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ldexpl.c
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ldexpl.c
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/******************************** -*- C -*- ****************************
*
* Emulation for ldexpl
*
*
***********************************************************************/
/***********************************************************************
*
* Copyright 2002 Free Software Foundation, Inc.
* Written by Paolo Bonzini.
*
* This file is part of GNU Smalltalk.
*
* GNU Smalltalk 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.
*
* GNU Smalltalk 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
* GNU Smalltalk; see the file COPYING. If not, write to the Free Software
* Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
***********************************************************************/
#include <float.h>
#include <math.h>
#include "mathl.h"
long double
ldexpl(long double x, int exp)
{
long double factor;
int bit;
/* Check for zero, nan and infinity. */
if (x != x || x + x == x )
return x;
if (exp < 0)
{
exp = -exp;
factor = 0.5L;
}
else
factor = 2.0L;
for (bit = 1; bit <= exp; bit <<= 1, factor *= factor)
if (exp & bit)
x *= factor;
return x;
}
#if 0
int
main()
{
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));
}
#endif