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// Copyright (C) 2003 Dolphin Project.
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License 2.0 for more details.
// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/
// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/
#include "x64Analyzer.h"
bool DisassembleMov(const unsigned char *codePtr, InstructionInfo &info, int accessType)
{
unsigned const char *startCodePtr = codePtr;
u8 rex = 0;
u8 codeByte = 0;
u8 codeByte2 = 0;
//Check for regular prefix
info.operandSize = 4;
info.zeroExtend = false;
info.signExtend = false;
info.hasImmediate = false;
info.isMemoryWrite = false;
int addressSize = 8;
u8 modRMbyte = 0;
u8 sibByte = 0;
bool hasModRM = false;
bool hasSIBbyte = false;
bool hasDisplacement = false;
int displacementSize = 0;
if (*codePtr == 0x66)
{
info.operandSize = 2;
codePtr++;
}
else if (*codePtr == 0x67)
{
addressSize = 4;
codePtr++;
}
//Check for REX prefix
if ((*codePtr & 0xF0) == 0x40)
{
rex = *codePtr;
if (rex & 8) //REX.W
{
info.operandSize = 8;
}
codePtr++;
}
codeByte = *codePtr++;
// Skip two-byte opcode byte
bool twoByte = false;
if(codeByte == 0x0F)
{
twoByte = true;
codeByte2 = *codePtr++;
}
if (!twoByte)
{
if ((codeByte & 0xF0) == 0x80 ||
((codeByte & 0xF8) == 0xC0 && (codeByte & 0x0E) != 0x02))
{
modRMbyte = *codePtr++;
hasModRM = true;
}
}
else
{
if (((codeByte2 & 0xF0) == 0x00 && (codeByte2 & 0x0F) >= 0x04 && (codeByte2 & 0x0D) != 0x0D) ||
(codeByte2 & 0xF0) == 0x30 ||
codeByte2 == 0x77 ||
(codeByte2 & 0xF0) == 0x80 ||
((codeByte2 & 0xF0) == 0xA0 && (codeByte2 & 0x07) <= 0x02) ||
(codeByte2 & 0xF8) == 0xC8)
{
// No mod R/M byte
}
else
{
modRMbyte = *codePtr++;
hasModRM = true;
}
}
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;
hasSIBbyte = true;
}
else
{
//info.scaledReg =
}
}
if (mrm.mod == 1 || mrm.mod == 2)
{
hasDisplacement = true;
if (mrm.mod == 1)
displacementSize = 1;
else
displacementSize = 4;
}
}
if (displacementSize == 1)
info.displacement = (s32)(s8)*codePtr;
else
info.displacement = *((s32 *)codePtr);
codePtr += displacementSize;
if (accessType == 1)
{
info.isMemoryWrite = true;
//Write access
switch (codeByte)
{
case MOVE_8BIT: //move 8-bit immediate
{
info.hasImmediate = true;
info.immediate = *codePtr;
codePtr++; //move past immediate
}
break;
case MOVE_16_32BIT: //move 16 or 32-bit immediate, easiest case for writes
{
if (info.operandSize == 2)
{
info.hasImmediate = true;
info.immediate = *(u16*)codePtr;
codePtr += 2;
}
else if (info.operandSize == 4)
{
info.hasImmediate = true;
info.immediate = *(u32*)codePtr;
codePtr += 4;
}
else if (info.operandSize == 8)
{
info.zeroExtend = true;
info.immediate = *(u32*)codePtr;
codePtr += 4;
}
}
break;
case MOVE_REG_TO_MEM: //move reg to memory
break;
default:
PanicAlert("Unhandled disasm case in write handler!\n\nPlease implement or avoid.");
return false;
}
}
else
{
// Memory read
//mov eax, dword ptr [rax] == 8b 00
switch (codeByte)
{
case 0x0F:
switch (codeByte2)
{
case MOVZX_BYTE: //movzx on byte
info.zeroExtend = true;
info.operandSize = 1;
break;
case MOVZX_SHORT: //movzx on short
info.zeroExtend = true;
info.operandSize = 2;
break;
case MOVSX_BYTE: //movsx on byte
info.signExtend = true;
info.operandSize = 1;
break;
case MOVSX_SHORT: //movsx on short
info.signExtend = true;
info.operandSize = 2;
break;
default:
return false;
}
break;
case 0x8a:
if (info.operandSize == 4)
{
info.operandSize = 1;
break;
}
else
return false;
case 0x8b:
break; //it's OK don't need to do anything
default:
return false;
}
}
info.instructionSize = (int)(codePtr - startCodePtr);
return true;
}
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