Hi Paolo,
On 8/17/17 1:37 PM, Brijesh Singh wrote: > On 08/17/2017 11:45 AM, Paolo Bonzini wrote: >> On 15/08/2017 19:00, Brijesh Singh wrote: >>> >>> The following features bits have been added/removed compare to >>> Opteron_G5 >>> >>> Added: monitor, movbe, rdrand, mmxext, ffxsr, rdtscp, cr8legacy, osvw, >>> fsgsbase, bmi1, avx2, smep, bmi2, rdseed, adx, smap, >>> clfshopt, sha >>> xsaveopt, xsavec, xgetbv1, arat >>> >>> Removed: xop, fma4, tbm >> >> Interesting, why were these removed? >> > > I don't know exact reason why these were removed - I am going with > whatever is > listed as supported feature bit in PPR [1], but I will ask around and > let you > know. I believe some of these instruction are superseded with newer > instructions > (e.g fma4->fma) > > [1] > http://support.amd.com/TechDocs/54945_PPR_Family_17h_Models_00h-0Fh.pdf > > I checked with CPU team, it seems those instruction sets were never really used, I believe AMD came up with them but they were superseded by SSE4/AVX extensions. -Brijesh
