[FFmpeg-cvslog] r21175 - trunk/libavcodec/ac3dec.c

[reimar]

Author: reimar
Date: Wed Jan 13 00:02:07 2010
New Revision: 21175

Log:
Use MULH instead of 64x64 multiplication, around 5% overall speedup on Intel Atom.
Patch by myself and Yuriy Kaminskiy [yumkam mail ru]

Modified:
   trunk/libavcodec/ac3dec.c

Modified: trunk/libavcodec/ac3dec.c
==============================================================================
--- trunk/libavcodec/ac3dec.c	Tue Jan 12 22:36:26 2010	(r21174)
+++ trunk/libavcodec/ac3dec.c	Wed Jan 13 00:02:07 2010	(r21175)
@@ -420,10 +420,9 @@ static void calc_transform_coeffs_cpl(AC
         int band_end = bin + s->cpl_band_sizes[band];
         for (ch = 1; ch <= s->fbw_channels; ch++) {
             if (s->channel_in_cpl[ch]) {
-                int64_t cpl_coord = s->cpl_coords[ch][band];
+                int cpl_coord = s->cpl_coords[ch][band] << 5;
                 for (bin = band_start; bin < band_end; bin++) {
-                    s->fixed_coeffs[ch][bin] = ((int64_t)s->fixed_coeffs[CPL_CH][bin] *
-                                                cpl_coord) >> 23;
+                    s->fixed_coeffs[ch][bin] = MULH(s->fixed_coeffs[CPL_CH][bin] << 4, cpl_coord);
                 }
                 if (ch == 2 && s->phase_flags[band]) {
                     for (bin = band_start; bin < band_end; bin++)