mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-25 14:30:06 +00:00
111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/* Compute remainder and a congruent to the quotient.
|
|
Copyright (C) 1997-2024 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 <libm-alias-double.h>
|
|
#include <stdint.h>
|
|
|
|
static const double zero = 0.0;
|
|
|
|
|
|
double
|
|
__remquo (double x, double y, int *quo)
|
|
{
|
|
int64_t hx, hy;
|
|
uint64_t sx, qs;
|
|
int cquo;
|
|
|
|
EXTRACT_WORDS64 (hx, x);
|
|
EXTRACT_WORDS64 (hy, y);
|
|
sx = hx & UINT64_C(0x8000000000000000);
|
|
qs = sx ^ (hy & UINT64_C(0x8000000000000000));
|
|
hy &= UINT64_C(0x7fffffffffffffff);
|
|
hx &= UINT64_C(0x7fffffffffffffff);
|
|
|
|
/* Purge off exception values. */
|
|
if (__glibc_unlikely (hy == 0))
|
|
return (x * y) / (x * y); /* y = 0 */
|
|
if (__builtin_expect (hx >= UINT64_C(0x7ff0000000000000) /* x not finite */
|
|
|| hy > UINT64_C(0x7ff0000000000000), 0))/* y is NaN */
|
|
return (x * y) / (x * y);
|
|
|
|
if (hy <= UINT64_C(0x7fbfffffffffffff))
|
|
x = __ieee754_fmod (x, 8 * y); /* now x < 8y */
|
|
|
|
if (__glibc_unlikely (hx == hy))
|
|
{
|
|
*quo = qs ? -1 : 1;
|
|
return zero * x;
|
|
}
|
|
|
|
x = fabs (x);
|
|
INSERT_WORDS64 (y, hy);
|
|
cquo = 0;
|
|
|
|
if (hy <= UINT64_C(0x7fcfffffffffffff) && x >= 4 * y)
|
|
{
|
|
x -= 4 * y;
|
|
cquo += 4;
|
|
}
|
|
if (hy <= UINT64_C(0x7fdfffffffffffff) && x >= 2 * y)
|
|
{
|
|
x -= 2 * y;
|
|
cquo += 2;
|
|
}
|
|
|
|
if (hy < UINT64_C(0x0020000000000000))
|
|
{
|
|
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)
|