glibc/sysdeps/ieee754/dbl-64/s_remquo.c
Andreas Jaeger 41bdb6e20c Update to LGPL v2.1.
2001-07-06  Paul Eggert  <eggert@twinsun.com>

	* manual/argp.texi: Remove ignored LGPL copyright notice; it's
	not appropriate for documentation anyway.
	* manual/libc-texinfo.sh: "Library General Public License" ->
	"Lesser General Public License".

2001-07-06  Andreas Jaeger  <aj@suse.de>

	* All files under GPL/LGPL version 2: Place under LGPL version
	2.1.
2001-07-06 04:58:11 +00:00

114 lines
2.4 KiB
C

/* Compute remainder and a congruent to the quotient.
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <math.h>
#include "math_private.h"
static const double zero = 0.0;
double
__remquo (double x, double y, int *quo)
{
int32_t hx,hy;
u_int32_t sx,lx,ly;
int cquo, qs;
EXTRACT_WORDS (hx, lx, x);
EXTRACT_WORDS (hy, ly, y);
sx = hx & 0x80000000;
qs = sx ^ (hy & 0x80000000);
hy &= 0x7fffffff;
hx &= 0x7fffffff;
/* Purge off exception values. */
if ((hy | ly) == 0)
return (x * y) / (x * y); /* y = 0 */
if ((hx >= 0x7ff00000) /* x not finite */
|| ((hy >= 0x7ff00000) /* p is NaN */
&& (((hy - 0x7ff00000) | ly) != 0)))
return (x * y) / (x * y);
if (hy <= 0x7fbfffff)
x = __ieee754_fmod (x, 8 * y); /* now x < 8y */
if (((hx - hy) | (lx - ly)) == 0)
{
*quo = qs ? -1 : 1;
return zero * x;
}
x = fabs (x);
y = fabs (y);
cquo = 0;
if (x >= 4 * y)
{
x -= 4 * y;
cquo += 4;
}
if (x >= 2 * y)
{
x -= 2 * y;
cquo += 2;
}
if (hy < 0x00200000)
{
if (x + x > y)
{
x -= y;
++cquo;
if (x + x >= y)
{
x -= y;
++cquo;
}
}
}
else
{
double y_half = 0.5 * y;
if (x > y_half)
{
x -= y;
++cquo;
if (x >= y_half)
{
x -= y;
++cquo;
}
}
}
*quo = qs ? -cquo : cquo;
if (sx)
x = -x;
return x;
}
weak_alias (__remquo, remquo)
#ifdef NO_LONG_DOUBLE
strong_alias (__remquo, __remquol)
weak_alias (__remquo, remquol)
#endif