Hi,

Okay, let say next:
1) it depends on compiler you used. It may truncate high byte, other one stops and prints a warning, another may even use MAX_UCHAR value (255)... The idea is that you should write program with safe and clean way.
2) Anyway it is just the constant value which is calculated at compilation time and so does not have an effect on result code. So it does not need for "optimization" related on used compiler.

Regards,
Oleg