[FFmpeg-cvslog] r23097 - trunk/libavcodec/mpegaudiodec.c
michael
subversion
Tue May 11 23:10:55 CEST 2010
Author: michael
Date: Tue May 11 23:10:55 2010
New Revision: 23097
Log:
Optimize decoding high freqs.
this is 10-20cpu cycles faster on duron (whole is about 50-60 cpu cylses)
I wonder why gcc isnt doing this on its own ...
Modified:
trunk/libavcodec/mpegaudiodec.c
Modified: trunk/libavcodec/mpegaudiodec.c
==============================================================================
--- trunk/libavcodec/mpegaudiodec.c Tue May 11 22:33:48 2010 (r23096)
+++ trunk/libavcodec/mpegaudiodec.c Tue May 11 23:10:55 2010 (r23097)
@@ -1535,14 +1535,22 @@ static int huffman_decode(MPADecodeConte
g->sb_hybrid[s_index+3]= 0;
while(code){
static const int idxtab[16]={3,3,2,2,1,1,1,1,0,0,0,0,0,0,0,0};
- INTFLOAT v;
+ int v;
int pos= s_index+idxtab[code];
code ^= 8>>idxtab[code];
- v = RENAME(exp_table)[ exponents[pos] ];
-// v = RENAME(exp_table)[ (exponents[pos]&3) ] >> FFMIN(0 - (exponents[pos]>>2), 31);
- if(get_bits1(&s->gb)) //FIXME try to flip the sign bit in int32_t, same above
+/* Following is a optimized code for
+ INTFLOAT v = RENAME(exp_table)[ exponents[pos] ];
+ if(get_bits1(&s->gb))
v = -v;
g->sb_hybrid[pos] = v;
+*/
+#if CONFIG_FLOAT
+ v = AV_RN32A(RENAME(exp_table)+exponents[pos]) ^ (get_bits1(&s->gb)<<31);
+ AV_WN32A(g->sb_hybrid+pos, v);
+#else
+ v= -get_bits1(&s->gb);
+ g->sb_hybrid[pos] = (RENAME(exp_table)[ exponents[pos] ] ^ v) - v;
+#endif
}
s_index+=4;
}
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