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author | Peter Cordes <peter@cordes.ca> | 2015-01-30 00:20:27 +0300 |
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committer | Michael Niedermayer <michaelni@gmx.at> | 2015-03-04 23:58:53 +0300 |
commit | 9e5687adf20aff27cd4922d0f68f54c9622418bd (patch) | |
tree | 2c9ee22abb6200397dc834cc12613e4875fb40f4 /libavutil/x86/pixelutils_init.c | |
parent | 4da3a14f3ca4428ac4606b971d990202b7dce1a9 (diff) |
pixelutils: Comment on (lack of) sad_8x8_sse2
Signed-off-by: Peter Cordes <peter@cordes.ca>
Diffstat (limited to 'libavutil/x86/pixelutils_init.c')
-rw-r--r-- | libavutil/x86/pixelutils_init.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/libavutil/x86/pixelutils_init.c b/libavutil/x86/pixelutils_init.c index d60051067a..c24a533aea 100644 --- a/libavutil/x86/pixelutils_init.c +++ b/libavutil/x86/pixelutils_init.c @@ -43,6 +43,12 @@ void ff_pixelutils_sad_init_x86(av_pixelutils_sad_fn *sad, int aligned) sad[2] = ff_pixelutils_sad_8x8_mmx; } + // The best way to use SSE2 would be to do 2 SADs in parallel, + // but we'd have to modify the pixelutils API to return SIMD functions. + + // It's probably not faster to shuffle data around + // to get two lines of 8 pixels into a single 16byte register, + // so just use the MMX 8x8 version even when SSE2 is available. if (EXTERNAL_MMXEXT(cpu_flags)) { sad[2] = ff_pixelutils_sad_8x8_mmxext; sad[3] = ff_pixelutils_sad_16x16_mmxext; |