On Tue, Jan 28, 2003 at 02:39:06AM +0900, GOTO Masanori wrote: > At Mon, 27 Jan 2003 11:39:43 -0500 (EST), > Alan Cox wrote: > > > >>>>>GCC 3.2 still uses CMOVE instructions on -march=i686. > > > >>>>> > > > >>>>>On the other hand: > > > >>>>> {"c3", PROCESSOR_I486, PTA_MMX | PTA_3DNOW}, > > > >>>>>GCC disagrees with you that the C3 is an i686. > > > > gcc uses i486 scheduling because that gives best performance > > > > The situation is as follows > > > > gcc "i686" definition is wrong. The gcc people wont fix it because the 686 > > definition without cmov is mostly useless anyway. > > Thanks for your explanation. Hmm. "cmov" is really key instruction... > > I think it may be needed that we add -mcpu=c3 for gcc, which generates > i686 without cmov instruction.
It's already there in development GCC versions. I think Andi Kleen did it. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer