Messages in this thread | | | Date | Fri, 6 Aug 2004 09:43:52 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH] Re-implemented i586 asm AES (updated) |
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On Fri, 6 Aug 2004, Andi Kleen wrote: > > You could use .altinstructions to patch a jump in at runtime > based on CPU capabilities. Assuming MMX is really faster of course.
I seriously doubt that the MMX code could be faster.
The only MMX code in the original was saving some integer contents to a scratch MMX register rather than saving to memory. There's _no_ way that is faster, especially since in the kernel it would require us much extra work to first check that the FP context is safed. Even _without_ the extra work I simply cannot imagine that a "movd reg,mmx" is faster than a plain "movl reg,stackslot".
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