On Wed, Oct 24, 2012 at 1:06 PM, Uros Bizjak <ubiz...@gmail.com> wrote: >>> Please take a look at the attached patch. >>> >>> I changed the asm-pattern implementation according to your recomendation. >>> Changed the name of feature option from -mfxsave to -mfxsr, as it is in >>> Intel SDM. Corrected the arguments name in the headers. >>> >>> Bootstrap passes >> >> I think you should add bit_FXSR. Also you should turn off XSAVE if OSXSAVE >> is >> off, according to Intel SDM. > > There is no need for additional bit_FXSR. We already have plenty of > "misnamed" bits in cpuid.h and we can live with them just fine. > >> I think we should check OSFXSR bit for OS SSE support in driver-i386.c before >> enabling SSE and FXSR, similar to OSXSAVE bit. If we do that, we should >> enable >> FXSR when enabling SSE. > > This was already discussed, and the conclusion was that SSE and FXSR > are orhogonal, so we don't need to tie them together.
Oh, I see. Actually, we have to _disable_ SSE related features in driver-i386 when FXSR cpuid bit is not set. But I think this is not necessary, since probably all processors with SSE bit set also have FXSR bit set. Opposite is not necessary true. Uros.
