5 Dec
2003
5 Dec
'03
2:48 p.m.
On Thu, Dec 04, 2003 at 11:22:08PM -0700, Eric W. Biederman wrote:
I would think it would hurt since x86 lets you use those little sub-registers (puddle arithmetic), so using bigger registers reduces the number of registers available.
Yes, being able to use this from romcc would severely lower register pressure I assume. Neither romcc nor the code compiled with it takes care of this at the moment though.
I tried this at one point. And the problem is that there is not a instruction sequence to move to/from the byte registers from a normal 32bit register.
Hmm, there's movzx and movsx for moving to 32 bit, but from 32 to 8 is worse for esi, edi and ebp. 32->16 works fine of course.
I could be missing something though. :)
//Peter