about summary refs log tree commit diff
path: root/sysdeps/ieee754/ldbl-96/s_scalbnl.c
diff options
context:
space:
mode:
authorJoseph Myers <joseph@codesourcery.com>2012-03-02 15:32:56 +0000
committerJoseph Myers <joseph@codesourcery.com>2012-03-02 15:32:56 +0000
commita6d06d7b86f724046b462115556d0df682f9f703 (patch)
tree640870a7d978c8a224fe317e862b65fddba6f40e /sysdeps/ieee754/ldbl-96/s_scalbnl.c
parent07e12bb391ae84eb74817d42feda42cff7f687e5 (diff)
downloadglibc-a6d06d7b86f724046b462115556d0df682f9f703.tar.gz
glibc-a6d06d7b86f724046b462115556d0df682f9f703.tar.xz
glibc-a6d06d7b86f724046b462115556d0df682f9f703.zip
Fix scalbn, scalbln integer overflow.
Diffstat (limited to 'sysdeps/ieee754/ldbl-96/s_scalbnl.c')
-rw-r--r--sysdeps/ieee754/ldbl-96/s_scalbnl.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/sysdeps/ieee754/ldbl-96/s_scalbnl.c b/sysdeps/ieee754/ldbl-96/s_scalbnl.c
index 6a41920aca..6946cf232f 100644
--- a/sysdeps/ieee754/ldbl-96/s_scalbnl.c
+++ b/sysdeps/ieee754/ldbl-96/s_scalbnl.c
@@ -43,11 +43,13 @@ __scalbnl (long double x, int n)
 	    k = (hx&0x7fff) - 64;
 	    }
 	if (__builtin_expect(k==0x7fff, 0)) return x+x;	/* NaN or Inf */
-	k = k+n;
-	if (__builtin_expect(n> 50000 || k > 0x7ffe, 0))
-	  return huge*__copysignl(huge,x); /* overflow  */
 	if (__builtin_expect(n< -50000, 0))
 	  return tiny*__copysignl(tiny,x);
+	if (__builtin_expect(n> 50000 || k+n > 0x7ffe, 0))
+	  return huge*__copysignl(huge,x); /* overflow  */
+	/* Now k and n are bounded we know that k = k+n does not
+	   overflow.  */
+	k = k+n;
 	if (__builtin_expect(k > 0, 1))		/* normal result */
 	    {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;}
 	if (k <= -64)