X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fldexpl.c;h=b900d050ca7d403ac0a7fca318214a500575020d;hb=cd56634a4a8179fd5a4419fbb3e27211b042ab1c;hp=f85847b24e9d2e7c119a4344806b0696dd426971;hpb=55eed6bbc87934f2db04981e6f0f1773ff77974f;p=gnulib.git

diff --git a/lib/ldexpl.c b/lib/ldexpl.c
index f85847b24..b900d050c 100644
--- a/lib/ldexpl.c
+++ b/lib/ldexpl.c
@@ -1,57 +1,82 @@
 /* Emulation for ldexpl.
    Contributed by Paolo Bonzini
 
-   Copyright 2002, 2003, 2007 Free Software Foundation, Inc.
+   Copyright 2002-2003, 2007-2014 Free Software Foundation, Inc.
 
    This file is part of gnulib.
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
-   You should have received a copy of the GNU General Public License along
-   with this program; if not, write to the Free Software Foundation,
-   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
 /* Specification.  */
 #include <math.h>
 
-#include <float.h>
-#include "isnanl.h"
+#if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
 
 long double
-ldexpl(long double x, int exp)
+ldexpl (long double x, int exp)
+{
+  return ldexp (x, exp);
+}
+
+#else
+
+# include <float.h>
+# include "fpucw.h"
+
+long double
+ldexpl (long double x, int exp)
 {
   long double factor;
   int bit;
+  DECL_LONG_DOUBLE_ROUNDING
 
-  /* Check for zero, nan and infinity. */
-  if (isnanl (x) || x + x == x)
-    return x;
+  BEGIN_LONG_DOUBLE_ROUNDING ();
 
-  if (exp < 0)
+  /* Check for zero, nan and infinity. */
+  if (!(isnanl (x) || x + x == x))
     {
-      exp = -exp;
-      factor = 0.5L;
+      if (exp < 0)
+        {
+          exp = -exp;
+          factor = 0.5L;
+        }
+      else
+        factor = 2.0L;
+
+      if (exp > 0)
+        for (bit = 1;;)
+          {
+            /* Invariant: Here bit = 2^i, factor = 2^-2^i or = 2^2^i,
+               and bit <= exp.  */
+            if (exp & bit)
+              x *= factor;
+            bit <<= 1;
+            if (bit > exp)
+              break;
+            factor = factor * factor;
+          }
     }
-  else
-    factor = 2.0L;
 
-  for (bit = 1; bit <= exp; bit <<= 1, factor *= factor)
-    if (exp & bit)
-      x *= factor;
+  END_LONG_DOUBLE_ROUNDING ();
 
   return x;
 }
 
+#endif
+
 #if 0
 int
 main (void)
@@ -59,6 +84,6 @@ main (void)
   long double x;
   int y;
   for (y = 0; y < 29; y++)
-    printf ("%5d %.16Lg %.16Lg\n", y, ldexpl(0.8L, y), ldexpl(0.8L, -y) * ldexpl(0.8L, y));
+    printf ("%5d %.16Lg %.16Lg\n", y, ldexpl (0.8L, y), ldexpl (0.8L, -y) * ldexpl (0.8L, y));
 }
 #endif