[FFmpeg-devel] gcc 2.95.3 support plan
Wed Feb 11 18:47:06 CET 2009
On 2/11/09, Loren Merritt <lorenm at u.washington.edu> wrote:
> On Wed, 11 Feb 2009, Ivan Kalvachev wrote:
>> It is absolutely safe to remove that function as it have never worked
>> in the first place. At the moment it is used when MMX_EXT is not
>> present but 3DNow is. That condition is true only on K6-2/3 processors
>> and they for sure do not have cmov instruction. (Table.9 AMD Processor
>> Recognition 20734.pdf).
> No, it is used when both MMXEXT and 3DNOW are present, i.e. k7, k8, and k10.
> If y'all want I can add cmov detection to cpuid, and change my function to
> CMOV && 3DNOW. But it should be the same result on all existent cpus.
So on AMD the plain asm cmov function is faster than mmxext.
Can you show benchmarks?
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