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// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
#include "Common/x64Analyzer.h"
bool DisassembleMov(const unsigned char* codePtr, InstructionInfo* info)
{
unsigned const char* startCodePtr = codePtr;
u8 rex = 0;
u32 opcode;
int opcode_length;
//Check for regular prefix
info->operandSize = 4;
info->zeroExtend = false;
info->signExtend = false;
info->hasImmediate = false;
info->isMemoryWrite = false;
info->byteSwap = false;
u8 modRMbyte = 0;
u8 sibByte = 0;
bool hasModRM = false;
int displacementSize = 0;
if (*codePtr == 0x66)
{
info->operandSize = 2;
codePtr++;
}
else if (*codePtr == 0x67)
{
codePtr++;
}
//Check for REX prefix
if ((*codePtr & 0xF0) == 0x40)
{
rex = *codePtr;
if (rex & 8) //REX.W
{
info->operandSize = 8;
}
codePtr++;
}
opcode = *codePtr++;
opcode_length = 1;
if (opcode == 0x0F)
{
opcode = (opcode << 8) | *codePtr++;
opcode_length = 2;
if ((opcode & 0xFB) == 0x38)
{
opcode = (opcode << 8) | *codePtr++;
opcode_length = 3;
}
}
switch (opcode_length)
{
case 1:
if ((opcode & 0xF0) == 0x80 ||
((opcode & 0xF8) == 0xC0 && (opcode & 0x0E) != 0x02))
{
modRMbyte = *codePtr++;
hasModRM = true;
}
break;
case 2:
if (((opcode & 0xF0) == 0x00 && (opcode & 0x0F) >= 0x04 && (opcode & 0x0D) != 0x0D) ||
((opcode & 0xF0) == 0xA0 && (opcode & 0x07) <= 0x02) ||
(opcode & 0xF0) == 0x30 ||
(opcode & 0xFF) == 0x77 ||
(opcode & 0xF0) == 0x80 ||
(opcode & 0xF8) == 0xC8)
{
// No mod R/M byte
}
else
{
modRMbyte = *codePtr++;
hasModRM = true;
}
break;
case 3:
// TODO: support more 3-byte opcode instructions
if ((opcode & 0xFE) == 0xF0)
{
modRMbyte = *codePtr++;
hasModRM = true;
}
break;
}
if (hasModRM)
{
ModRM mrm(modRMbyte, rex);
info->regOperandReg = mrm.reg;
if (mrm.mod < 3)
{
if (mrm.rm == 4)
{
//SIB byte
sibByte = *codePtr++;
info->scaledReg = (sibByte >> 3) & 7;
info->otherReg = (sibByte & 7);
if (rex & 2) info->scaledReg += 8;
if (rex & 1) info->otherReg += 8;
}
else
{
//info->scaledReg =
}
}
if (mrm.mod == 1 || mrm.mod == 2)
{
if (mrm.mod == 1)
displacementSize = 1;
else
displacementSize = 4;
}
}
if (displacementSize == 1)
info->displacement = (s32)(s8)*codePtr;
else
info->displacement = *((s32*)codePtr);
codePtr += displacementSize;
switch (opcode)
{
case 0xC6: // mem <- imm8
info->isMemoryWrite = true;
info->hasImmediate = true;
info->immediate = *codePtr;
info->operandSize = 1;
codePtr++;
break;
case 0xC7: // mem <- imm16/32
info->isMemoryWrite = true;
switch (info->operandSize)
{
case 2:
info->hasImmediate = true;
info->immediate = *(u16*)codePtr;
codePtr += 2;
break;
case 4:
info->hasImmediate = true;
info->immediate = *(u32*)codePtr;
codePtr += 4;
break;
case 8:
info->zeroExtend = true;
info->immediate = *(u32*)codePtr;
codePtr += 4;
break;
}
break;
case 0x88: // mem <- r8
info->isMemoryWrite = true;
if (info->operandSize != 4)
{
return false;
}
info->operandSize = 1;
break;
case 0x89: // mem <- r16/32/64
info->isMemoryWrite = true;
break;
case 0x8A: // r8 <- mem
if (info->operandSize != 4)
{
return false;
}
info->operandSize = 1;
break;
case 0x8B: // r16/32/64 <- mem
break;
case 0x0FB6: // movzx on byte
info->zeroExtend = true;
info->operandSize = 1;
break;
case 0x0FB7: // movzx on short
info->zeroExtend = true;
info->operandSize = 2;
break;
case 0x0FBE: // movsx on byte
info->signExtend = true;
info->operandSize = 1;
break;
case 0x0FBF: // movsx on short
info->signExtend = true;
info->operandSize = 2;
break;
case 0x0F38F0: // movbe read
info->byteSwap = true;
break;
case 0x0F38F1: // movbe write
info->byteSwap = true;
info->isMemoryWrite = true;
break;
default:
return false;
}
info->instructionSize = (int)(codePtr - startCodePtr);
return true;
}
bool InstructionInfo::operator==(const InstructionInfo& other) const
{
return operandSize == other.operandSize &&
instructionSize == other.instructionSize &&
regOperandReg == other.regOperandReg &&
otherReg == other.otherReg &&
scaledReg == other.scaledReg &&
zeroExtend == other.zeroExtend &&
signExtend == other.signExtend &&
hasImmediate == other.hasImmediate &&
isMemoryWrite == other.isMemoryWrite &&
byteSwap == other.byteSwap &&
immediate == other.immediate &&
displacement == other.displacement;
}
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