prediction (plus some with different rounding for svq3/rv40). Speedup (for
SSSE3) about ~6-fold, 3.6% faster overall with cathedral sample.
Originally committed as revision 25361 to svn://svn.ffmpeg.org/ffmpeg/trunk
into its own file, it doesn't belong in h264dsp_mmx.c (much less so in
dsputil_mmx.c).
Originally committed as revision 24990 to svn://svn.ffmpeg.org/ffmpeg/trunk