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Convert VP8LFastSLog2 to fixed point

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Speedups: 1% with '-lossless', 2% with '-lossless -q 100 -m6'

Change-Id: I1d79ea8e3e9e4bac7bcea4d7cbcc1bd56273988e
This commit is contained in:
Vincent Rabaud
2024-07-09 15:44:18 +02:00
parent 66408c2c7c
commit fb444b692b
7 changed files with 128 additions and 260 deletions
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11
src/dsp/lossless_common.h
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@ -82,15 +82,12 @@ static WEBP_INLINE int VP8LNearLosslessBits(int near_lossless_quality) {
#define LOG_2_RECIPROCAL 1.44269504088896338700465094007086
// LOG_2_RECIPROCAL * (1 << LOG_2_PRECISION_BITS)
#define LOG_2_RECIPROCAL_FIXED_DOUBLE 12102203.161561485379934310913085937500
#define LOG_2_RECIPROCAL_FIXED 12102203
#define LOG_2_RECIPROCAL_FIXED ((uint64_t)12102203)
#define LOG_LOOKUP_IDX_MAX 256
extern const uint32_t kLog2Table[LOG_LOOKUP_IDX_MAX];
extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX];
// TODO(vrabaud) remove this table once VP8LFastSLog2 is switched to fixed
// point.
extern const float kLog2fTable[LOG_LOOKUP_IDX_MAX];
extern const uint64_t kSLog2Table[LOG_LOOKUP_IDX_MAX];
typedef uint32_t (*VP8LFastLog2SlowFunc)(uint32_t v);
typedef float (*VP8LFastSLog2SlowFunc)(uint32_t v);
typedef uint64_t (*VP8LFastSLog2SlowFunc)(uint32_t v);
extern VP8LFastLog2SlowFunc VP8LFastLog2Slow;
extern VP8LFastSLog2SlowFunc VP8LFastSLog2Slow;
@ -99,7 +96,7 @@ static WEBP_INLINE uint32_t VP8LFastLog2(uint32_t v) {
return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v);
}
// Fast calculation of v * log2(v) for integer input.
static WEBP_INLINE float VP8LFastSLog2(uint32_t v) {
static WEBP_INLINE uint64_t VP8LFastSLog2(uint32_t v) {
return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v);
}