/* Emulation for ldexpl.
Contributed by Paolo Bonzini
- Copyright 2002, 2003 Free Software Foundation, Inc.
+ Copyright 2002-2003, 2007-2013 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 <float.h>
+#include <config.h>
+
+/* Specification. */
#include <math.h>
-#include "mathl.h"
+#if HAVE_SAME_LONG_DOUBLE_AS_DOUBLE
+
+long double
+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)
+ldexpl (long double x, int exp)
{
long double factor;
int bit;
+ DECL_LONG_DOUBLE_ROUNDING
- /* Check for zero, nan and infinity. */
- if (x != 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)
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