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Cxbx-Reloaded
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Refactored EmuX86_MOV

This commit is contained in:
PatrickvL 2016-12-02 18:48:03 +01:00
parent 6071e81ebf
commit 1fea5aaf1b
1 changed files with 84 additions and 90 deletions
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174
src/CxbxKrnl/EmuX86.cpp
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@ -138,94 +138,96 @@ inline bool EmuX86_DecodeMemoryOperand(uint32_t* output, LPEXCEPTION_POINTERS e,
bool EmuX86_MOV(LPEXCEPTION_POINTERS e, Zydis::InstructionInfo& info)
{
if (info.operand[0].type == Zydis::OperandType::REGISTER && info.operand[1].type == Zydis::OperandType::MEMORY)
// TODO : Test this refactoring
// Retrieve source value :
uint32_t value = 0;
switch (info.operand[1].type) {
// TODO : case Zydis::OperandType::CONSTANT:
// TODO : case Zydis::OperandType::POINTER:
// TODO : case Zydis::OperandType::REL_IMMEDIATE:
case Zydis::OperandType::IMMEDIATE:
value = info.operand[1].lval.udword;
break;
case Zydis::OperandType::REGISTER:
{
if (!EmuX86_GetRegisterValue(&value, e, info.operand[1].base))
return false;
break;
}
case Zydis::OperandType::MEMORY:
{
DWORD* pDstReg = nullptr;
uint32_t srcAddr = 0;
pDstReg = EmuX86_GetRegisterPointer(e, info.operand[0].base);
if (pDstReg == nullptr) {
if (!EmuX86_DecodeMemoryOperand(&srcAddr, e, info.operand[1]))
return false;
}
if (!EmuX86_DecodeMemoryOperand(&srcAddr, e, info.operand[1])) {
return false;
}
switch (info.operand[0].size) {
case 8:
*((uint8_t*)pDstReg + 3) = EmuX86_Read8(srcAddr);;
break;
case 16:
*((uint16_t*)pDstReg + 2) = EmuX86_Read16(srcAddr);
break;
case 32:
*pDstReg = EmuX86_Read32(srcAddr);
break;
default:
return false;
}
}
else if (info.operand[0].type == Zydis::OperandType::MEMORY && info.operand[1].type == Zydis::OperandType::REGISTER)
{
uint32_t addr = 0;
uint32_t value = 0;
if (!EmuX86_DecodeMemoryOperand(&addr, e, info.operand[0])) {
return false;
}
if (!EmuX86_GetRegisterValue(&value, e, info.operand[1].base)) {
return false;
}
switch (info.operand[0].size) {
case 8:
EmuX86_Write8(addr, value & 0xFF);
break;
case 16:
EmuX86_Write16(addr, value & 0xFFFF);
break;
case 32:
EmuX86_Write32(addr, value);
break;
default:
return false;
}
}
else if (info.operand[0].type == Zydis::OperandType::MEMORY && info.operand[1].type == Zydis::OperandType::IMMEDIATE)
{
uint32_t addr = 0;
if (!EmuX86_DecodeMemoryOperand(&addr, e, info.operand[0])) {
return false;
}
switch (info.operand[0].size) {
case 8:
EmuX86_Write8(addr, info.operand[1].lval.ubyte);
value = EmuX86_Read8(srcAddr);;
break;
case 16:
EmuX86_Write16(addr, info.operand[1].lval.uword);
value = EmuX86_Read16(srcAddr);
break;
case 32:
EmuX86_Write32(addr, info.operand[1].lval.udword);
value = EmuX86_Read32(srcAddr);
break;
default:
return false;
}
}
else
default:
return false;
/* TODO : What flags need to be set at a successfull MOV ?
}
// Write value to destination :
switch (info.operand[0].type) {
case Zydis::OperandType::REGISTER:
{
DWORD* pDstReg = EmuX86_GetRegisterPointer(e, info.operand[0].base);
if (pDstReg == nullptr)
return false;
switch (info.operand[0].size) {
case 8:
*((uint8_t*)pDstReg + 3) = value & 0xFF;
break;
case 16:
*((uint16_t*)pDstReg + 2) = value & 0xFFFF;
break;
case 32:
*pDstReg = value;
break;
default:
return false;
}
}
case Zydis::OperandType::MEMORY:
{
uint32_t destAddr = 0;
if (!EmuX86_DecodeMemoryOperand(&destAddr, e, info.operand[0]))
return false;
switch (info.operand[0].size) {
case 8:
EmuX86_Write8(destAddr, value & 0xFF);
break;
case 16:
EmuX86_Write16(destAddr, value & 0xFFFF);
break;
case 32:
EmuX86_Write32(destAddr, value);
break;
default:
return false;
}
}
default:
return false;
}
// Note : MOV instructions never update CPU flags
EmuX86_SetFlag(e, EMUX86_EFLAG_CF, 0);
EmuX86_SetFlag(e, EMUX86_EFLAG_OF, 0);
EmuX86_SetFlag(e, EMUX86_EFLAG_SF, 0);
EmuX86_SetFlag(e, EMUX86_EFLAG_ZF, 0);
EmuX86_SetFlag(e, EMUX86_EFLAG_PF, 0);
*/
return true;
}
@ -237,27 +239,21 @@ inline void EmuX86_SetFlag(LPEXCEPTION_POINTERS e, int flag, int value)
bool EmuX86_TEST(LPEXCEPTION_POINTERS e, Zydis::InstructionInfo& info)
{
uint32_t result = 0;
bool handled = false;
uint32_t value = 0;
if (info.operand[0].type == Zydis::OperandType::MEMORY && info.operand[1].type == Zydis::OperandType::IMMEDIATE)
{
uint32_t addr = 0;
if (!EmuX86_DecodeMemoryOperand(&addr, e, info.operand[0])) {
return false;
}
uint32_t value = EmuX86_Read32(addr);
// Perform bitwise AND
result = value & info.operand[1].lval.udword;
handled = true;
value = EmuX86_Read32(addr);
result = info.operand[1].lval.udword;
}
else if (info.operand[0].type == Zydis::OperandType::MEMORY && info.operand[1].type == Zydis::OperandType::REGISTER)
{
uint32_t addr = 0;
uint32_t value = 0;
if (!EmuX86_DecodeMemoryOperand(&addr, e, info.operand[0])) {
return false;
}
@ -266,24 +262,20 @@ bool EmuX86_TEST(LPEXCEPTION_POINTERS e, Zydis::InstructionInfo& info)
return false;
}
// Perform bitwise AND
result = EmuX86_Read32(addr) & value;
handled = true;
result = EmuX86_Read32(addr);
}
if (!handled) {
else
return false;
}
// Perform bitwise AND
result &= value;
// https://en.wikipedia.org/wiki/TEST_(x86_instruction)
// Set CF/OF to 0
// TODO FIXME using http://www.emulators.com/docs/nx11_flags.htm#Faster_Lazy_Evaluation
EmuX86_SetFlag(e, EMUX86_EFLAG_CF, 0);
EmuX86_SetFlag(e, EMUX86_EFLAG_OF, 0);
EmuX86_SetFlag(e, EMUX86_EFLAG_SF, result >> 31);
EmuX86_SetFlag(e, EMUX86_EFLAG_ZF, result == 0 ? 1 : 0);
// Set Parity flag, based on "Compute parity in parallel" method from
// http://graphics.stanford.edu/~seander/bithacks.html#ParityParallel
uint32_t v = 255 & result;
@ -291,6 +283,8 @@ bool EmuX86_TEST(LPEXCEPTION_POINTERS e, Zydis::InstructionInfo& info)
v &= 0xf;
EmuX86_SetFlag(e, EMUX86_EFLAG_PF, (0x6996 >> v) & 1);
// result is thrown away
return true;
}