From: Michal Krol <michal@tungstengraphics.com>
Date: Wed, 12 Nov 2008 18:02:41 +0000 (+0100)
Subject: util: Optimise log2().
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=0d8637451b7bf1aac164dba6d269d1a665160ea3;p=mesa.git

util: Optimise log2().
---

diff --git a/src/gallium/auxiliary/util/u_math.h b/src/gallium/auxiliary/util/u_math.h
index c7bbebc4286..aee69ab7bae 100644
--- a/src/gallium/auxiliary/util/u_math.h
+++ b/src/gallium/auxiliary/util/u_math.h
@@ -163,7 +163,8 @@ static INLINE float logf( float f )
 
 static INLINE double log2( double x )
 {
-   return log( x ) / log( 2.0 );
+   const double invln2 = 1.442695041;
+   return log( x ) * invln2;
 }
 
 #else