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/* Compute remainder and a congruent to the quotient.
Copyright (C) 1997-2025 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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 <math_ldbl_opt.h>
static const long double zero = 0.0;
long double
__remquol (long double x, long double y, int *quo)
{
int64_t hx,hy;
uint64_t sx,lx,ly,qs;
int cquo;
double xhi, xlo, yhi, ylo;
ldbl_unpack (x, &xhi, &xlo);
EXTRACT_WORDS64 (hx, xhi);
EXTRACT_WORDS64 (lx, xlo);
ldbl_unpack (y, &yhi, &ylo);
EXTRACT_WORDS64 (hy, yhi);
EXTRACT_WORDS64 (ly, ylo);
sx = hx & 0x8000000000000000ULL;
qs = sx ^ (hy & 0x8000000000000000ULL);
ly ^= hy & 0x8000000000000000ULL;
hy &= 0x7fffffffffffffffLL;
lx ^= sx;
hx &= 0x7fffffffffffffffLL;
/* Purge off exception values. */
if (hy == 0)
return (x * y) / (x * y); /* y = 0 */
if ((hx >= 0x7ff0000000000000LL) /* x not finite */
|| (hy > 0x7ff0000000000000LL)) /* y is NaN */
return (x * y) / (x * y);
if (hy <= 0x7fbfffffffffffffLL)
x = __ieee754_fmodl (x, 8 * y); /* now x < 8y */
if (((hx - hy) | (lx - ly)) == 0)
{
*quo = qs ? -1 : 1;
return zero * x;
}
x = fabsl (x);
y = fabsl (y);
cquo = 0;
if (hy <= 0x7fcfffffffffffffLL && x >= 4 * y)
{
x -= 4 * y;
cquo += 4;
}
if (hy <= 0x7fdfffffffffffffLL && x >= 2 * y)
{
x -= 2 * y;
cquo += 2;
}
if (hy < 0x0020000000000000LL)
{
if (x + x > y)
{
x -= y;
++cquo;
if (x + x >= y)
{
x -= y;
++cquo;
}
}
}
else
{
long double y_half = 0.5L * 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 == 0.0L)
x = 0.0L;
if (sx)
x = -x;
return x;
}
long_double_symbol (libm, __remquol, remquol);
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