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gallium/auxiliary: Use exp2(x) instead of pow(2.0, x).

This commit is contained in:
Matt Turner 2015-07-13 15:19:54 -07:00
parent b73782bf18
commit c67ce2bd3b
2 changed files with 4 additions and 4 deletions
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6
src/gallium/auxiliary/util/u_format_rgb9e5.h
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@ -115,8 +115,8 @@ static inline unsigned float3_to_rgb9e5(const float rgb[3])
exp_shared = MAX2(-RGB9E5_EXP_BIAS-1, rgb9e5_FloorLog2(maxrgb)) + 1 + RGB9E5_EXP_BIAS;
assert(exp_shared <= RGB9E5_MAX_VALID_BIASED_EXP);
assert(exp_shared >= 0);
/* This pow function could be replaced by a table. */
denom = pow(2, exp_shared - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS);
/* This exp2 function could be replaced by a table. */
denom = exp2(exp_shared - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS);
maxm = (int) floor(maxrgb / denom + 0.5);
if (maxm == MAX_RGB9E5_MANTISSA+1) {
@ -154,7 +154,7 @@ static inline void rgb9e5_to_float3(unsigned rgb, float retval[3])
v.raw = rgb;
exponent = v.field.biasedexponent - RGB9E5_EXP_BIAS - RGB9E5_MANTISSA_BITS;
scale = (float) pow(2, exponent);
scale = exp2f(exponent);
retval[0] = v.field.r * scale;
retval[1] = v.field.g * scale;

2
src/gallium/auxiliary/util/u_math.c
View File

@ -48,7 +48,7 @@ init_pow2_table(void)
{
int i;
for (i = 0; i < POW2_TABLE_SIZE; i++)
pow2_table[i] = (float) pow(2.0, (i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
pow2_table[i] = exp2f((i - POW2_TABLE_OFFSET) / POW2_TABLE_SCALE);
}