diff options
Diffstat (limited to 'src/gallium/auxiliary/util')
| -rw-r--r-- | src/gallium/auxiliary/util/u_math.c | 6 | ||||
| -rw-r--r-- | src/gallium/auxiliary/util/u_math.h | 8 |
2 files changed, 8 insertions, 6 deletions
diff --git a/src/gallium/auxiliary/util/u_math.c b/src/gallium/auxiliary/util/u_math.c index 9c5f616ceb..2811475fa0 100644 --- a/src/gallium/auxiliary/util/u_math.c +++ b/src/gallium/auxiliary/util/u_math.c @@ -30,7 +30,7 @@ #include "util/u_math.h" -/** 2^x, for x in [-1.0, 1.0] */ +/** 2^x, for x in [-1.0, 1.0) */ float pow2_table[POW2_TABLE_SIZE]; @@ -43,7 +43,7 @@ init_pow2_table(void) } -/** log2(x), for x in [1.0, 2.0] */ +/** log2(x), for x in [1.0, 2.0) */ float log2_table[LOG2_TABLE_SIZE]; @@ -52,7 +52,7 @@ init_log2_table(void) { unsigned i; for (i = 0; i < LOG2_TABLE_SIZE; i++) - log2_table[i] = (float) log2(1.0 + i * (1.0 / LOG2_TABLE_SIZE)); + log2_table[i] = (float) log2(1.0 + i * (1.0 / LOG2_TABLE_SCALE)); } diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h index fdaec8df82..653d79ccd5 100644 --- a/src/gallium/auxiliary/util/u_math.h +++ b/src/gallium/auxiliary/util/u_math.h @@ -246,8 +246,9 @@ util_fast_exp(float x) } -#define LOG2_TABLE_SIZE_LOG2 8 -#define LOG2_TABLE_SIZE (1 << LOG2_TABLE_SIZE_LOG2) +#define LOG2_TABLE_SIZE_LOG2 16 +#define LOG2_TABLE_SCALE (1 << LOG2_TABLE_SIZE_LOG2) +#define LOG2_TABLE_SIZE (LOG2_TABLE_SCALE + 1) extern float log2_table[LOG2_TABLE_SIZE]; @@ -258,7 +259,8 @@ util_fast_log2(float x) float epart, mpart; num.f = x; epart = (float)(((num.i & 0x7f800000) >> 23) - 127); - mpart = log2_table[(num.i & 0x007fffff) >> (23 - LOG2_TABLE_SIZE_LOG2)]; + /* mpart = log2_table[mantissa*LOG2_TABLE_SCALE + 0.5] */ + mpart = log2_table[((num.i & 0x007fffff) + (1 << (22 - LOG2_TABLE_SIZE_LOG2))) >> (23 - LOG2_TABLE_SIZE_LOG2)]; return epart + mpart; } |