private bool TryDecodeOperand(PrimitiveType width, out MachineOperand op)
{
op = null;
byte b;
byte bSpecifier;
ushort w;
uint dw;
if (!rdr.TryReadByte(out bSpecifier))
{
return(false);
}
var reg = arch.GetRegister(bSpecifier & 0xF);
switch (bSpecifier >> 4)
{
case 0: // Literal mode
case 1:
case 2:
case 3:
op = LiteralOperand(width, bSpecifier);
break;
case 4: // Index mode
op = IndexOperand(width, reg);
break;
case 5: // Register mode
op = new RegisterOperand(reg);
break;
case 6: // Register deferred
op = new MemoryOperand(width)
{
Base = reg
};
break;
case 7: // Autodecrement mode
op = new MemoryOperand(width)
{
Base = reg,
AutoDecrement = true,
};
break;
case 8: // Autoincrement mode
if (reg.Number == 0x0F)
{
op = ImmediateOperand(width);
}
else
{
op = new MemoryOperand(width)
{
Base = reg,
AutoIncrement = true,
};
}
break;
case 9: // Deferred Autoincrement mode
op = new MemoryOperand(width)
{
Base = reg,
AutoIncrement = true,
Deferred = true,
};
break;
case 0xA: // Displacement mode
case 0xD:
if (!rdr.TryReadByte(out b))
{
return(false);
}
op = DisplacementOperand(width, reg, Constant.SByte((sbyte)b), bSpecifier);
break;
case 0xB:
case 0xE:
if (!rdr.TryReadUInt16(out w))
{
return(false);
}
op = DisplacementOperand(width, reg, Constant.Int16((short)w), bSpecifier);
break;
case 0xC:
case 0xF:
if (!rdr.TryReadUInt32(out dw))
{
return(false);
}
op = DisplacementOperand(width, reg, Constant.Word32(dw), bSpecifier);
break;
default:
throw new InvalidCastException("Impossiburu!");
}
return(true);
}
private bool TryDecodeOperand(PrimitiveType width, out MachineOperand op)
{
op = null;
byte b;
byte bSpecifier;
ushort w;
uint dw;
if (!rdr.TryReadByte(out bSpecifier))
{
return(false);
}
var reg = arch.GetRegister(bSpecifier & 0xF);
switch (bSpecifier >> 4)
{
case 0: // Literal mode
case 1:
case 2:
case 3:
op = LiteralOperand(width, bSpecifier);
break;
case 5: // Register mode
op = new RegisterOperand(reg);
break;
case 7: // Autodecrement mode
op = new MemoryOperand(width)
{
Base = reg,
AutoDecrement = true,
};
break;
case 8: // Autoincrement mode
op = new MemoryOperand(width)
{
Base = reg,
AutoIncrement = true,
};
break;
case 9: // Deferred Autoincrement mode
op = new MemoryOperand(width)
{
Base = reg,
AutoIncrement = true,
Deferred = true,
};
break;
case 10: // Displacement mode
case 11:
if (!rdr.TryReadByte(out b))
{
return(false);
}
op = DisplacementOperand(width, reg, Constant.SByte((sbyte)b), bSpecifier);
break;
case 12:
case 13:
if (!rdr.TryReadUInt16(out w))
{
return(false);
}
op = DisplacementOperand(width, reg, Constant.Int16((short)w), bSpecifier);
break;
case 14:
case 15:
if (!rdr.TryReadUInt32(out dw))
{
return(false);
}
op = DisplacementOperand(width, reg, Constant.Word32(dw), bSpecifier);
break;
default:
throw new NotImplementedException(
string.Format(
"Unimplemented addressing mode {0:X2}", (bSpecifier >> 4)));
}
return(true);
}