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/* Compute remainder and a congruent to the quotient.
Copyright (C) 1997-2019 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, see
<https://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <libm-alias-double.h>
static const double zero = 0.0;
double
__remquo (double x, double y, int *quo)
{
int32_t hx, hy;
uint32_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 (hy <= 0x7fcfffff && x >= 4 * y)
{
x -= 4 * y;
cquo += 4;
}
if (hy <= 0x7fdfffff && 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;
/* Ensure correct sign of zero result in round-downward mode. */
if (x == 0.0)
x = 0.0;
if (sx)
x = -x;
return x;
}
libm_alias_double (__remquo, remquo)
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