X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fldexpl.c;h=4389f761b2442169d409ccb04bfee067fa4e4e47;hb=b344de996cd51f8a2f2558a3172016b64d99c622;hp=f85847b24e9d2e7c119a4344806b0696dd426971;hpb=55eed6bbc87934f2db04981e6f0f1773ff77974f;p=gnulib.git
diff --git a/lib/ldexpl.c b/lib/ldexpl.c
index f85847b24..4389f761b 100644
--- a/lib/ldexpl.c
+++ b/lib/ldexpl.c
@@ -1,23 +1,22 @@
/* Emulation for ldexpl.
Contributed by Paolo Bonzini
- Copyright 2002, 2003, 2007 Free Software Foundation, Inc.
+ Copyright 2002-2003, 2007-2011 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 . */
#include
@@ -25,29 +24,43 @@
#include
#include
-#include "isnanl.h"
+#include "fpucw.h"
long double
-ldexpl(long double x, int exp)
+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;
}
@@ -59,6 +72,6 @@ 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