Fix sign error and mask size in fix:bitcount16.

diff --git a/src/runtime/random.scm b/src/runtime/random.scm
index 7a4e30cc002a763c952470497041dc47e5f120ab..14be33598d03aaa1f16887066bc74f03530ea59c 100644 (file)
--- a/src/runtime/random.scm
+++ b/src/runtime/random.scm
@@ -353,12 +353,12 @@ USA.
    (define (fix:bitcount16 x)
      (let* ((x1 (fix:- x (fix:and (fix:lsh x -1) #x5555)))
            (x2 (fix:+ (fix:and (fix:lsh x1 -2) #x3333) (fix:and x1 #x3333)))
-           (x3 (fix:and (fix:+ x2 (fix:lsh x2 4)) #x0f0f))
+           (x3 (fix:and (fix:+ x2 (fix:lsh x2 -4)) #x0f0f))
            (c0 x3)
            (c1 (fix:lsh x3 -8))
            (s (fix:+ c0 c1)))
        (declare (integrate x1 x2 x3 x4 c0 c1 s))
-       (fix:and s #xf)))
+       (fix:and s #x1f)))
 
    (declare (integrate-operator fix:clz16))
    (define (fix:clz16 x)