size::B => write!(f, "b"), + Size::W => write!(f, "w"), + Size::L => write!(f, "l"), + Size::S => write!(f, "s"), + Size::A => write!(f, "a"), + } + } +} + +impl Size { + fn as_bytes(&self) -> u8 { + match self { + Size::B => 1, + Size::W => 2, + Size::L => { panic!("should not have to get number of bytes for L"); }, + Size::S => { panic!("should not have to get number of bytes for S"); }, + Size::A => { panic!("should not have to get number of bytes for A"); }, + } + } +} + +#[derive(Debug, Copy, Clone)] +pub struct Instruction { + pub opcode: Opcode, + operands: [OperandSpec; 3], + // we need both `dispabs` and `imm_wide` to handle the widest instructions we can see: + // LDE or STE with 20-bit displacement and 16-bit displacement. + // either an Imm16, an Imm8, or Imm82:Imm8. mutually exclusive with 20-bit disp/abs, so put those here too. + // + // Imm4 will sometimes cohabitate with two displacements (ADJNZ with displacement dest and + // label), so cram the label byte into here as well. accessed as `OperandSpec::Label8`. + imm_wide: u32, + dispabs: u16, // 8 or 16-bit displacement or absolute address + length: u8, +} + +impl Instruction { + pub fn operand(&self, idx: u8) -> Option<Operand> { + use OperandSpec::*; + let operand = match self.operands[idx as usize] { + Nothing => { return None; }, + Zero => Operand::ImmediateU16(0), + Imm4 => Operand::ImmediateI16(self.imm_wide as u8 as i8 as i16), + Imm8 => Operand::ImmediateI16(self.imm_wide as u8 as i8 as i16), + Imm16 => Operand::ImmediateI16(self.imm_wide as i16), + // Imm8 part 2 is used in STZX, and is the second byte of imm_wide + Imm82 | + // and Label8 is used in ADJNZ, also stored in the second byte of inn_wide + Label8 => Operand::ImmediateI16((self.imm_wide as i16) >> 8), + Bit0 => Operand::ImmediateU16(0), + Bit1 => Operand::ImmediateU16(1), + Bit2 => Operand::ImmediateU16(2), + Bit3 => Operand::ImmediateU16(3), + Bit4 => Operand::ImmediateU16(4), + Bit5 => Operand::ImmediateU16(5), + Bit6 => Operand::ImmediateU16(6), + Bit7 => Operand::ImmediateU16(7), + R0L => Operand::Register(Register::R0L), + R0H => Operand::Register(Register::R0H), + R1L => Operand::Register(Register::R1L), + R1H => Operand::Register(Register::R1H), + R0 => Operand::Register(Register::R0), + R1 => Operand::Register(Register::R1), + R2 => Operand::Register(Register::R2), + R3 => Operand::Register(Register::R3), + R2R0 => Operand::Register(Register::R2R0), + R3R1 => Operand::Register(Register::R3R1), + A0 => Operand::Register(Register::A0), + A1 => Operand::Register(Register::A1), + A1A0 => Operand::Register(Register::A1A0), + Bit_R0 => Operand::RegisterBit(Register::R0, self.dispabs as u8), + Bit_R1 => Operand::RegisterBit(Register::R1, self.dispabs as u8), + Bit_R2 => Operand::RegisterBit(Register::R2, self.dispabs as u8), + Bit_R3 => Operand::RegisterBit(Register::R3, self.dispabs as u8), + Bit_A0 => Operand::RegisterBit(Register::A0, self.dispabs as u8), + Bit_A1 => Operand::RegisterBit(Register::A1, self.dispabs as u8), + Bit_Deref_A0 => Operand::RegDerefBit(Register::A0, 0), + Bit_Deref_A1 => Operand::RegDerefBit(Register::A1, 0), + Bit_Disp8_A0 => Operand::RegDerefBit(Register::A0, self.dispabs as i16), + Bit_Disp8_A1 => Operand::RegDerefBit(Register::A1, self.dispabs as i16), + Bit_Disp8_SB => Operand::RegDerefBit(Register::SB, self.dispabs as i16), + Bit_Disp8_FB => Operand::RegDerefBit(Register::FB, self.dispabs as i16), + Bit_Disp16_A0 => Operand::RegDerefBit(Register::A0, self.dispabs as i16), + Bit_Disp16_A1 => Operand::RegDerefBit(Register::A1, self.dispabs as i16), + Bit_Disp16_SB => Operand::RegDerefBit(Register::SB, self.dispabs as i16), + Bit_Abs16 => Operand::AbsoluteBit(self.dispabs), + Disp8_A0 => Operand::RegDeref(Register::A0, self.dispabs as i8 as i16), + Disp8_A1 => Operand::RegDeref(Register::A1, self.dispabs as i8 as i16), + Disp8_SB => Operand::RegDeref(Register::SB, self.dispabs as i8 as i16), + Disp8_FB => Operand::RegDeref(Register::FB, self.dispabs as i8 as i16), + Disp8_SP => Operand::RegDeref(Register::SP, self.dispabs as i8 as i16), + Disp16_A0 => Operand::RegDeref(Register::A0, self.dispabs as i16), + Disp16_A1 => Operand::RegDeref(Register::A1, self.dispabs as i16), + Disp16_SB => Operand::RegDeref(Register::SB, self.dispabs as i16), + Disp20_A0 => Operand::RegDeref(Register::A0, self.imm_wide as i16), + Disp20_A1 => Operand::RegDeref(Register::A1, self.imm_wide as i16), + Deref_A0 => Operand::RegDeref(Register::A0, self.dispabs as i16), + Deref_A1 => Operand::RegDeref(Register::A1, self.dispabs as i16), + Deref_A1A0 => Operand::RegDeref(Register::A1A0, self.dispabs as i16), + Abs16 => Operand::Absolute(self.dispabs as u32), + Disp2_8_A0 => Operand::RegDeref(Register::A0, self.imm_wide as i8 as i16), + Disp2_8_A1 => Operand::RegDeref(Register::A1, self.imm_wide as i8 as i16), + Disp2_8_SB => Operand::RegDeref(Register::SB, self.imm_wide as i8 as i16), + Disp2_8_FB => Operand::RegDeref(Register::FB, self.imm_wide as i8 as i16), + Disp2_16_A0 => Operand::RegDeref(Register::A0, self.imm_wide as i16), + Disp2_16_A1 => Operand::RegDeref(Register::A1, self.imm_wide as i16), + Disp2_16_SB => Operand::RegDeref(Register::SB, self.imm_wide as i16), + Abs2_16 => Operand::Absolute(self.imm_wide), + Abs20 => Operand::Absolute(self.imm_wide), + Disp8 => Operand::Displacement(self.dispabs as u8 as i8 as i16), + Disp16 => Operand::Displacement(self.dispabs as i16), + RegList => Operand::RegList(self.imm_wide as u8), + INTBL => Operand::Register(Register::INTBL), + INTBH => Operand::Register(Register::INTBH), + FLG => Operand::Register(Register::FLG), + ISP => Operand::Register(Register::ISP), + SP => Operand::Register(Register::SP), + SB => Operand::Register(Register::SB), + FB => Operand::Register(Register::FB), + }; + Some(operand) + } +} + +#[cfg(feature="use-serde")] +#[derive(Debug, Serialize, Deserialize)] +pub struct M16C; + +#[cfg(not(feature="use-serde"))] +#[derive(Debug)] +pub struct M16C; + +impl Arch for M16C { + type Address = u32; + type Instruction = Instruction; + type DecodeError = DecodeError; + type Decoder = InstDecoder; + type Operand = Operand; +} + +impl fmt::Display for Instruction { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "{}", self.opcode)?; + match self.operand(0) { + None => return Ok(()), + Some(op) => { write!(f, " {}", op)?; } + } + match self.operand(1) { + None => return Ok(()), + Some(op) => { write!(f, ", {}", op)?; } + } + Ok(()) + } +} + +impl LengthedInstruction for Instruction { + type Unit = <M16C as Arch>::Address; + + fn min_size() -> Self::Unit { + 1 + } + fn len(&self) -> Self::Unit { + self.length as u32 + } +} + +impl Default for Instruction { + fn default() -> Self { + Instruction { + opcode: Opcode::NOP, + operands: [OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing], + imm_wide: 0, + dispabs: 0, + length: 0 + } + } +} + +#[derive(Debug, PartialEq)] +pub enum DecodeError { + ExhaustedInput, + InvalidOpcode, + InvalidOperand, +} + +impl fmt::Display for DecodeError { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + match self { + DecodeError::ExhaustedInput => write!(f, "exhausted input"), + DecodeError::InvalidOpcode => write!(f, "invalid opcode"), + DecodeError::InvalidOperand => write!(f, "invalid operand"), + } + } +} + +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 } +} + +impl yaxpeax_arch::Instruction for Instruction { + // currently only accept instructions that are well-defined. + fn well_defined(&self) -> bool { true } +} + +#[derive(Default, Debug)] +pub struct InstDecoder {} + +impl fmt::Display for InstDecoder { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + write!(f, "m16c") + } +} + +impl Decoder<Instruction> for InstDecoder { + type Error = DecodeError; + + fn decode_into<T: IntoIterator<Item=u8>>(&self, inst: &mut Instruction, bytes: T) -> Result<(), DecodeError> { + let mut bytes_iter = bytes.into_iter(); + decode(self, inst, &mut bytes_iter) + } +} + +enum OperandCategory { + ADJNZ, + Op74, + Op76, + Op78, + Op7A, + Op7B, + Op7C, + Op7D, + Op7E, + OpEB, + SrcDestRegOrDeref, + Imm4Dest, + DispOpcodeLow3, +} + +enum OperandInterpretation { + Just([OperandSpec; 3]), + Reinterpret(OperandCategory) +} + +fn decode<T: Iterator<Item=u8>>(_decoder: &InstDecoder, inst: &mut Instruction, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + // IF there is a size bit, it is the low bit of the first byte. + let size = if byte & 1 == 0 { + Size::B + } else { + Size::W + }; + use OperandInterpretation::*; + let (opcode, interpretation) = match byte { + 0b0000_0000 => (Opcode::BRK, Just([OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0000_0001 => (Opcode::MOV(Size::B), Just([OperandSpec::R0L, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0000_0010 => (Opcode::MOV(Size::B), Just([OperandSpec::R0L, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b0000_0011 => (Opcode::MOV(Size::B), Just([OperandSpec::R0L, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b0000_0100 => (Opcode::NOP, Just([OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0000_0101 => (Opcode::MOV(Size::B), Just([OperandSpec::R0H, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0000_0110 => (Opcode::MOV(Size::B), Just([OperandSpec::R0H, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b0000_0111 => (Opcode::MOV(Size::B), Just([OperandSpec::R0H, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b0000_1000 | + 0b0000_1001 | + 0b0000_1010 | + 0b0000_1011 | + 0b0000_1100 | + 0b0000_1101 | + 0b0000_1110 | + 0b0000_1111 => { + return Err(DecodeError::InvalidOperand); + }, + 0b0001_0000 => (Opcode::AND(Size::B), Just([OperandSpec::R0H, OperandSpec::R0L, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0001_0001 => (Opcode::AND(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0001_0010 => (Opcode::AND(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0001_0011 => (Opcode::AND(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0001_0100 => (Opcode::AND(Size::B), Just([OperandSpec::R0L, OperandSpec::R0H, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0001_0101 => (Opcode::AND(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0001_0110 => (Opcode::AND(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0001_0111 => (Opcode::AND(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0001_1000 => (Opcode::OR(Size::B), Just([OperandSpec::R0H, OperandSpec::R0L, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0001_1001 => (Opcode::OR(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0001_1010 => (Opcode::OR(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0001_1011 => (Opcode::OR(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0001_1100 => (Opcode::OR(Size::B), Just([OperandSpec::R0L, OperandSpec::R0H, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0001_1101 => (Opcode::OR(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0001_1110 => (Opcode::OR(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0001_1111 => (Opcode::OR(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0010_0000 => (Opcode::ADD(Size::B), Just([OperandSpec::R0H, OperandSpec::R0L, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0010_0001 => (Opcode::ADD(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0010_0010 => (Opcode::ADD(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0010_0011 => (Opcode::ADD(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0010_0100 => (Opcode::ADD(Size::B), Just([OperandSpec::R0L, OperandSpec::R0H, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0010_0101 => (Opcode::ADD(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0010_0110 => (Opcode::ADD(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0010_0111 => (Opcode::ADD(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0010_1000 => (Opcode::SUB(Size::B), Just([OperandSpec::R0H, OperandSpec::R0L, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0010_1001 => (Opcode::SUB(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0010_1010 => (Opcode::SUB(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0010_1011 => (Opcode::SUB(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0010_1100 => (Opcode::SUB(Size::B), Just([OperandSpec::R0L, OperandSpec::R0H, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0010_1101 => (Opcode::SUB(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0010_1110 => (Opcode::SUB(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0010_1111 => (Opcode::SUB(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0011_0000 => (Opcode::MOV(Size::B), Just([OperandSpec::R0H, OperandSpec::A0, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0011_0001 => (Opcode::MOV(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::A0, OperandSpec::Nothing])), + 0b0011_0010 => (Opcode::MOV(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::A0, OperandSpec::Nothing])), + 0b0011_0011 => (Opcode::MOV(Size::B), Just([OperandSpec::Abs16, OperandSpec::A0, OperandSpec::Nothing])), + 0b0011_0100 => (Opcode::MOV(Size::B), Just([OperandSpec::R0L, OperandSpec::A1, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0011_0101 => (Opcode::MOV(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::A1, OperandSpec::Nothing])), + 0b0011_0110 => (Opcode::MOV(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::A1, OperandSpec::Nothing])), + 0b0011_0111 => (Opcode::MOV(Size::B), Just([OperandSpec::Abs16, OperandSpec::A1, OperandSpec::Nothing])), + 0b0011_1000 => (Opcode::CMP(Size::B), Just([OperandSpec::R0H, OperandSpec::R0L, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0011_1001 => (Opcode::CMP(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0011_1010 => (Opcode::CMP(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0011_1011 => (Opcode::CMP(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0L, OperandSpec::Nothing])), + 0b0011_1100 => (Opcode::CMP(Size::B), Just([OperandSpec::R0L, OperandSpec::R0H, OperandSpec::Nothing])), // src is written R0L/R0H, what picks the register? + 0b0011_1101 => (Opcode::CMP(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0011_1110 => (Opcode::CMP(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0011_1111 => (Opcode::CMP(Size::B), Just([OperandSpec::Abs16, OperandSpec::R0H, OperandSpec::Nothing])), + 0b0100_0000 => (Opcode::BCLR, Just([OperandSpec::Bit0, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0001 => (Opcode::BCLR, Just([OperandSpec::Bit1, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0010 => (Opcode::BCLR, Just([OperandSpec::Bit2, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0011 => (Opcode::BCLR, Just([OperandSpec::Bit3, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0100 => (Opcode::BCLR, Just([OperandSpec::Bit4, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0101 => (Opcode::BCLR, Just([OperandSpec::Bit5, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0110 => (Opcode::BCLR, Just([OperandSpec::Bit6, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_0111 => (Opcode::BCLR, Just([OperandSpec::Bit7, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1000 => (Opcode::BSET, Just([OperandSpec::Bit0, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1001 => (Opcode::BSET, Just([OperandSpec::Bit1, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1010 => (Opcode::BSET, Just([OperandSpec::Bit2, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1011 => (Opcode::BSET, Just([OperandSpec::Bit3, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1100 => (Opcode::BSET, Just([OperandSpec::Bit4, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1101 => (Opcode::BSET, Just([OperandSpec::Bit5, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1110 => (Opcode::BSET, Just([OperandSpec::Bit6, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0100_1111 => (Opcode::BSET, Just([OperandSpec::Bit7, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0000 => (Opcode::BNOT, Just([OperandSpec::Bit0, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0001 => (Opcode::BNOT, Just([OperandSpec::Bit1, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0010 => (Opcode::BNOT, Just([OperandSpec::Bit2, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0011 => (Opcode::BNOT, Just([OperandSpec::Bit3, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0100 => (Opcode::BNOT, Just([OperandSpec::Bit4, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0101 => (Opcode::BNOT, Just([OperandSpec::Bit5, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0110 => (Opcode::BNOT, Just([OperandSpec::Bit6, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_0111 => (Opcode::BNOT, Just([OperandSpec::Bit7, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1000 => (Opcode::BTST, Just([OperandSpec::Bit0, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1001 => (Opcode::BTST, Just([OperandSpec::Bit1, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1010 => (Opcode::BTST, Just([OperandSpec::Bit2, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1011 => (Opcode::BTST, Just([OperandSpec::Bit3, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1100 => (Opcode::BTST, Just([OperandSpec::Bit4, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1101 => (Opcode::BTST, Just([OperandSpec::Bit5, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1110 => (Opcode::BTST, Just([OperandSpec::Bit6, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0101_1111 => (Opcode::BTST, Just([OperandSpec::Bit7, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b0110_0000 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0001 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0010 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0011 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0100 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0101 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0110 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_0111 => (Opcode::JMP(Size::S), Reinterpret(OperandCategory::DispOpcodeLow3)), + 0b0110_1000 => (Opcode::JGEU, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1001 => (Opcode::JGTU, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1010 => (Opcode::JEQ, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1011 => (Opcode::JN, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1100 => (Opcode::JLTU, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1101 => (Opcode::JLEU, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1110 => (Opcode::JNE, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0110_1111 => (Opcode::JPZ, Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b0111_0000 => (Opcode::MULU(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b0111_0001 => (Opcode::MULU(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b0111_0010 => (Opcode::MOV(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b0111_0011 => (Opcode::MOV(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b0111_0100 => (Opcode::NOP, Reinterpret(OperandCategory::Op74)), + 0b0111_0101 => (Opcode::NOP, Reinterpret(OperandCategory::Op74)), + 0b0111_0110 => (Opcode::NOP, Reinterpret(OperandCategory::Op76)), + 0b0111_0111 => (Opcode::NOP, Reinterpret(OperandCategory::Op76)), + 0b0111_1000 => (Opcode::NOP, Reinterpret(OperandCategory::Op78)), + 0b0111_1001 => (Opcode::NOP, Reinterpret(OperandCategory::Op78)), + 0b0111_1010 => (Opcode::NOP, Reinterpret(OperandCategory::Op7A)), + 0b0111_1011 => (Opcode::NOP, Reinterpret(OperandCategory::Op7B)), + 0b0111_1100 => (Opcode::NOP, Reinterpret(OperandCategory::Op7C)), + 0b0111_1101 => (Opcode::NOP, Reinterpret(OperandCategory::Op7D)), + 0b0111_1110 => (Opcode::NOP, Reinterpret(OperandCategory::Op7E)), + 0b0111_1111 => { return Err(DecodeError::InvalidOperand); }, + 0b1000_0000 => (Opcode::TST(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1000_0001 => (Opcode::TST(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1000_0010 => (Opcode::PUSH(Size::B), Just([OperandSpec::R0L, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1000_0011 => (Opcode::ADD(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1000_0100 => (Opcode::ADD(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1000_0101 => (Opcode::ADD(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1000_0110 => (Opcode::ADD(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1000_0111 => (Opcode::ADD(Size::B), Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1000_1000 => (Opcode::XOR(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1000_1001 => (Opcode::XOR(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1000_1010 => (Opcode::PUSH(Size::B), Just([OperandSpec::R0H, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1000_1011 => (Opcode::SUB(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1000_1100 => (Opcode::SUB(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1000_1101 => (Opcode::SUB(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1000_1110 => (Opcode::SUB(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1000_1111 => (Opcode::SUB(Size::B), Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1001_0000 => (Opcode::AND(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1001_0001 => (Opcode::AND(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1001_0010 => (Opcode::POP, Just([OperandSpec::R0L, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1001_0011 => (Opcode::AND(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1001_0100 => (Opcode::AND(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1001_0101 => (Opcode::AND(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1001_0110 => (Opcode::AND(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1001_0111 => (Opcode::AND(Size::B), Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1001_1000 => (Opcode::OR(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1001_1001 => (Opcode::OR(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1001_1010 => (Opcode::POP, Just([OperandSpec::R0H, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1001_1011 => (Opcode::OR(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1001_1100 => (Opcode::OR(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1001_1101 => (Opcode::OR(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1001_1110 => (Opcode::OR(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1001_1111 => (Opcode::OR(Size::B), Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1010_0000 => (Opcode::ADD(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1010_0001 => (Opcode::ADD(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1010_0010 => (Opcode::MOV(Size::W), Just([OperandSpec::Imm16, OperandSpec::A0, OperandSpec::Nothing])), + 0b1010_0011 => (Opcode::INC(Size::B), Just([OperandSpec::R0H, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_0100 => (Opcode::INC(Size::B), Just([OperandSpec::R0L, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_0101 => (Opcode::INC(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_0110 => (Opcode::INC(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_0111 => (Opcode::INC(Size::B), Just([OperandSpec::Abs16, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_1000 => (Opcode::SUB(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1010_1001 => (Opcode::SUB(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1010_1010 => (Opcode::MOV(Size::W), Just([OperandSpec::Imm16, OperandSpec::A1, OperandSpec::Nothing])), + 0b1010_1011 => (Opcode::DEC(Size::B), Just([OperandSpec::R0H, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_1100 => (Opcode::DEC(Size::B), Just([OperandSpec::R0L, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_1101 => (Opcode::DEC(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_1110 => (Opcode::DEC(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1010_1111 => (Opcode::DEC(Size::B), Just([OperandSpec::Abs16, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_0000 => (Opcode::ADC(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1011_0001 => (Opcode::ADC(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1011_0010 => (Opcode::INC(Size::W), Just([OperandSpec::A0, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_0011 => (Opcode::MOV(Size::B), Just([OperandSpec::Zero, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1011_0100 => (Opcode::MOV(Size::B), Just([OperandSpec::Zero, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1011_0101 => (Opcode::MOV(Size::B), Just([OperandSpec::Zero, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1011_0110 => (Opcode::MOV(Size::B), Just([OperandSpec::Zero, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1011_0111 => (Opcode::MOV(Size::B), Just([OperandSpec::Zero, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1011_1000 => (Opcode::SBB(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1011_1001 => (Opcode::SBB(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1011_1010 => (Opcode::INC(Size::W), Just([OperandSpec::A1, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_1011 => (Opcode::NOT(Size::B), Just([OperandSpec::R0H, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_1100 => (Opcode::NOT(Size::B), Just([OperandSpec::R0L, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_1101 => (Opcode::NOT(Size::B), Just([OperandSpec::Disp8_SB, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_1110 => (Opcode::NOT(Size::B), Just([OperandSpec::Disp8_FB, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1011_1111 => (Opcode::NOT(Size::B), Just([OperandSpec::Abs16, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1100_0000 => (Opcode::CMP(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1100_0001 => (Opcode::CMP(size), Reinterpret(OperandCategory::SrcDestRegOrDeref)), + 0b1100_0010 => (Opcode::PUSH(Size::W), Just([OperandSpec::A0, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1100_0011 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1100_0100 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1100_0101 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1100_0110 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1100_0111 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1100_1000 => (Opcode::ADD(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1100_1001 => (Opcode::ADD(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1100_1010 => (Opcode::PUSH(Size::W), Just([OperandSpec::A1, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1100_1011 => (Opcode::STZ, Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1100_1100 => (Opcode::STZ, Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1100_1101 => (Opcode::STZ, Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1100_1110 => (Opcode::STX, Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1100_1111 => (Opcode::STZ, Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1101_0000 => (Opcode::CMP(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1101_0001 => (Opcode::CMP(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1101_0010 => (Opcode::POP, Just([OperandSpec::A0, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1101_0011 => (Opcode::STNZ, Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1101_0100 => (Opcode::STNZ, Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1101_0101 => (Opcode::STNZ, Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1101_0110 => (Opcode::STNZ, Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1101_0111 => (Opcode::STNZ, Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1101_1000 => (Opcode::MOV(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1101_1001 => (Opcode::MOV(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1101_1010 => (Opcode::POP, Just([OperandSpec::A1, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1101_1011 => (Opcode::STZX, Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Imm82])), + 0b1101_1100 => (Opcode::STZX, Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Imm82])), + 0b1101_1101 => (Opcode::STZX, Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Imm82])), + 0b1101_1110 => (Opcode::STZX, Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Imm82])), + 0b1101_1111 => (Opcode::STZX, Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Imm82])), + 0b1110_0000 => (Opcode::ROT(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1110_0001 => (Opcode::ROT(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1110_0010 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::A0, OperandSpec::Nothing])), + 0b1110_0011 => (Opcode::CMP(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0H, OperandSpec::Nothing])), + 0b1110_0100 => (Opcode::CMP(Size::B), Just([OperandSpec::Imm8, OperandSpec::R0L, OperandSpec::Nothing])), + 0b1110_0101 => (Opcode::CMP(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_SB, OperandSpec::Nothing])), + 0b1110_0110 => (Opcode::CMP(Size::B), Just([OperandSpec::Imm8, OperandSpec::Disp8_FB, OperandSpec::Nothing])), + 0b1110_0111 => (Opcode::CMP(Size::B), Just([OperandSpec::Imm8, OperandSpec::Abs16, OperandSpec::Nothing])), + 0b1110_1000 => (Opcode::SHA(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1110_1001 => (Opcode::SHA(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1110_1010 => (Opcode::MOV(Size::B), Just([OperandSpec::Imm8, OperandSpec::A1, OperandSpec::Nothing])), + 0b1110_1011 => (Opcode::NOP, Reinterpret(OperandCategory::OpEB)), // Opcode will be discarded + 0b1110_1100 => (Opcode::PUSHM, Just([OperandSpec::RegList, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1110_1101 => (Opcode::POPM, Just([OperandSpec::RegList, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1110_1110 => (Opcode::JMPS, Just([OperandSpec::Imm8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1110_1111 => (Opcode::JSRS, Just([OperandSpec::Imm8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_0000 => (Opcode::SHA(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1111_0001 => (Opcode::SHA(size), Reinterpret(OperandCategory::Imm4Dest)), + 0b1111_0010 => (Opcode::DEC(Size::W), Just([OperandSpec::A0, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_0011 => (Opcode::RTS, Just([OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_0100 => (Opcode::JMP(Size::W), Just([OperandSpec::Disp16, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_0101 => (Opcode::JSR_W, Just([OperandSpec::Disp16, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_0110 => (Opcode::INTO, Just([OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_0111 => { return Err(DecodeError::InvalidOperand); }, + 0b1111_1000 => (Opcode::ADJNZ(size), Reinterpret(OperandCategory::ADJNZ)), + 0b1111_1001 => (Opcode::ADJNZ(size), Reinterpret(OperandCategory::ADJNZ)), + 0b1111_1010 => (Opcode::DEC(Size::W), Just([OperandSpec::A1, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_1011 => (Opcode::REIT, Just([OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_1100 => (Opcode::JMP(Size::A), Just([OperandSpec::Abs20, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_1101 => (Opcode::JSR_A, Just([OperandSpec::Abs20, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_1110 => (Opcode::JMP(Size::B), Just([OperandSpec::Disp8, OperandSpec::Nothing, OperandSpec::Nothing])), + 0b1111_1111 => (Opcode::UND, Just([OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing])), + }; + inst.opcode = opcode; + match interpretation { + Just(operands) => { + inst.operands = operands; + + // in the base opcode map, if an immediate is specified it comes before bytes for + // displacement/absolute address that may be part of a destination. + // + // additionally, Imm8 or Imm16 is the first operand, if present. so look for that + // first. + if let OperandSpec::Imm8 = inst.operands[0] { + inst.imm_wide = read_imm(bytes, 1)? as u32; + inst.length += 1; + } + + // now, read bytes for remaining operands, EXCEPT STZX which we read most but not all + // of. it specifies a second imm8 after optional disp/abs + for op in inst.operands.iter() { + use OperandSpec::*; + match op { + RegList => { + inst.imm_wide = read_imm(bytes, 1)? as u32; + inst.length += 1; + }, + Disp8 | + Disp8_FB | + Disp8_SB => { + // have to sign extend in case these displacements are negative + inst.dispabs = read_imm(bytes, 1)? as i8 as i16 as u16; + inst.length += 1; + } + Disp16 | + Abs16 => { + inst.dispabs = read_imm(bytes, 2)? as u16; + inst.length += 2; + } + Abs20 => { + inst.dispabs = read_imm(bytes, 3)? as u16; + inst.length += 3; + } + Disp8_A0 | + Disp8_A1 | + Disp8_SP | + Disp16_A0 | + Disp16_A1 | + Disp16_SB | + Disp20_A0 | + Disp20_A1 | + Deref_A0 | + Deref_A1 | + Deref_A1A0 | + Disp2_8_A0 | + Disp2_8_A1 | + Disp2_8_SB | + Disp2_8_FB | + Disp2_16_A0 | + Disp2_16_A1 | + Disp2_16_SB | + Abs2_16 | + Bit_Disp8_A0 | + Bit_Disp8_A1 | + Bit_Disp8_SB | + Bit_Disp8_FB | + Bit_Disp16_A0 | + Bit_Disp16_A1 | + Bit_Disp16_SB | + Bit_Abs16 => { + panic!("unexpected operand spec for Just set of operands: {:?}", op); + } + // and other operands? yeah just ignore em + _ => {} + } + } + + // now for STZX, really,... + if let OperandSpec::Imm82 = inst.operands[2] { + inst.imm_wide |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u32) << 8; + inst.length += 1; + } + + return Ok(()); + }, + Reinterpret(OperandCategory::Op74) => { + return decode_op74(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op76) => { + return decode_op76(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op78) => { + return decode_op78(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op7A) => { + return decode_op7A(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op7B) => { + return decode_op7B(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op7C) => { + return decode_op7C(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op7D) => { + return decode_op7D(inst, size, bytes); + }, + Reinterpret(OperandCategory::Op7E) => { + return decode_op7E(inst, size, bytes); + }, + Reinterpret(OperandCategory::OpEB) => { + return decode_opEB(inst, size, bytes); + }, + Reinterpret(OperandCategory::Imm4Dest) => { + let operands = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + inst.imm_wide = (operands as i8 >> 4) as i32 as u32; + inst.operands[0] = OperandSpec::Imm4; + inst.operands[1] = Operand_RegDerefDispAbs(operands & 0b1111, size, inst, bytes)?; + inst.operands[2] = OperandSpec::Nothing; + } + Reinterpret(OperandCategory::DispOpcodeLow3) => { + inst.dispabs = (byte & 0b111) as u16; + inst.operands[0] = OperandSpec::Disp8; + inst.operands[1] = OperandSpec::Nothing; + inst.operands[2] = OperandSpec::Nothing; + } + Reinterpret(OperandCategory::ADJNZ) => { + // ADJNZ has operands like any other [IMM4|DEST] operand, but takes an additional byte + // for the destination label. + let operands = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + inst.imm_wide = ((operands as i8) >> 4) as u32; + inst.operands[0] = OperandSpec::Imm4; + inst.operands[1] = Operand_RegDerefDispAbs(operands & 0b1111, size, inst, bytes)?; + inst.operands[2] = OperandSpec::Label8; + } + Reinterpret(OperandCategory::SrcDestRegOrDeref) => { + // these instructions can read two disp8/disp16, so the first one can be handled + // normally, but the second will need some fixing up... + let operands = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + inst.operands[0] = Operand_RegDerefDispAbs(operands >> 4, size, inst, bytes)?; + inst.operands[1] = Operand_second_RegDerefDispAbs(operands & 0b1111, size, inst, bytes)?; + inst.operands[2] = OperandSpec::Nothing; + } + } + Ok(()) +} + +fn decode_op74<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + match byte >> 4 { + 0b0000 => { + inst.opcode = Opcode::STE; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Abs20; + inst.imm_wide = read_imm(bytes, 3)? & 0x0f_ff_ff; + inst.length += 3; + } + 0b0001 => { + inst.opcode = Opcode::STE; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Disp20_A0; + inst.imm_wide = read_imm(bytes, 3)? & 0x0f_ff_ff; + inst.length += 3; + } + 0b0010 => { + inst.opcode = Opcode::STE; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Deref_A1A0; + } + 0b0011 => { + inst.opcode = Opcode::MOV(size); + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Disp8_SP; + } + 0b0100 => { + inst.opcode = Opcode::PUSH(size); + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0101 => { + inst.opcode = Opcode::NEG; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0110 => { + inst.opcode = Opcode::ROT(size); + if size == Size::W && byte & 0b1111 == 0b0001 { + // invalid dest, would be R1 + return Err(DecodeError::InvalidOperand); + } else if size == Size::B && byte & 0b1111 == 0b0011 { + // invalid dest, would be R1H + return Err(DecodeError::InvalidOperand); + } + + inst.operands[0] = OperandSpec::R1H; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + 0b0111 => { + inst.opcode = Opcode::NOT(size); + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1000 => { + inst.opcode = Opcode::LDE; + inst.operands[0] = OperandSpec::Abs20; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + // careful! abs20 comes after dest disp/abs + inst.imm_wide = read_imm(bytes, 3)? & 0x0f_ff_ff; + inst.length += 3; + } + 0b1001 => { + inst.opcode = Opcode::LDE; + inst.operands[0] = OperandSpec::Disp20_A0; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + // careful! disp20 comes after dest disp/abs + inst.imm_wide = read_imm(bytes, 3)? & 0x0f_ff_ff; + inst.length += 3; + } + 0b1010 => { + inst.opcode = Opcode::LDE; + inst.operands[0] = OperandSpec::Deref_A1A0; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + 0b1011 => { + inst.opcode = Opcode::MOV(size); + inst.operands[0] = OperandSpec::Disp8_SP; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + // careful! disp8 comes after dest disp/abs + inst.dispabs = read_imm(bytes, 1)? as u16; + inst.length += 1; + } + 0b1100 => { + inst.opcode = Opcode::MOV(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + // careful! imm comes after dest disp/abs + inst.imm_wide = read_imm(bytes, size.as_bytes())? as u32; + inst.length += size.as_bytes(); + } + 0b1101 => { + inst.opcode = Opcode::POP; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1110 => { + inst.opcode = Opcode::SHL(size); + if size == Size::W && byte & 0b1111 == 0b0001 { + // invalid dest, would be R1 + return Err(DecodeError::InvalidOperand); + } else if size == Size::B && byte & 0b1111 == 0b0011 { + // invalid dest, would be R1H + return Err(DecodeError::InvalidOperand); + } + + inst.operands[0] = OperandSpec::R1H; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + 0b1111 => { + inst.opcode = Opcode::SHA(size); + if size == Size::W && byte & 0b1111 == 0b0001 { + // invalid dest, would be R1 + return Err(DecodeError::InvalidOperand); + } else if size == Size::B && byte & 0b1111 == 0b0011 { + // invalid dest, would be R1H + return Err(DecodeError::InvalidOperand); + } + + inst.operands[0] = OperandSpec::R1H; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + _ => { + unreachable!("opcode selector is four bits"); + } + } + + Ok(()) +} + +fn decode_op76<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + let opc_selector = byte >> 4; + if opc_selector < 0b1001 { + inst.opcode = [ + Opcode::TST(size), Opcode::XOR(size), Opcode::AND(size), + Opcode::OR(size), Opcode::ADD(size), Opcode::SUB(size), + Opcode::ADC(size), Opcode::SBB(size), Opcode::CMP(size) + ][opc_selector as usize]; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } else { + match opc_selector { + 0b1001 => { + inst.opcode = Opcode::DIVX(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + 0b1010 => { + inst.opcode = Opcode::ROLC; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1011 => { + inst.opcode = Opcode::RORC; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1100 => { + inst.opcode = Opcode::DIVU(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + 0b1101 => { + inst.opcode = Opcode::DIV(size); + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1110 => { + inst.opcode = Opcode::ADCF(size); + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + 0b1111 => { + inst.opcode = Opcode::ABS; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + _ => { + unreachable!("opcode selector is four bits"); + } + } + } + + Ok(()) +} + +fn decode_op78<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + inst.opcode = Opcode::MUL; + inst.operands[0] = Operand_RegDerefDispAbs(byte >> 4, size, inst, bytes)?; + let dest_code = byte & 0b1111; + match (size, dest_code) { + (Size::B, 0b0001) | + (Size::W, 0b0010) | + (_, 0b0011) | + (_, 0b0101) => { + return Err(DecodeError::InvalidOperand); + } + _ => {} + } + inst.operands[1] = Operand_RegDerefDispAbs(dest_code, size, inst, bytes)?; + + Ok(()) +} + +fn decode_op7A<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + if byte >= 0b10000000 { + inst.opcode = Opcode::LDC; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = Operand_IntFlgSpSbFb((byte >> 4) & 0b111)?; + } else { + inst.opcode = Opcode::XCHG(size); + assert_eq!(size, Size::B); + if byte >= 0b01000000 { + return Err(DecodeError::InvalidOperand); + } + inst.operands[0] = [ + OperandSpec::R0L, OperandSpec::R0H, + OperandSpec::R1L, OperandSpec::R1H, + ][(byte >> 4) as usize]; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + + Ok(()) +} + +fn decode_op7B<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + if byte >= 0b10000000 { + inst.opcode = Opcode::STC; + inst.operands[1] = Operand_IntFlgSpSbFb((byte >> 4) & 0b111)?; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } else { + inst.opcode = Opcode::XCHG(size); + assert_eq!(size, Size::W); + if byte >= 0b01000000 { + return Err(DecodeError::InvalidOperand); + } + inst.operands[0] = [ + OperandSpec::R0, OperandSpec::R1, + OperandSpec::R2, OperandSpec::R3, + ][(byte >> 4) as usize]; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + + Ok(()) +} + +fn decode_op7C<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + match byte >> 4 { + op @ 0b0000 | + op @ 0b0001 | + op @ 0b0010 | + op @ 0b0011 => { + inst.opcode = [ + Opcode::MOVLL, Opcode::MOVLH, + Opcode::MOVHL, Opcode::MOVHH, + ][op as usize]; + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::R0L; + }, + 0b0100 => { + inst.opcode = Opcode::MULU(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = Operand_RegDerefDispAbs(byte >> 4, size, inst, bytes)?; + let dest_code = byte & 0b1111; + match (size, dest_code) { + (Size::B, 0b0001) | + (Size::W, 0b0010) | + (_, 0b0011) | + (_, 0b0101) => { + return Err(DecodeError::InvalidOperand); + } + _ => {} + } + // careful! imm comes after dest disp/abs + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + }, + 0b0101 => { + inst.opcode = Opcode::MUL; + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = Operand_RegDerefDispAbs(byte >> 4, size, inst, bytes)?; + let dest_code = byte & 0b1111; + match (size, dest_code) { + (Size::B, 0b0001) | + (Size::W, 0b0010) | + (_, 0b0011) | + (_, 0b0101) => { + return Err(DecodeError::InvalidOperand); + } + _ => {} + } + // careful! imm comes after dest disp/abs + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + 0b0110 => { + // byte is 0b0110_xxxx + inst.opcode = Opcode::EXTS; + match byte & 0b1111 { + 0b0001 | + 0b0011 | + 0b0100 | + 0b0101 => { + return Err(DecodeError::InvalidOperand); + } + _ => {} + } + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + op @ 0b1000 | + op @ 0b1001 | + op @ 0b1010 | + op @ 0b1011 => { + inst.opcode = [ + Opcode::MOVLL, Opcode::MOVLH, + Opcode::MOVHL, Opcode::MOVHH, + ][(op & 0b11) as usize]; + inst.operands[0] = OperandSpec::R0L; + inst.operands[1] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + } + 0b1100 => { + inst.opcode = Opcode::EXTS; + let dest = match byte & 0b1111 { + 0b0010 | + 0b0011 | + 0b0101 => { + return Err(DecodeError::InvalidOperand); + } + 0b0000 => OperandSpec::R2R0, + 0b0001 => OperandSpec::R3R1, + 0b0100 => OperandSpec::A1A0, + code => { + Operand_RegDerefDispAbs(code, size, inst, bytes)? + } + }; + inst.operands[0] = dest; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1110 => { + let code = byte & 0b1111; + if code & 0b111 < 0b100 { + match code { + op @ 0b0000 | + op @ 0b0001 | + op @ 0b0010 | + op @ 0b0011 => { + inst.opcode = [ + Opcode::DIVU(size), Opcode::DIV(size), + Opcode::PUSH(size), Opcode::DIVX(size), + ][op as usize]; + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = OperandSpec::Nothing; + inst.operands[2] = OperandSpec::Nothing; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + op @ 0b1000 | + op @ 0b1001 | + op @ 0b1010 => { + inst.opcode = [ + Opcode::SMOVF(size), Opcode::SMOVB(size), + Opcode::SSTR(size), + ][(op & 0b11) as usize]; + inst.operands = [OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing]; + } + 0b1011 => { + inst.opcode = Opcode::ADD(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = OperandSpec::SP; + inst.operands[2] = OperandSpec::Nothing; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + _ => { unreachable!("this should be an invalid bit pattern"); } + } + } else { + inst.opcode = [ + Opcode::DADD, Opcode::DSUB, + Opcode::DADC, Opcode::DSBB, + ][(code & 0b11) as usize]; + if code < 0b1000 { + // reg-reg variants of these opcodes + inst.operands[0] = OperandSpec::R0H; + inst.operands[1] = OperandSpec::R0L; + } else { + // reg-imm8 variants of these opcodes + inst.operands[0] = OperandSpec::Imm8; + inst.operands[1] = OperandSpec::R0L; + assert_eq!(size, Size::B); + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + } + } + 0b1111 => { + match byte & 0b1111 { + 0b0000 => { + inst.opcode = Opcode::LDCTX; + inst.operands[0] = OperandSpec::Abs16; + inst.dispabs = read_imm(bytes, 2)? as u16; + inst.length += 2; + inst.operands[1] = OperandSpec::Abs20; + inst.imm_wide = read_imm(bytes, 3)? & 0x0f_ff_ff; + inst.length += 3; + } + 0b0001 => { + inst.opcode = Opcode::RMPA(size); + inst.operands[0] = OperandSpec::Nothing; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0010 => { + inst.opcode = Opcode::ENTER; + inst.operands[0] = OperandSpec::Imm8; + inst.imm_wide = read_imm(bytes, 1)?; + inst.length += 1; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0011 => { + inst.opcode = Opcode::EXTS; + inst.operands[0] = OperandSpec::R0; + inst.operands[1] = OperandSpec::Nothing; + } + _ => { + return Err(DecodeError::InvalidOpcode); + } + } + } + _ => { + return Err(DecodeError::InvalidOpcode); + } + } + + Ok(()) +} + +fn decode_op7D<T: Iterator<Item=u8>>(inst: &mut Instruction, size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + match byte >> 4 { + op @ 0b0000 | + op @ 0b0001 | + op @ 0b0010 | + op @ 0b0011 => { + inst.opcode = [ + Opcode::JMPI, Opcode::JSRI, + Opcode::JMPI, Opcode::JSRI, + ][op as usize]; + inst.operands[0] = Operand_RegDerefDisp20Abs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0100 => { + inst.opcode = Opcode::MULU(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = Operand_RegDerefDispAbs(byte >> 4, size, inst, bytes)?; + let dest_code = byte & 0b1111; + match (size, dest_code) { + (Size::B, 0b0001) | + (Size::W, 0b0010) | + (_, 0b0011) | + (_, 0b0101) => { + return Err(DecodeError::InvalidOperand); + } + _ => {} + } + // careful! imm comes after dest disp/abs + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + }, + 0b0101 => { + inst.opcode = Opcode::MUL; + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = Operand_RegDerefDispAbs(byte >> 4, size, inst, bytes)?; + let dest_code = byte & 0b1111; + match (size, dest_code) { + (Size::B, 0b0001) | + (Size::W, 0b0010) | + (_, 0b0011) | + (_, 0b0101) => { + return Err(DecodeError::InvalidOperand); + } + _ => {} + } + // careful! imm comes after dest disp/abs + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + 0b1001 => { + // byte is 0b1001_xxxx + if byte < 0b1001_1000 { + return Err(DecodeError::InvalidOperand); + } + // byte is 0b1001_1xxx + + inst.opcode = Opcode::PUSHA; + // while the low eight forms of this encoding are invalid, they would have been rejected above. + inst.operands[0] = Operand_RegDerefDispAbs(byte & 0b1111, size, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1010 => { + if byte >= 0b1010_1000 { + return Err(DecodeError::InvalidOperand); + } + inst.opcode = Opcode::LDIPL; + inst.operands[0] = OperandSpec::Imm8; + inst.operands[1] = OperandSpec::Nothing; + inst.imm_wide = ((((byte & 0b111) as i8) << 5) >> 5) as i32 as u32; + } + 0b1011 => { + // byte is 0b1011_xxxx + inst.opcode = Opcode::ADD(size); + inst.operands[0] = OperandSpec::Imm8; + inst.operands[1] = OperandSpec::SP; + inst.imm_wide = ((((byte & 0b111) as i8) << 4) >> 4) as i32 as u32; + } + 0b1100 => { + inst.opcode = match byte & 0b1111 { + 0b1000 => Opcode::JLE, + 0b1001 => Opcode::JO, + 0b1010 => Opcode::JGE, + 0b1100 => Opcode::JGT, + 0b1101 => Opcode::JNO, + 0b1110 => Opcode::JLT, + _ => { + return Err(DecodeError::InvalidOpcode); + } + }; + inst.operands[0] = OperandSpec::Disp8; + inst.operands[1] = OperandSpec::Nothing; + inst.imm_wide = read_imm(bytes, 1)?; + inst.length += 1; + } + 0b1101 => { + let code = byte & 0b1111; + if code == 0b1011 || code == 0b1111 { + return Err(DecodeError::InvalidOpcode); + } + // the NOP here fill gaps that are invalid encodings as tested above. + inst.opcode = [ + Opcode::BMGEU, Opcode::BMGTU, Opcode::BMEQ, Opcode::BMN, + Opcode::BMLTU, Opcode::BMLEU, Opcode::BMNE, Opcode::BMPZ, + Opcode::BMLE, Opcode::BMO, Opcode::GE, Opcode::NOP, + Opcode::BMGT, Opcode::NO, Opcode::LT, Opcode::NOP, + ][code as usize]; + inst.operands[0] = OperandSpec::Nothing; + inst.operands[1] = OperandSpec::Nothing; + } + 0b1110 => { + let code = byte & 0b1111; + if code & 0b111 < 0b100 { + match code { + op @ 0b0000 | + op @ 0b0001 | + op @ 0b0010 | + op @ 0b0011 => { + inst.opcode = [ + Opcode::DIVU(size), Opcode::DIV(size), + Opcode::PUSH(size), Opcode::DIVX(size), + ][op as usize]; + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = OperandSpec::Nothing; + inst.operands[2] = OperandSpec::Nothing; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + op @ 0b1000 | + op @ 0b1001 | + op @ 0b1010 => { + inst.opcode = [ + Opcode::SMOVF(size), Opcode::SMOVB(size), + Opcode::SSTR(size), + ][(op & 0b11) as usize]; + inst.operands = [OperandSpec::Nothing, OperandSpec::Nothing, OperandSpec::Nothing]; + } + 0b1011 => { + inst.opcode = Opcode::ADD(size); + inst.operands[0] = if size == Size::W { OperandSpec::Imm16 } else { OperandSpec::Imm8 }; + inst.operands[1] = OperandSpec::SP; + inst.operands[2] = OperandSpec::Nothing; + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + _ => { unreachable!("this should be an invalid bit pattern"); } + } + } else { + inst.opcode = [ + Opcode::DADD, Opcode::DSUB, + Opcode::DADC, Opcode::DSBB, + ][(code & 0b11) as usize]; + if code < 0b1000 { + // reg-reg variants of these opcodes + inst.operands[0] = OperandSpec::R1; + inst.operands[1] = OperandSpec::R0; + } else { + // reg-imm16 variants of these opcodes + inst.operands[0] = OperandSpec::Imm16; + inst.operands[1] = OperandSpec::R0; + assert_eq!(size, Size::W); + inst.imm_wide = read_imm(bytes, size.as_bytes())?; + inst.length += size.as_bytes(); + } + } + } + 0b1111 => { + // byte is 0b1111_xxxx + match byte & 0b1111 { + 0b0000 => { + inst.opcode = Opcode::STCTX; + inst.operands[0] = OperandSpec::Abs16; + inst.dispabs = read_imm(bytes, 2)? as u16; + inst.length += 2; + inst.operands[1] = OperandSpec::Abs20; + inst.imm_wide = read_imm(bytes, 3)? & 0x0f_ff_ff; + inst.length += 3; + } + 0b0001 => { + inst.opcode = Opcode::RMPA(size); + inst.operands[0] = OperandSpec::Nothing; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0010 => { + inst.opcode = Opcode::EXITD; + inst.operands[0] = OperandSpec::Nothing; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0011 => { + inst.opcode = Opcode::WAIT; + inst.operands[0] = OperandSpec::Nothing; + inst.operands[1] = OperandSpec::Nothing; + } + _ => { + return Err(DecodeError::InvalidOpcode); + } + } + } + _ => { + return Err(DecodeError::InvalidOpcode); + } + } + + Ok(()) +} + +fn decode_op7E<T: Iterator<Item=u8>>(inst: &mut Instruction, _size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + let op = byte >> 4; + let code = byte & 0b1111; + if op > 0b1101 { + return Err(DecodeError::InvalidOpcode); + } + if op == 0b0010 { + // handle BMCMD specifically + inst.operands[0] = Operand_BitRegDerefDispAbs(code, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + let cnd = read_imm(bytes, 1)? as u8; + inst.length += 1; + inst.opcode = match cnd { + 0b0000_0000 => Opcode::BMGEU, + 0b0000_0001 => Opcode::BMGTU, + 0b0000_0010 => Opcode::BMEQ, + 0b0000_0011 => Opcode::BMN, + 0b0000_0100 => Opcode::BMLE, + 0b0000_0101 => Opcode::BMO, + 0b0000_0110 => Opcode::BMGE, + 0b1111_1000 => Opcode::BMLTU, + 0b1111_1001 => Opcode::BMLEU, + 0b1111_1010 => Opcode::BMNE, + 0b1111_1011 => Opcode::BMPZ, + 0b1111_1100 => Opcode::BMGT, + 0b1111_1101 => Opcode::BMNO, + 0b1111_1110 => Opcode::BMLT, + _ => { + return Err(DecodeError::InvalidOpcode); + } + }; + } else { + inst.opcode = [ + Opcode::BTSTC, Opcode::BTSTS, Opcode::NOP, // NOP is unreachable, tested above + Opcode::BNTST, Opcode::BAND, Opcode::BNAND, + Opcode::BOR, Opcode::BNOR, Opcode::BCLR, + Opcode::BSET, Opcode::BNOT, Opcode::BTST, + Opcode::BXOR, Opcode::BNXOR, + ][op as usize]; + inst.operands[0] = Operand_BitRegDerefDispAbs(code, inst, bytes)?; + inst.operands[1] = OperandSpec::Nothing; + } + + Ok(()) +} + +fn decode_opEB<T: Iterator<Item=u8>>(inst: &mut Instruction, _size: Size, bytes: &mut T) -> Result<(), DecodeError> { + let byte = bytes.next().ok_or(DecodeError::ExhaustedInput)?; + inst.length += 1; + let upper = byte >> 4; + let lower = byte & 0b1111; + if upper < 0b1000 { + // SHL, SHA, LDC, POPC, MOVA, PUSHC, FSET, or FCLR + match lower { + 0b0000 => { + // LDC + inst.opcode = Opcode::LDC; + inst.operands[0] = OperandSpec::Imm16; + inst.operands[1] = Operand_IntFlgSpSbFb((byte >> 4) & 0b111)?; + inst.imm_wide = read_imm(bytes, 2)?; + inst.length += 2; + } + 0b0001 => { + // SHL/SHA + inst.opcode = if upper & 2 == 0 { Opcode::SHL(Size::L) } else { Opcode::SHA(Size::L) }; + inst.operands[0] = OperandSpec::R1H; + inst.operands[1] = if upper & 1 == 0 { OperandSpec::R2R0 } else { OperandSpec::R3R1 }; + } + 0b0010 => { + // PUSHC + inst.opcode = Opcode::PUSHC; + inst.operands[0] = Operand_IntFlgSpSbFb((byte >> 4) & 0b111)?; + inst.operands[1] = OperandSpec::Nothing; + }, + 0b0011 => { + // POPC + inst.opcode = Opcode::POPC; + inst.operands[0] = Operand_IntFlgSpSbFb((byte >> 4) & 0b111)?; + inst.operands[1] = OperandSpec::Nothing; + } + 0b0100 => { + // FSET + } + 0b0101 => { + // FCLR + } + _ => { + // MOVA + inst.opcode = Opcode::MOVA; + let src = byte & 0b1111; + if src < 0b1000 { + return Err(DecodeError::InvalidOperand); + } + inst.operands[0] = Operand_RegDerefDispAbs(src, Size::W, inst, bytes)?; + let dest = byte >> 4; + if dest >= 0b1000 { + return Err(DecodeError::InvalidOperand); + } + inst.operands[1] = Operand_RegDerefDispAbs(dest, Size::W, inst, bytes)?; + } + } + } else { + // SHL Imm4, SHA Imm4, or INT + if upper >= 0b1100 { + inst.opcode = Opcode::INT; + inst.operands[0] = OperandSpec::Imm8; + inst.operands[1] = OperandSpec::Nothing; + inst.imm_wide = (byte & 0b0011_1111) as u32; + } else { + inst.opcode = if upper & 2 == 0 { Opcode::SHL(Size::L) } else { Opcode::SHA(Size::L) }; + inst.operands[0] = OperandSpec::Imm4; + inst.imm_wide = lower as u32; + inst.operands[1] = if upper & 1 == 0 { OperandSpec::R2R0 } else { OperandSpec::R3R1 }; + } + } + + Ok(()) +} + +fn read_imm<T: Iterator<Item=u8>>(bytes: &mut T, mut size: u8) -> Result<u32, DecodeError> { + let mut imm: u32 = 0; + let mut offset = 0; + + while size > 0 { + imm |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u32) << (8 * offset); + offset += 1; + size -= 1; + } + + Ok(imm) +} + + +fn Operand_BitRegDerefDispAbs<T: Iterator<Item=u8>>(code: u8, inst: &mut Instruction, bytes: &mut T) -> Result<OperandSpec, DecodeError> { + use OperandSpec::*; + // "bit,<reg>" addressing modes taking their bit selector from a following byte is left mostly + // unspoken in the manual, aside from the "bit,Rn" and "bit,An" modes taking an extra byte. + let (imm_size, spec) = match code { + 0b0000 => (1, Bit_R0), + 0b0001 => (1, Bit_R1), + 0b0010 => (1, Bit_R2), + 0b0011 => (1, Bit_R3), + 0b0100 => (1, Bit_A0), + 0b0101 => (1, Bit_A1), + 0b0110 => (0, Bit_Deref_A0), + 0b0111 => (0, Bit_Deref_A1), + 0b1000 => (1, Bit_Disp8_A0), + 0b1001 => (1, Bit_Disp8_A1), + 0b1010 => (1, Bit_Disp8_SB), + 0b1011 => (1, Bit_Disp8_FB), + 0b1100 => (2, Bit_Disp16_A0), + 0b1101 => (2, Bit_Disp16_A1), + 0b1110 => (2, Bit_Disp16_SB), + 0b1111 => (2, Bit_Abs16), + _ => { unreachable!("invalid code provided, >0b1111"); } + }; + + if imm_size > 0 { + inst.dispabs = bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16; + inst.length += 1; + + if imm_size == 2 { + inst.dispabs |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16) << 8; + inst.length += 1; + } + } + + Ok(spec) + +} + +fn Operand_RegDerefDispAbs<T: Iterator<Item=u8>>(code: u8, size: Size, inst: &mut Instruction, bytes: &mut T) -> Result<OperandSpec, DecodeError> { + use OperandSpec::*; + let (imm_size, spec) = match code { + 0b0000 => (0, { if size == Size::B { R0L } else { R0 } }), + 0b0001 => (0, { if size == Size::B { R0H } else { R1 } }), + 0b0010 => (0, { if size == Size::B { R1L } else { R2 } }), + 0b0011 => (0, { if size == Size::B { R1H } else { R3 } }), + 0b0100 => (0, A0), + 0b0101 => (0, A1), + 0b0110 => (0, Deref_A0), + 0b0111 => (0, Deref_A1), + 0b1000 => (1, Disp8_A0), + 0b1001 => (1, Disp8_A1), + 0b1010 => (1, Disp8_SB), + 0b1011 => (1, Disp8_FB), + 0b1100 => (2, Disp16_A0), + 0b1101 => (2, Disp16_A1), + 0b1110 => (2, Disp16_SB), + 0b1111 => (2, Abs16), + _ => { unreachable!("invalid code provided, >0b1111"); } + }; + + if imm_size > 0 { + inst.dispabs = bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16; + inst.length += 1; + + if imm_size == 2 { + inst.dispabs |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16) << 8; + inst.length += 1; + } + } + + Ok(spec) +} + +fn Operand_second_RegDerefDispAbs<T: Iterator<Item=u8>>(code: u8, size: Size, inst: &mut Instruction, bytes: &mut T) -> Result<OperandSpec, DecodeError> { + use OperandSpec::*; + let (imm_size, spec) = match code { + 0b0000 => (0, { if size == Size::B { R0L } else { R0 } }), + 0b0001 => (0, { if size == Size::B { R0H } else { R1 } }), + 0b0010 => (0, { if size == Size::B { R1L } else { R2 } }), + 0b0011 => (0, { if size == Size::B { R1H } else { R3 } }), + 0b0100 => (0, A0), + 0b0101 => (0, A1), + 0b0110 => (0, Deref_A0), + 0b0111 => (0, Deref_A1), + 0b1000 => (1, Disp2_8_A0), + 0b1001 => (1, Disp2_8_A1), + 0b1010 => (1, Disp2_8_SB), + 0b1011 => (1, Disp2_8_FB), + 0b1100 => (2, Disp2_16_A0), + 0b1101 => (2, Disp2_16_A1), + 0b1110 => (2, Disp2_16_SB), + 0b1111 => (2, Abs2_16), + _ => { unreachable!("invalid code provided, >0b1111"); } + }; + + if imm_size > 0 { + inst.imm_wide = bytes.next().ok_or(DecodeError::ExhaustedInput)? as u32; + inst.length += 1; + + if imm_size == 2 { + inst.imm_wide |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u32) << 8; + inst.length += 1; + } + } + + Ok(spec) +} + +fn Operand_RegDerefDisp20Abs<T: Iterator<Item=u8>>(code: u8, size: Size, inst: &mut Instruction, bytes: &mut T) -> Result<OperandSpec, DecodeError> { + use OperandSpec::*; + let (imm_size, spec) = match code { + 0b0000 => (0, { if size == Size::B { R0L } else { R0 } }), + 0b0001 => (0, { if size == Size::B { R0H } else { R1 } }), + 0b0010 => (0, { if size == Size::B { R1L } else { R2 } }), + 0b0011 => (0, { if size == Size::B { R1H } else { R3 } }), + 0b0100 => (0, A0), + 0b0101 => (0, A1), + 0b0110 => (0, Deref_A0), + 0b0111 => (0, Deref_A1), + 0b1000 => (1, Disp8_A0), + 0b1001 => (1, Disp8_A1), + 0b1010 => (1, Disp8_SB), + 0b1011 => (1, Disp8_FB), + 0b1100 => (3, Disp20_A0), + 0b1101 => (3, Disp20_A1), + 0b1110 => (2, Disp16_SB), + 0b1111 => (2, Abs16), + _ => { unreachable!("invalid code provided, >0b1111"); } + }; + + match imm_size { + 1 => { + inst.dispabs = bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16; + inst.length += 1; + } + 2 => { + inst.dispabs = bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16; + inst.dispabs |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u16) << 8; + inst.length += 2; + } + 3 => { + inst.imm_wide = bytes.next().ok_or(DecodeError::ExhaustedInput)? as u32; + inst.imm_wide |= (bytes.next().ok_or(DecodeError::ExhaustedInput)? as u32) << 8; + inst.imm_wide |= ((bytes.next().ok_or(DecodeError::ExhaustedInput)? & 0x0f) as u32) << 16; + inst.length += 3; + } + _ => { + unreachable!(); + } + } + + Ok(spec) +} + +fn Operand_IntFlgSpSbFb(code: u8) -> Result<OperandSpec, DecodeError> { + use OperandSpec::*; + + match code { + 0b001 => Ok(INTBL), + 0b010 => Ok(INTBH), + 0b011 => Ok(FLG), + 0b100 => Ok(ISP), + 0b101 => Ok(SP), + 0b110 => Ok(SB), + 0b111 => Ok(FB), + _ => Err(DecodeError::InvalidOperand) + } +} |