More efficient implementation of frandom() in stdlib

2011-08-03 14:28:06 +01:00
parent 7d7dd2b204
commit a2996ed5d9
3 changed files with 47 additions and 1 deletions
--- a/stdlib.ispc
+++ b/stdlib.ispc
@@ -2624,7 +2624,9 @@ static inline unsigned int random(reference RNGState state)

 static inline float frandom(reference RNGState state)
 {
-    return ((int)(random(state) & ((1<<24)-1))) / (float)(1 << 24);
+    unsigned int irand = random(state);
+    irand &= (1<<23)-1;
+    return floatbits(0x3F800000 | irand)-1.0f;
 }

 static inline uniform unsigned int __seed4(reference RNGState state,