diff options
Diffstat (limited to 'disassembler/disassembler_x86.cc')
| -rw-r--r-- | disassembler/disassembler_x86.cc | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/disassembler/disassembler_x86.cc b/disassembler/disassembler_x86.cc index e6cbf05744..61d5c81837 100644 --- a/disassembler/disassembler_x86.cc +++ b/disassembler/disassembler_x86.cc @@ -201,7 +201,8 @@ size_t DisassemblerX86::DumpInstruction(std::ostream& os, const uint8_t* instr) std::ostringstream opcode; bool store = false; // stores to memory (ie rm is on the left) bool load = false; // loads from memory (ie rm is on the right) - bool byte_operand = false; + bool byte_operand = false; // true when the opcode is dealing with byte operands + bool byte_second_operand = false; // true when the source operand is a byte register but the target register isn't (ie movsxb/movzxb). bool target_specific = false; // register name depends on target (64 vs 32 bits). bool ax = false; // implicit use of ax bool cx = false; // implicit use of cx @@ -732,9 +733,9 @@ DISASSEMBLER_ENTRY(cmp, break; case 0xAF: opcode << "imul"; has_modrm = true; load = true; break; case 0xB1: opcode << "cmpxchg"; has_modrm = true; store = true; break; - case 0xB6: opcode << "movzxb"; has_modrm = true; load = true; break; + case 0xB6: opcode << "movzxb"; has_modrm = true; load = true; byte_second_operand = true; break; case 0xB7: opcode << "movzxw"; has_modrm = true; load = true; break; - case 0xBE: opcode << "movsxb"; has_modrm = true; load = true; break; + case 0xBE: opcode << "movsxb"; has_modrm = true; load = true; byte_second_operand = true; rex |= (rex == 0 ? 0 : 0b1000); break; case 0xBF: opcode << "movsxw"; has_modrm = true; load = true; break; case 0xC5: if (prefix[2] == 0x66) { @@ -1124,7 +1125,8 @@ DISASSEMBLER_ENTRY(cmp, } else { if (mod == 3) { if (!no_ops) { - DumpRmReg(address, rex_w, rm, byte_operand, prefix[2], load ? src_reg_file : dst_reg_file); + DumpRmReg(address, rex_w, rm, byte_operand || byte_second_operand, + prefix[2], load ? src_reg_file : dst_reg_file); } } else { address << "["; |