/* Emulation for ldexpl.
Contributed by Paolo Bonzini
- Copyright 2002, 2003 Free Software Foundation, Inc.
+ Copyright 2002, 2003, 2007 Free Software Foundation, Inc.
This file is part of gnulib.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
-#include <float.h>
+#include <config.h>
+
+/* Specification. */
#include <math.h>
-#include "mathl.h"
+#include <float.h>
+#include "fpucw.h"
+#include "isnanl.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 (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;
}