Andreas Rheinhardt: > Improves performance by about 30%. > > Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> > --- > [1] is a patch that would also move the bitreverse into the LUT; > it didn't make a difference in the benchmarks here, but if it is > an improvement for someone else, it could still be applied. > [1]: > https://github.com/mkver/FFmpeg/commit/d4fdac5335d2ccf29f7b55fe3147edf388bb7efa > libavcodec/xbmdec.c | 27 ++++++++++++++++----------- > 1 file changed, 16 insertions(+), 11 deletions(-) > > diff --git a/libavcodec/xbmdec.c b/libavcodec/xbmdec.c > index ecfc957a3f..2d84327e02 100644 > --- a/libavcodec/xbmdec.c > +++ b/libavcodec/xbmdec.c > @@ -28,17 +28,22 @@ > > static int get_nibble(uint8_t x) > { > - int ret = 255; > - > - if (x <= '9') { > - if (x >= '0') > - ret = x - '0'; > - } else if (x >= 'a') { > - if (x <= 'f') > - ret = x - ('a' - 10); > - } else if (x >= 'A' && x <= 'F') > - ret = x - ('A' - 10); > - return ret; > +#define TIMES256(idx) \ > +TIMES64(4 * (idx)) TIMES64(4 * (idx) + 1) TIMES64(4 * (idx) + 2) TIMES64(4 * > (idx) + 3) > +#define TIMES64(idx) \ > +TIMES16(4 * (idx)) TIMES16(4 * (idx) + 1) TIMES16(4 * (idx) + 2) TIMES16(4 * > (idx) + 3) > +#define TIMES16(idx) \ > +TIMES4(4 * (idx)) TIMES4(4 * (idx) + 1) TIMES4(4 * (idx) + 2) TIMES4(4 * > (idx) + 3) > +#define TIMES4(idx) \ > +ENTRY(4 * (idx)) ENTRY(4 * (idx) + 1) ENTRY(4 * (idx) + 2) ENTRY(4 * (idx) + > 3) > +#define ENTRY(x) [x] = ((x) >= 'a' && (x) <= 'f') ? (x) - ('a' - 10) : \ > + ((x) >= 'A' && (x) <= 'F') ? (x) - ('A' - 10) : \ > + ((x) >= '0' && (x) <= '9') ? (x) - '0' : 255, > + > + static const uint8_t lut[] = { > + TIMES256(0) > + }; > + return lut[x]; > } > > static int parse_str_int(const uint8_t *p, const uint8_t *end, const uint8_t > *key)
Will apply. - Andreas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
