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/* Round double to integer away from zero.
Copyright (C) 2011-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 2011.
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/>. */
/* Based on a version which carries the following copyright: */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#define NO_MATH_REDIRECT
#include <math.h>
#include <math_private.h>
#include <stdint.h>
#include <libm-alias-double.h>
#include <math-use-builtins.h>
/*
* floor(x)
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
*/
double
__floor (double x)
{
#if USE_FLOOR_BUILTIN
return __builtin_floor (x);
#else
/* Use generic implementation. */
int64_t i0;
EXTRACT_WORDS64 (i0, x);
int32_t j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
if (__glibc_likely (j0 < 52))
{
if (j0 < 0)
{
/* return 0 * sign (x) if |x| < 1 */
if (i0 >= 0)
i0 = 0;
else if ((i0 & 0x7fffffffffffffffl) != 0)
i0 = 0xbff0000000000000l;
}
else
{
uint64_t i = 0x000fffffffffffffl >> j0;
if ((i0 & i) == 0)
return x; /* x is integral */
if (i0 < 0)
i0 += 0x0010000000000000l >> j0;
i0 &= ~i;
}
INSERT_WORDS64 (x, i0);
}
else if (j0 == 0x400)
return x + x; /* inf or NaN */
return x;
#endif /* ! USE_FLOOR_BUILTIN */
}
#ifndef __floor
libm_alias_double (__floor, floor)
#endif
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