On Fri, Sep 28, 2018 at 5:33 AM Marc Joliet <mar...@gmx.de> wrote: > > Am Freitag, 28. September 2018, 06:04:29 CEST schrieb Walter Dnes: > > mmxext does not have its own flag in /proc/cpuinfo. > > ??? > > % cat /proc/cpuinfo > [...] > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge > mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt > rdtscp lm 3dnowext 3dnow rep_good nopl cpuid extd_apicid pni cx16 lahf_lm > cmp_legacy svm extapic cr8_legacy 3dnowprefetch vmmcall > > ^^^ ^^^^^^ > (I hope the formatting doesn't get messed up, the point is that my > /proc/cpuinfo *does* show mmxext.)
That cpuid flag only appears on AMD processors. It is never set for Intel processors. cpuid2cpuflags makes a special exception for this case. https://github.com/mgorny/cpuid2cpuflags/blob/master/src/x86.c#L71
