public object TryLookup(CodeContext mode,
ImmutableLegacyPrefixList legacyPrefixes, Xex xex, byte opcode,
out bool hasModRM, out int immediateSizeInBytes)
{
if (xex.OpcodeMap == OpcodeMap.Default && opcode == 0x90)
{
// NOP
hasModRM = false;
immediateSizeInBytes = 0;
return found;
}
else if (xex.OpcodeMap == OpcodeMap.Escape0F && opcode == 0x1F)
{
// 3+ byte nop form
hasModRM = true;
immediateSizeInBytes = 0;
return found;
}
else if (xex.OpcodeMap == OpcodeMap.Default && (opcode & 0xF8) == 0xB0)
{
// MOV x8, imm8
hasModRM = false;
immediateSizeInBytes = 1;
return found;
}
else if (xex.OpcodeMap == OpcodeMap.Default && (opcode & 0xF8) == 0xB8)
{
// Mov r(16|32|64), imm(16|32|64)
OperandSize operandSize;
if (mode == CodeContext.SixtyFourBit)
operandSize = xex.OperandSize64 ? OperandSize.Qword : OperandSize.Dword;
else
operandSize = mode.GetDefaultOperandSize().OverrideWordDword(
legacyPrefixes.HasOperandSizeOverride);
hasModRM = false;
immediateSizeInBytes = operandSize.InBytes();
return found;
}
else if (xex.OpcodeMap == OpcodeMap.Escape0F
&& (xex.SimdPrefix ?? legacyPrefixes.GetSimdPrefix(xex.OpcodeMap)) == SimdPrefix._66
&& opcode == 0x58)
{
hasModRM = true;
immediateSizeInBytes = 0;
return found;
}
else
{
hasModRM = false;
immediateSizeInBytes = 0;
return null;
}
}
