[FFmpeg-devel] [PATCH] Port extra x264 CPU detection code
Wed Jan 7 17:46:59 CET 2009
This patch adds two features from x264:
1. Completely disable SSE2 on Core 1 and Pentium-M CPUs (detected
using family/model/stepping). These CPUs are so slow at SSE2 that it
is almost universally slower than MMX. Even with x264's enormous
library of asm functions, only a single one turned out to be faster on
SSE2 than MMX, and only by a few clocks, so we simply pretend that
these CPUs do not have SSE2 at all.
Yes, these CPUs have much slower SSE2 than even the Athlon 64.
2. Replace 3DNOW with SSE2_IS_SLOW when used for that purpose. This
is because the Phenom has 3DNOW, but it isn't slow at SSE2.
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