Richard Henderson wrote: > On 01/14/2010 08:10 AM, Aurelien Jarno wrote: > >With the above change, rex can be > 0xff. Not sure it's not a good idea > >to not have an explicit cast when calling tcg_out8(), even if it > >technically works.
> >What's the reason for removing the '& 0xff' part? tcg_out8() takes an > >uint8_t. > > Yes, and the uint8_t truncates the value just fine. Is there any > particular reason you want to clutter the code with a duplicate > truncation? It might have been reasonable if the function name didn't > quite clearly indicate that a single byte was going to be output... The & 0xff makes it clear that rex > 0xff is intentional; that you have thought about it. Otherwise it looks like rex > 0xff might be unintentional. Anyone can check the code isn't mistaken, but it's better if it doesn't *look* like a mistake. After all, there have been mistakes in this sort of code elsewhere many times. In this sense, I think it's not cluttering; it's removing excessive subtlety. I would hope that GCC optimises the & 0xff away. -- Jamie
