228 lines
4.0 KiB
C++
228 lines
4.0 KiB
C++
// Copyright 2013 Dolphin Emulator Project
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// Licensed under GPLv2
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// Refer to the license.txt file included.
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#include "x64Analyzer.h"
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bool DisassembleMov(const unsigned char *codePtr, InstructionInfo *info)
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{
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unsigned const char *startCodePtr = codePtr;
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u8 rex = 0;
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u8 codeByte = 0;
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u8 codeByte2 = 0;
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//Check for regular prefix
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info->operandSize = 4;
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info->zeroExtend = false;
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info->signExtend = false;
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info->hasImmediate = false;
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info->isMemoryWrite = false;
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u8 modRMbyte = 0;
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u8 sibByte = 0;
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bool hasModRM = false;
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int displacementSize = 0;
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if (*codePtr == 0x66)
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{
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info->operandSize = 2;
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codePtr++;
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}
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else if (*codePtr == 0x67)
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{
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codePtr++;
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}
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//Check for REX prefix
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if ((*codePtr & 0xF0) == 0x40)
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{
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rex = *codePtr;
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if (rex & 8) //REX.W
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{
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info->operandSize = 8;
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}
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codePtr++;
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}
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codeByte = *codePtr++;
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// Skip two-byte opcode byte
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bool twoByte = false;
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if(codeByte == 0x0F)
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{
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twoByte = true;
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codeByte2 = *codePtr++;
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}
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if (!twoByte)
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{
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if ((codeByte & 0xF0) == 0x80 ||
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((codeByte & 0xF8) == 0xC0 && (codeByte & 0x0E) != 0x02))
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{
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modRMbyte = *codePtr++;
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hasModRM = true;
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}
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}
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else
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{
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if (((codeByte2 & 0xF0) == 0x00 && (codeByte2 & 0x0F) >= 0x04 && (codeByte2 & 0x0D) != 0x0D) ||
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(codeByte2 & 0xF0) == 0x30 ||
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codeByte2 == 0x77 ||
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(codeByte2 & 0xF0) == 0x80 ||
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((codeByte2 & 0xF0) == 0xA0 && (codeByte2 & 0x07) <= 0x02) ||
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(codeByte2 & 0xF8) == 0xC8)
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{
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// No mod R/M byte
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}
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else
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{
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modRMbyte = *codePtr++;
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hasModRM = true;
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}
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}
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if (hasModRM)
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{
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ModRM mrm(modRMbyte, rex);
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info->regOperandReg = mrm.reg;
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if (mrm.mod < 3)
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{
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if (mrm.rm == 4)
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{
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//SIB byte
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sibByte = *codePtr++;
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info->scaledReg = (sibByte >> 3) & 7;
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info->otherReg = (sibByte & 7);
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if (rex & 2) info->scaledReg += 8;
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if (rex & 1) info->otherReg += 8;
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}
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else
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{
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//info->scaledReg =
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}
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}
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if (mrm.mod == 1 || mrm.mod == 2)
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{
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if (mrm.mod == 1)
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displacementSize = 1;
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else
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displacementSize = 4;
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}
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}
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if (displacementSize == 1)
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info->displacement = (s32)(s8)*codePtr;
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else
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info->displacement = *((s32 *)codePtr);
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codePtr += displacementSize;
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switch (codeByte)
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{
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// writes
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case 0xC6: // mem <- imm8
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{
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info->isMemoryWrite = true;
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info->hasImmediate = true;
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info->immediate = *codePtr;
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codePtr++; //move past immediate
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}
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break;
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case 0xC7: // mem <- imm16/32
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{
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info->isMemoryWrite = true;
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if (info->operandSize == 2)
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{
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info->hasImmediate = true;
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info->immediate = *(u16*)codePtr;
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codePtr += 2;
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}
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else if (info->operandSize == 4)
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{
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info->hasImmediate = true;
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info->immediate = *(u32*)codePtr;
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codePtr += 4;
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}
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else if (info->operandSize == 8)
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{
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info->zeroExtend = true;
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info->immediate = *(u32*)codePtr;
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codePtr += 4;
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}
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}
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case 0x88: // mem <- r8
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{
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info->isMemoryWrite = true;
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if (info->operandSize == 4)
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{
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info->operandSize = 1;
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break;
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}
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else
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return false;
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break;
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}
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case 0x89: // mem <- r16/32/64
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{
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info->isMemoryWrite = true;
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break;
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}
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case 0x0F: // two-byte escape
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{
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info->isMemoryWrite = false;
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switch (codeByte2)
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{
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case 0xB6: // movzx on byte
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info->zeroExtend = true;
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info->operandSize = 1;
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break;
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case 0xB7: // movzx on short
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info->zeroExtend = true;
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info->operandSize = 2;
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break;
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case 0xBE: // movsx on byte
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info->signExtend = true;
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info->operandSize = 1;
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break;
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case 0xBF: // movsx on short
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info->signExtend = true;
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info->operandSize = 2;
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break;
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default:
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return false;
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}
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break;
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}
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case 0x8A: // r8 <- mem
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{
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info->isMemoryWrite = false;
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if (info->operandSize == 4)
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{
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info->operandSize = 1;
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break;
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}
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else
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return false;
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}
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case 0x8B: // r16/32/64 <- mem
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{
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info->isMemoryWrite = false;
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break;
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}
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break;
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default:
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return false;
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}
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info->instructionSize = (int)(codePtr - startCodePtr);
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return true;
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}
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