[src/trunk]: src/lib/libm/src Casting is a not a valid way to check for overf...

[joerg <joerg%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/29cc192158f2
branches:  trunk
changeset: 786375:29cc192158f2
user:      joerg <joerg%NetBSD.org@localhost>
date:      Sat Apr 27 17:19:47 2013 +0000

description:
Casting is a not a valid way to check for overflow, so be explicit and
use the limit macros.

diffstat:

 lib/libm/src/s_scalbln.c |  47 +++++++++++++++++------------------------------
 1 files changed, 17 insertions(+), 30 deletions(-)

diffs (82 lines):

diff -r fb8ec79822c6 -r 29cc192158f2 lib/libm/src/s_scalbln.c
--- a/lib/libm/src/s_scalbln.c  Sat Apr 27 17:16:43 2013 +0000
+++ b/lib/libm/src/s_scalbln.c  Sat Apr 27 17:19:47 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: s_scalbln.c,v 1.3 2013/04/27 16:43:13 joerg Exp $      */
+/*     $NetBSD: s_scalbln.c,v 1.4 2013/04/27 17:19:47 joerg Exp $      */
 
 /*-
  * Copyright (c) 2004 David Schultz <das%FreeBSD.ORG@localhost>
@@ -30,7 +30,7 @@
 #if 0
 __FBSDID("$FreeBSD: src/lib/msun/src/s_scalbln.c,v 1.2 2005/03/07 04:57:50 das Exp $");
 #else
-__RCSID("$NetBSD: s_scalbln.c,v 1.3 2013/04/27 16:43:13 joerg Exp $");
+__RCSID("$NetBSD: s_scalbln.c,v 1.4 2013/04/27 17:19:47 joerg Exp $");
 #endif
 
 #include "namespace.h"
@@ -42,32 +42,24 @@
 double
 scalbln (double x, long n)
 {
-       int in;
 
-       in = (int)n;
-       if (in != n) {
-               if (n > 0)
-                       in = INT_MAX;
-               else
-                       in = INT_MIN;
-       }
-       return (scalbn(x, in));
+       if (n > INT_MAX)
+               n = INT_MAX;
+       else if (n < INT_MIN)
+               n = INT_MIN;
+       return (scalbn(x, n));
 }
 
 __weak_alias(scalblnf, _scalblnf)
 float
 scalblnf (float x, long n)
 {
-       int in;
 
-       in = (int)n;
-       if (in != n) {
-               if (n > 0)
-                       in = INT_MAX;
-               else
-                       in = INT_MIN;
-       }
-       return (scalbnf(x, in));
+       if (n > INT_MAX)
+               n = INT_MAX;
+       else if (n < INT_MIN)
+               n = INT_MIN;
+       return (scalbnf(x, n));
 }
 
 #ifndef _LP64
@@ -76,15 +68,10 @@
 long double
 scalblnl (long double x, long n)
 {
-       int in;
-
-       in = (int)n;
-       if (in != n) {
-               if (n > 0)
-                       in = INT_MAX;
-               else
-                       in = INT_MIN;
-       }
-       return (scalbnl(x, (int)n));
+       if (n > INT_MAX)
+               n = INT_MAX;
+       else if (n < INT_MIN)
+               n = INT_MIN;
+       return (scalbnl(x, n));
 }
 #endif