[SCM] libav/experimental: Unroll inner bidir loop in h264_loop_filter_strength_mmx2(), which gets rid of the d_idx variable and therefore allows for future optimizations. No speed difference by this commit itself.

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 2c3135f6d3faf764f5df364db00da1b2d4dcb097
Author: Ronald S. Bultje <rsbultje at gmail.com>
Date:   Wed Sep 29 13:35:24 2010 +0000

    Unroll inner bidir loop in h264_loop_filter_strength_mmx2(), which gets rid
    of the d_idx variable and therefore allows for future optimizations. No speed
    difference by this commit itself.
    
    Originally committed as revision 25253 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/x86/h264dsp_mmx.c b/libavcodec/x86/h264dsp_mmx.c
index 4df3f12..ed0dbc6 100644
--- a/libavcodec/x86/h264dsp_mmx.c
+++ b/libavcodec/x86/h264dsp_mmx.c
@@ -86,7 +86,7 @@ static av_always_inline void h264_loop_filter_strength_iteration_mmx2(int16_t bS
                         "pshufw $0x4E, %%mm2, %%mm3 \n"
                         "psubb         %%mm2, %%mm0 \n" // { ref0[b]!=ref0[bn], ref0[b]!=ref1[bn] }
                         "psubb         %%mm3, %%mm1 \n" // { ref1[b]!=ref1[bn], ref1[b]!=ref0[bn] }
-                        "1: \n"
+
                         "por           %%mm1, %%mm0 \n"
                         "movq      (%2,%0,4), %%mm1 \n"
                         "movq     8(%2,%0,4), %%mm2 \n"
@@ -103,10 +103,24 @@ static av_always_inline void h264_loop_filter_strength_iteration_mmx2(int16_t bS
                         "psubusb       %%mm5, %%mm1 \n" // abs(mv[b] - mv[bn]) >= limit
                         "psubusb       %%mm5, %%mm3 \n"
                         "packsswb      %%mm3, %%mm1 \n"
-                        "add $40, %0 \n"
-                        "cmp $40, %0 \n"
-                        "jl 1b \n"
-                        "sub $80, %0 \n"
+
+                        "por           %%mm1, %%mm0 \n"
+                        "movq   160(%2,%0,4), %%mm1 \n"
+                        "movq   168(%2,%0,4), %%mm2 \n"
+                        "movq          %%mm1, %%mm3 \n"
+                        "movq          %%mm2, %%mm4 \n"
+                        "psubw          (%2), %%mm1 \n"
+                        "psubw         8(%2), %%mm2 \n"
+                        "psubw       160(%2), %%mm3 \n"
+                        "psubw       168(%2), %%mm4 \n"
+                        "packsswb      %%mm2, %%mm1 \n"
+                        "packsswb      %%mm4, %%mm3 \n"
+                        "paddb         %%mm6, %%mm1 \n"
+                        "paddb         %%mm6, %%mm3 \n"
+                        "psubusb       %%mm5, %%mm1 \n" // abs(mv[b] - mv[bn]) >= limit
+                        "psubusb       %%mm5, %%mm3 \n"
+                        "packsswb      %%mm3, %%mm1 \n"
+
                         "pshufw $0x4E, %%mm1, %%mm1 \n"
                         "por           %%mm1, %%mm0 \n"
                         "pshufw $0x4E, %%mm0, %%mm1 \n"

-- 
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