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authorBrian Paul <brian.paul@tungstengraphics.com>2008-08-22 15:14:36 -0600
committerBrian Paul <brian.paul@tungstengraphics.com>2008-08-22 15:14:36 -0600
commit47d4b958cfaac080a97bf0ba21d78b3ce37b62a9 (patch)
tree65e4e0d17fd6dc6d39d1a8092de7616742a2af22
parent9e2b867b3f2e9afc9e9f9178788ae07f6be1f3c0 (diff)
mesa: glsl: implement exp() functions in terms of EXP asm instruction, not pow
-rw-r--r--src/mesa/shader/slang/library/slang_common_builtin.gc29
1 files changed, 15 insertions, 14 deletions
diff --git a/src/mesa/shader/slang/library/slang_common_builtin.gc b/src/mesa/shader/slang/library/slang_common_builtin.gc
index e908e6c940..561e94f6ba 100644
--- a/src/mesa/shader/slang/library/slang_common_builtin.gc
+++ b/src/mesa/shader/slang/library/slang_common_builtin.gc
@@ -473,32 +473,33 @@ vec4 pow(const vec4 a, const vec4 b)
float exp(const float a)
{
- const float e = 2.71828;
- __asm float_power __retVal, e, a;
+ // NOTE: log2(e) = 1.44269502
+ float t = a * 1.44269502;
+ __asm float_exp2 __retVal, t;
}
vec2 exp(const vec2 a)
{
- const float e = 2.71828;
- __asm float_power __retVal.x, e, a.x;
- __asm float_power __retVal.y, e, a.y;
+ vec2 t = a * 1.44269502;
+ __asm float_exp2 __retVal.x, t.x;
+ __asm float_exp2 __retVal.y, t.y;
}
vec3 exp(const vec3 a)
{
- const float e = 2.71828;
- __asm float_power __retVal.x, e, a.x;
- __asm float_power __retVal.y, e, a.y;
- __asm float_power __retVal.z, e, a.z;
+ vec3 t = a * 1.44269502;
+ __asm float_exp2 __retVal.x, t.x;
+ __asm float_exp2 __retVal.y, t.y;
+ __asm float_exp2 __retVal.z, t.z;
}
vec4 exp(const vec4 a)
{
- const float e = 2.71828;
- __asm float_power __retVal.x, e, a.x;
- __asm float_power __retVal.y, e, a.y;
- __asm float_power __retVal.z, e, a.z;
- __asm float_power __retVal.w, e, a.w;
+ vec4 t = a * 1.44269502;
+ __asm float_exp2 __retVal.x, t.x;
+ __asm float_exp2 __retVal.y, t.y;
+ __asm float_exp2 __retVal.z, t.z;
+ __asm float_exp2 __retVal.w, t.w;
}