math.integers: faster fixnum-log2.

2013-02-27 16:01:34 -08:00 · 2013-02-27 16:01:34 -08:00 · 7ba77673a8
parent 927414c6c5
commit 7ba77673a8
1 changed files with 3 additions and 1 deletions
--- a/core/math/integers/integers.factor
+++ b/core/math/integers/integers.factor
@ -57,7 +57,9 @@ M: fixnum bitnot fixnum-bitnot ; inline
 M: fixnum bit? fixnum-bit? ; inline

 : fixnum-log2 ( x -- n )
-    0 swap [ dup 1 eq? ] [ [ 1 + ] [ 2/ ] bi* ] until drop ; inline
+    0 swap [ dup 1 eq? ] [
+        [ 1 fixnum+fast ] [ 2/ ] bi*
+    ] until drop ; inline

 M: fixnum (log2) fixnum-log2 ; inline