private static void GetBranchTarget(Instruction instruction, CodeContext context, GpRegister target)
{
var operand = instruction.Operands.First();
switch (operand.Type)
{
case ud_type.UD_OP_REG:
var maybeRegister = SdToAsm.SdToAsmJit(context, operand.Base);
if (!maybeRegister.Present)
{
throw new Exception("could not map register");
}
switch (maybeRegister.Type)
{
case RegisterType.GpRegister:
context.Mov(target, (GpRegister)maybeRegister.Register);
break;
case RegisterType.SegRegister:
context.Mov(target, (SegRegister)maybeRegister.Register);
break;
default:
throw new Exception("unsupported register");
}
break;
case ud_type.UD_OP_MEM:
CreateLea(context, target, instruction);
break;
case ud_type.UD_OP_JIMM:
ulong immediate;
ulong truncMask = 0xffffffffffffffff >> (64 - instruction.opr_mode);
// Console.WriteLine($"opr_mode: {instruction.opr_mode}");
switch (operand.Size)
{
case 8:
immediate = (instruction.PC + (ulong)operand.LvalSByte) & truncMask;
break;
case 16:
immediate = (instruction.PC + (ulong)operand.LvalSWord) & truncMask;
break;
case 32:
immediate = (instruction.PC + (ulong)operand.LvalSDWord) & truncMask;
break;
default:
throw new Exception("invalid relative offset size.");
}
// in our emulator we are going to keep RIP in target (RAX)
context.Lea(target, Memory.QWord(target, (int)immediate));
break;
default:
throw new Exception("unsupported operand type");
}
}
public static void CreateLea(CodeContext context, GpRegister target, Instruction instruction)
{
var operand = instruction.Operands.First();
Memory memoryReference = null;
GpRegister baseRegister = null;
bool baseRipRegister = false;
MaybeRegister maybeIndexRegister = null;
if (operand.Base != ud_type.UD_NONE)
{
var maybeBaseRegister = SdToAsm.SdToAsmJit(context, operand.Base);
if (!maybeBaseRegister.Present)
{
throw new Exception($"could not map base register for: {instruction}");
}
if (maybeBaseRegister.Type != RegisterType.GpRegister)
{
if (maybeBaseRegister.Type == RegisterType.RipRegister)
{
baseRipRegister = true;
}
else
{
throw new Exception("could not map base register to GpRegister");
}
}
else
{
baseRegister = (GpRegister)maybeBaseRegister.Register;
}
}
if (operand.Index != ud_type.UD_NONE)
{
maybeIndexRegister = SdToAsm.SdToAsmJit(context, operand.Index);
if (!maybeIndexRegister.Present)
{
throw new Exception("could not map base register");
}
}
var displacement = SdToAsm.GetDisplacement(instruction, operand);
var displacementIntPtr = (IntPtr)displacement.Value;
var scale = 0;
switch (operand.Scale)
{
case 0:
case 1:
scale = 0;
break;
case 2:
scale = 1;
break;
case 4:
scale = 2;
break;
case 8:
scale = 3;
break;
}
if (baseRipRegister)
{
// in our emulator we are going to keep our RIP in target (RAX)
baseRegister = target;
if (maybeIndexRegister == null)
{
switch (operand.Size)
{
case 8:
memoryReference = Memory.Byte(baseRegister, (int)displacement.Value);
break;
case 16:
memoryReference = Memory.Word(baseRegister, (int)displacement.Value);
break;
case 32:
memoryReference = Memory.DWord(baseRegister, (int)displacement.Value);
break;
case 64:
memoryReference = Memory.QWord(baseRegister, (int)displacement.Value);
break;
case 80:
memoryReference = Memory.TWord(baseRegister, (int)displacement.Value);
break;
default:
throw new Exception("unsupported operand size");
}
}
else
{
throw new Exception("index register not supported when base register is RIP");
}
}
else
{
if (baseRegister == null && maybeIndexRegister == null)
{
switch (operand.Size)
{
case 8:
memoryReference = Memory.ByteAbs(displacementIntPtr);
break;
case 16:
memoryReference = Memory.WordAbs(displacementIntPtr);
break;
case 32:
memoryReference = Memory.DWordAbs(displacementIntPtr);
break;
case 64:
memoryReference = Memory.QWordAbs(displacementIntPtr);
break;
default:
throw new Exception("unsupported operand size");
}
}
else if (baseRegister != null && maybeIndexRegister == null)
{
switch (operand.Size)
{
case 8:
memoryReference = Memory.Byte(baseRegister, (int)displacement.Value);
break;
case 16:
memoryReference = Memory.Word(baseRegister, (int)displacement.Value);
break;
case 32:
memoryReference = Memory.DWord(baseRegister, (int)displacement.Value);
break;
case 64:
memoryReference = Memory.QWord(baseRegister, (int)displacement.Value);
break;
case 80:
memoryReference = Memory.TWord(baseRegister, (int)displacement.Value);
break;
default:
throw new Exception("unsupported operand size");
}
}
else if (baseRegister == null)
{
switch (operand.Size)
{
case 8:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.ByteAbs(displacementIntPtr,
(GpRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.ByteAbs(displacementIntPtr,
(XmmRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.ByteAbs(displacementIntPtr,
(YmmRegister)maybeIndexRegister.Register, scale);
break;
}
break;
case 16:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.WordAbs(displacementIntPtr,
(GpRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.WordAbs(displacementIntPtr,
(XmmRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.WordAbs(displacementIntPtr,
(YmmRegister)maybeIndexRegister.Register, scale);
break;
}
break;
case 32:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.DWordAbs(displacementIntPtr,
(GpRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.DWordAbs(displacementIntPtr,
(XmmRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.DWordAbs(displacementIntPtr,
(YmmRegister)maybeIndexRegister.Register, scale);
break;
}
break;
case 64:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.QWordAbs(displacementIntPtr,
(GpRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.QWordAbs(displacementIntPtr,
(XmmRegister)maybeIndexRegister.Register, scale);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.QWordAbs(displacementIntPtr,
(YmmRegister)maybeIndexRegister.Register, scale);
break;
}
break;
case 80:
throw new Exception("unsupported operand size 80");
default:
throw new Exception("unsupported operand size");
}
}
else
{
switch (operand.Size)
{
case 8:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.Byte(baseRegister,
(GpRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.Byte(baseRegister,
(XmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.Byte(baseRegister,
(YmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
}
break;
case 16:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.Word(baseRegister,
(GpRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.Word(baseRegister,
(XmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.Word(baseRegister,
(YmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
}
break;
case 32:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.DWord(baseRegister,
(GpRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.DWord(baseRegister,
(XmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.DWord(baseRegister,
(YmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
}
break;
case 64:
switch (maybeIndexRegister.Type)
{
case RegisterType.MmRegister:
throw new Exception("mmregister not supported as index by asmjit");
case RegisterType.SegRegister:
throw new Exception("segregister not supported as index by asmjit");
case RegisterType.GpRegister:
memoryReference = Memory.QWord(baseRegister,
(GpRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.XmmRegister:
memoryReference = Memory.QWord(baseRegister,
(XmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
case RegisterType.YmmRegister:
memoryReference = Memory.QWord(baseRegister,
(YmmRegister)maybeIndexRegister.Register, scale, (int)displacement.Value);
break;
}
break;
case 80:
throw new Exception("unsupported operand size 80");
default:
throw new Exception("unsupported operand size");
}
}
}
context.Lea(target, memoryReference);
}
