Hi,
On Fri, Jul 17, 2026 at 4:21 AM Aleksander Shveikin via ffmpeg-devel
<[email protected]> wrote:
>
> This patch converts ff_vp8_idct_dc_add4uv_mmx to ff_vp8_idct_dc_add4uv_sse2.
>
> Here are the checkasm benchmark results:
>
> vp8_idct_dc_add4uv_c: 359.9
> vp8_idct_dc_add4uv_mmx: 59.7 ( 6.02x)
> vp8_idct_dc_add4uv_sse2: 21.1 (17.06x)
>
> Signed-off-by: Aleksander Shveikin <[email protected]>
> ---
> libavcodec/x86/vp8dsp.asm | 22 ++++++++++------------
> libavcodec/x86/vp8dsp_init.c | 7 ++-----
> 2 files changed, 12 insertions(+), 17 deletions(-)
>
> diff --git a/libavcodec/x86/vp8dsp.asm b/libavcodec/x86/vp8dsp.asm
> index 22356f687b..d14843e325 100644
> --- a/libavcodec/x86/vp8dsp.asm
> +++ b/libavcodec/x86/vp8dsp.asm
> @@ -937,8 +937,8 @@ cglobal vp8_idct_dc_add4y, 3, 3, 6, dst, block, stride
> ; void ff_vp8_idct_dc_add4uv_<opt>(uint8_t *dst, int16_t block[4][16],
> ptrdiff_t stride);
>
> ;-----------------------------------------------------------------------------
>
> -INIT_MMX mmx
> -cglobal vp8_idct_dc_add4uv, 3, 3, 0, dst, block, stride
> +INIT_XMM sse2
> +cglobal vp8_idct_dc_add4uv, 3, 3, 8, dst, block, stride
If possible, limit the use of xmm registers to m0 to m5, so that the
callee doesn't have to save any xmm under Windows.
> ; load data
> movd m0, [blockq+32*0] ; A
> movd m1, [blockq+32*2] ; C
> @@ -957,22 +957,20 @@ cglobal vp8_idct_dc_add4uv, 3, 3, 0, dst, block, stride
> psubw m6, m0
> packuswb m0, m0
> packuswb m6, m6
> - punpcklbw m0, m0 ; AABBCCDD
> - punpcklbw m6, m6 ; AABBCCDD
> - movq m1, m0
> - movq m7, m6
> - punpcklbw m0, m0 ; AAAABBBB
> - punpckhbw m1, m1 ; CCCCDDDD
> - punpcklbw m6, m6 ; AAAABBBB
> - punpckhbw m7, m7 ; CCCCDDDD
> + punpcklbw m0, m0
> + punpcklbw m6, m6
> + punpcklbw m0, m0
> + punpcklbw m6, m6
> + movhlps m1, m0
> + movhlps m7, m6
>
> ; add DC
> DEFINE_ARGS dst1, dst2, stride
> lea dst2q, [dst1q+strideq*2]
> - ADD_DC m0, m6, 0, mova
> + ADD_DC m0, m6, 0, movh
> lea dst1q, [dst1q+strideq*4]
> lea dst2q, [dst2q+strideq*4]
> - ADD_DC m1, m7, 0, mova
> + ADD_DC m1, m7, 0, movh
> RET
>
>
> ;-----------------------------------------------------------------------------
> diff --git a/libavcodec/x86/vp8dsp_init.c b/libavcodec/x86/vp8dsp_init.c
> index 828b038cdf..ded136d186 100644
> --- a/libavcodec/x86/vp8dsp_init.c
> +++ b/libavcodec/x86/vp8dsp_init.c
> @@ -169,7 +169,7 @@ void ff_vp8_idct_dc_add_sse4(uint8_t *dst, int16_t
> block[16],
> ptrdiff_t stride);
> void ff_vp8_idct_dc_add4y_sse2(uint8_t *dst, int16_t block[4][16],
> ptrdiff_t stride);
> -void ff_vp8_idct_dc_add4uv_mmx(uint8_t *dst, int16_t block[2][16],
> +void ff_vp8_idct_dc_add4uv_sse2(uint8_t *dst, int16_t block[4][16],
> ptrdiff_t stride);
> void ff_vp8_luma_dc_wht_sse(int16_t block[4][4][16], int16_t dc[16]);
> void ff_vp8_idct_add_sse(uint8_t *dst, int16_t block[16], ptrdiff_t stride);
> @@ -272,10 +272,6 @@ av_cold void ff_vp8dsp_init_x86(VP8DSPContext *c)
> {
> int cpu_flags = av_get_cpu_flags();
>
> - if (EXTERNAL_MMX(cpu_flags)) {
> - c->vp8_idct_dc_add4uv = ff_vp8_idct_dc_add4uv_mmx;
> - }
> -
> if (EXTERNAL_SSE(cpu_flags)) {
> c->vp8_idct_add = ff_vp8_idct_add_sse;
> c->vp8_luma_dc_wht = ff_vp8_luma_dc_wht_sse;
> @@ -294,6 +290,7 @@ av_cold void ff_vp8dsp_init_x86(VP8DSPContext *c)
> if (EXTERNAL_SSE2(cpu_flags)) {
> c->vp8_idct_dc_add = ff_vp8_idct_dc_add_sse2;
> c->vp8_idct_dc_add4y = ff_vp8_idct_dc_add4y_sse2;
> + c->vp8_idct_dc_add4uv = ff_vp8_idct_dc_add4uv_sse2;
>
> c->vp8_h_loop_filter_simple = ff_vp8_h_loop_filter_simple_sse2;
>
> --
> 2.43.0
>
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--
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While truth is beauty.
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