reallocate OperandCode, convert disparate registers to array

also remove redundant assignments of operand_count and some OperandSpec,
bulk-assign all registers and operands on entry to `read_instr`. this
all, taken together, shaves off about 7 cycles per decode.

1 files changed, 105 insertions, 105 deletions

diff --git a/src/protected_mode/vex.rs b/src/protected_mode/vex.rs
index 2f871c6..235d160 100644
--- a/src/protected_mode/vex.rs
+++ b/src/protected_mode/vex.rs
@@ -117,7 +117,7 @@ pub(crate) fn three_byte_vex<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <A
             return Err(DecodeError::InvalidOpcode);
         }
     };
-    instruction.vex_reg = RegSpec {
+    instruction.regs[3] = RegSpec {
         bank: RegisterBank::X,
         num: ((vex_byte_two >> 3) & 0b1111) ^ 0b1111,
     };
@@ -125,7 +125,7 @@ pub(crate) fn three_byte_vex<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <A
 
     read_vex_instruction(m, words, instruction, p)?;
     instruction.length = words.offset() as u8;
-    instruction.vex_reg.num &= 0b0111; // ignore bit 4 in 32-bit mode
+    instruction.regs[3].num &= 0b0111; // ignore bit 4 in 32-bit mode
     Ok(())
 }
 
@@ -138,7 +138,7 @@ pub(crate) fn two_byte_vex<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arc
         0x03 => VEXOpcodePrefix::PrefixF2,
         _ => { unreachable!("p is two bits"); }
     };
-    instruction.vex_reg = RegSpec {
+    instruction.regs[3] = RegSpec {
         bank: RegisterBank::X,
         num: ((vex_byte >> 3) & 0b1111) ^ 0b1111,
     };
@@ -146,7 +146,7 @@ pub(crate) fn two_byte_vex<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arc
 
     read_vex_instruction(VEXOpcodeMap::Map0F, words, instruction, p)?;
     instruction.length = words.offset() as u8;
-    instruction.vex_reg.num &= 0b0111; // ignore bit 4 in 32-bit mode
+    instruction.regs[3].num &= 0b0111; // ignore bit 4 in 32-bit mode
     Ok(())
 }
 
@@ -173,9 +173,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOpcode);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts(modrm & 7, RegisterBank::X);
-            instruction.vex_reg.bank = RegisterBank::X;
+            instruction.regs[3].bank = RegisterBank::X;
             instruction.operands[0] = OperandSpec::RegVex;
             instruction.operands[1] = OperandSpec::RegRRR;
             instruction.imm = read_imm_unsigned(words, 1)?;
@@ -206,9 +206,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOpcode);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts(modrm & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             instruction.operands[0] = OperandSpec::RegVex;
             instruction.operands[1] = OperandSpec::RegRRR;
             instruction.imm = read_imm_unsigned(words, 1)?;
@@ -236,9 +236,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOpcode);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts(modrm & 7, RegisterBank::X);
-            instruction.vex_reg.bank = RegisterBank::X;
+            instruction.regs[3].bank = RegisterBank::X;
             instruction.operands[0] = OperandSpec::RegVex;
             instruction.operands[1] = OperandSpec::RegRRR;
             instruction.imm = read_imm_unsigned(words, 1)?;
@@ -266,9 +266,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOpcode);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts(modrm & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             instruction.operands[0] = OperandSpec::RegVex;
             instruction.operands[1] = OperandSpec::RegRRR;
             instruction.imm = read_imm_unsigned(words, 1)?;
@@ -299,9 +299,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOpcode);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts(modrm & 7, RegisterBank::X);
-            instruction.vex_reg.bank = RegisterBank::X;
+            instruction.regs[3].bank = RegisterBank::X;
             instruction.operands[0] = OperandSpec::RegVex;
             instruction.operands[1] = OperandSpec::RegRRR;
             instruction.imm = read_imm_unsigned(words, 1)?;
@@ -338,9 +338,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     unreachable!("r is only three bits");
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts(modrm & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             instruction.operands[0] = OperandSpec::RegVex;
             instruction.operands[1] = OperandSpec::RegRRR;
             instruction.imm = read_imm_unsigned(words, 1)?;
@@ -351,7 +351,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         VEXOperandCode::VMOVSS_10 |
         VEXOperandCode::VMOVSD_10 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -362,7 +362,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     instruction.operand_count = 3;
                 },
                 other => {
-                    if instruction.vex_reg.num != 0 {
+                    if instruction.regs[3].num != 0 {
                         instruction.opcode = Opcode::Invalid;
                         return Err(DecodeError::InvalidOperand);
                     }
@@ -380,7 +380,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         VEXOperandCode::VMOVSS_11 |
         VEXOperandCode::VMOVSD_11 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[2] = OperandSpec::RegRRR;
@@ -391,7 +391,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     instruction.operand_count = 3;
                 },
                 other => {
-                    if instruction.vex_reg.num != 0 {
+                    if instruction.regs[3].num != 0 {
                         instruction.opcode = Opcode::Invalid;
                         return Err(DecodeError::InvalidOperand);
                     }
@@ -415,7 +415,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                 instruction.mem_size = 4;
                 Opcode::VMOVLPS
             };
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -431,7 +431,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                 instruction.mem_size = 8;
                 Opcode::VMOVHPS
             };
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -444,12 +444,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         },
         VEXOperandCode::Ev_G_xmm_imm8 => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E(words, instruction, modrm, 4)?;
             instruction.operands[0] = mem_oper;
@@ -477,12 +477,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         },
         VEXOperandCode::G_xmm_Ed => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E(words, instruction, modrm, 4)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -494,12 +494,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::Ed_G_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E(words, instruction, modrm, 4)?;
             instruction.operands[0] = mem_oper;
@@ -511,16 +511,16 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::VCVT_Gd_Ed_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
-            let mem_oper = read_E(words instruction, modrm, 4)?;
+            let mem_oper = read_E(words, instruction, modrm, 4)?;
             if let OperandSpec::RegMMM = mem_oper {
-                instruction.modrm_mmm.bank = RegisterBank::X;
+                instruction.regs[1].bank = RegisterBank::X;
             } else {
                 instruction.mem_size = 4;
             }
@@ -530,16 +530,16 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::VCVT_Gd_Eq_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
             let mem_oper = read_E(words, instruction, modrm, 4)?;
             if let OperandSpec::RegMMM = mem_oper {
-                instruction.modrm_mmm.bank = RegisterBank::X;
+                instruction.regs[1].bank = RegisterBank::X;
             } else {
                 instruction.mem_size = 8;
             }
@@ -550,12 +550,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         op @ VEXOperandCode::E_G_xmm |
         op @ VEXOperandCode::M_G_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             match (op, mem_oper) {
@@ -583,12 +583,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::Ud_G_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             if mem_oper != OperandSpec::RegMMM {
@@ -600,12 +600,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::Ud_G_ymm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             if mem_oper != OperandSpec::RegMMM {
@@ -617,12 +617,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::Ud_G_xmm_imm8 => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             if mem_oper != OperandSpec::RegMMM {
@@ -636,12 +636,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::E_G_xmm_imm8 => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = mem_oper;
@@ -655,12 +655,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::E_xmm_G_ymm_imm8 => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = mem_oper;
@@ -675,12 +675,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
 
         VEXOperandCode::Gd_U_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             if mem_oper != OperandSpec::RegMMM {
@@ -692,12 +692,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::Gd_U_ymm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::D);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             if mem_oper != OperandSpec::RegMMM {
@@ -712,7 +712,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         op @ VEXOperandCode::G_M_xmm |
         op @ VEXOperandCode::G_U_xmm |
         op @ VEXOperandCode::G_E_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
@@ -730,7 +730,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     /* and this is always accepted */
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -748,12 +748,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::G_xmm_E_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -765,12 +765,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::G_xmm_E_ymm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -783,7 +783,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         op @ VEXOperandCode::G_ymm_M_xmm |
         op @ VEXOperandCode::G_ymm_E_xmm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
@@ -793,7 +793,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOperand);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -811,12 +811,12 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::G_ymm_E_ymm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -830,7 +830,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
 
         op @ VEXOperandCode::E_G_ymm |
         op @ VEXOperandCode::M_G_ymm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
@@ -844,7 +844,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     /* and this is always accepted */
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = mem_oper;
@@ -858,7 +858,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
 
         op @ VEXOperandCode::G_M_ymm |
         op @ VEXOperandCode::G_E_ymm => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 instruction.opcode = Opcode::Invalid;
                 return Err(DecodeError::InvalidOperand);
             }
@@ -872,7 +872,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     /* and this is always accepted */
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -891,9 +891,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                     return Err(DecodeError::InvalidOperand);
                 }
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -906,9 +906,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_E_ymm_imm8 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -926,9 +926,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             if modrm & 0xc0 == 0xc0 {
                 return Err(DecodeError::InvalidOperand);
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = mem_oper;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -944,7 +944,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             if modrm & 0xc0 == 0xc0 {
                 return Err(DecodeError::InvalidOperand);
             }
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -962,7 +962,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_E_xmm => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -982,7 +982,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_xmm_Ed => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E(words, instruction, modrm, 4)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -996,7 +996,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_E_xmm_imm8 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -1012,9 +1012,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_ymm_V_ymm_E_xmm_imm8 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -1033,7 +1033,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                 return Err(DecodeError::InvalidOperand);
             }
 
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = mem_oper;
@@ -1048,10 +1048,10 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
 
         VEXOperandCode::G_Ex_V_xmm => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
-            instruction.sib_index.bank = RegisterBank::X;
+            instruction.regs[2].bank = RegisterBank::X;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = mem_oper;
             instruction.operands[2] = OperandSpec::RegVex;
@@ -1063,11 +1063,11 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_Ey_V_xmm => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
-            instruction.vex_reg.bank = RegisterBank::X;
-            instruction.sib_index.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::X;
+            instruction.regs[2].bank = RegisterBank::Y;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = mem_oper;
             instruction.operands[2] = OperandSpec::RegVex;
@@ -1079,11 +1079,11 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_Ey_V_ymm => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
-            instruction.vex_reg.bank = RegisterBank::Y;
-            instruction.sib_index.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
+            instruction.regs[2].bank = RegisterBank::Y;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = mem_oper;
             instruction.operands[2] = OperandSpec::RegVex;
@@ -1100,9 +1100,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         VEXOperandCode::G_V_E => {
             let modrm = read_modrm(words)?;
             let (opwidth, bank) = (4, RegisterBank::D);
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, bank);
-            instruction.vex_reg.bank = bank;
+            instruction.regs[3].bank = bank;
             let mem_oper = read_E(words, instruction, modrm, opwidth)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -1116,9 +1116,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         VEXOperandCode::G_E_V => {
             let modrm = read_modrm(words)?;
             let (opwidth, bank) = (4, RegisterBank::D);
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, bank);
-            instruction.vex_reg.bank = bank;
+            instruction.regs[3].bank = bank;
             let mem_oper = read_E(words, instruction, modrm, opwidth)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = mem_oper;
@@ -1132,7 +1132,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         VEXOperandCode::G_E_Ib => {
             let modrm = read_modrm(words)?;
             let (opwidth, bank) = (4, RegisterBank::D);
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, bank);
             let mem_oper = read_E(words, instruction, modrm, opwidth)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -1163,7 +1163,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
                 }
             };
             let (opwidth, bank) = (4, RegisterBank::D);
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, bank);
             let mem_oper = read_E(words, instruction, modrm, opwidth)?;
             instruction.operands[0] = OperandSpec::RegVex;
@@ -1172,7 +1172,7 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             if mem_oper != OperandSpec::RegMMM {
                 instruction.mem_size = opwidth;
             }
-            instruction.vex_reg.bank = bank;
+            instruction.regs[3].bank = bank;
             Ok(())
         }
         VEXOperandCode::MXCSR => {
@@ -1201,11 +1201,11 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::G_E_xmm_imm8 => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -1219,11 +1219,11 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
             Ok(())
         }
         VEXOperandCode::G_E_ymm_imm8 => {
-            if instruction.vex_reg.num != 0 {
+            if instruction.regs[3].num != 0 {
                 return Err(DecodeError::InvalidOperand);
             }
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
@@ -1238,9 +1238,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_E_ymm_ymm4 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             let mem_oper = read_E_ymm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -1255,9 +1255,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_E_xmm_xmm4 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
-            instruction.vex_reg.bank = RegisterBank::X;
+            instruction.regs[3].bank = RegisterBank::X;
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -1272,9 +1272,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_ymm_E_xmm => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::Y);
-            instruction.vex_reg.bank = RegisterBank::Y;
+            instruction.regs[3].bank = RegisterBank::Y;
             let mem_oper = read_E_xmm(words, instruction, modrm)?;
             instruction.operands[0] = OperandSpec::RegRRR;
             instruction.operands[1] = OperandSpec::RegVex;
@@ -1287,9 +1287,9 @@ fn read_vex_operands<T: Reader<<Arch as yaxpeax_arch::Arch>::Address, <Arch as y
         }
         VEXOperandCode::G_V_xmm_Ev_imm8 => {
             let modrm = read_modrm(words)?;
-            instruction.modrm_rrr =
+            instruction.regs[0] =
                 RegSpec::from_parts((modrm >> 3) & 7, RegisterBank::X);
-            instruction.vex_reg.bank = RegisterBank::X;
+            instruction.regs[3].bank = RegisterBank::X;
             // TODO: but the memory access is word-sized
             let mem_oper = read_E(words, instruction, modrm, 4)?;
             instruction.operands[0] = OperandSpec::RegRRR;