diff options
Diffstat (limited to 'libavcodec/lagarithrac.h')
| -rw-r--r-- | libavcodec/lagarithrac.h | 15 |
1 files changed, 3 insertions, 12 deletions
diff --git a/libavcodec/lagarithrac.h b/libavcodec/lagarithrac.h index 7d60d56c2f..dfdfea0db3 100644 --- a/libavcodec/lagarithrac.h +++ b/libavcodec/lagarithrac.h @@ -72,9 +72,8 @@ static inline void lag_rac_refill(lag_rac *l) */ static inline uint8_t lag_get_rac(lag_rac *l) { - unsigned range_scaled, low_scaled, div; + unsigned range_scaled, low_scaled; int val; - uint8_t shift; lag_rac_refill(l); @@ -85,16 +84,8 @@ static inline uint8_t lag_get_rac(lag_rac *l) if (l->low < range_scaled * l->prob[1]) { val = 0; } else { - /* FIXME __builtin_clz is ~20% faster here, but not allowed in generic code. */ - shift = 30 - av_log2(range_scaled); - div = ((range_scaled << shift) + (1 << 23) - 1) >> 23; - /* low>>24 ensures that any cases too big for exact FASTDIV are - * under- rather than over-estimated - */ - low_scaled = FASTDIV(l->low - (l->low >> 24), div); - shift -= l->hash_shift; - low_scaled = (low_scaled >> (32 - shift)); - /* low_scaled is now a lower bound of low/range_scaled */ + low_scaled = l->low / (range_scaled<<(l->hash_shift)); + val = l->range_hash[low_scaled]; while (l->low >= range_scaled * l->prob[val + 1]) val++; |