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/* Round double to integer away from zero.
Copyright (C) 1997-2016 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
<http://www.gnu.org/licenses/>. */
#include <math.h>
#include <math_private.h>
#include <stdint.h>
static const double huge = 1.0e300;
double
__round (double x)
{
int64_t i0, j0;
EXTRACT_WORDS64 (i0, x);
j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
if (__glibc_likely (j0 < 52))
{
if (j0 < 0)
{
math_force_eval (huge + x);
i0 &= UINT64_C(0x8000000000000000);
if (j0 == -1)
i0 |= UINT64_C(0x3ff0000000000000);
}
else
{
uint64_t i = UINT64_C(0x000fffffffffffff) >> j0;
if ((i0 & i) == 0)
/* X is integral. */
return x;
math_force_eval (huge + x);
/* Raise inexact if x != 0. */
i0 += UINT64_C(0x0008000000000000) >> j0;
i0 &= ~i;
}
}
else
{
if (j0 == 0x400)
/* Inf or NaN. */
return x + x;
else
return x;
}
INSERT_WORDS64 (x, i0);
return x;
}
weak_alias (__round, round)
#ifdef NO_LONG_DOUBLE
strong_alias (__round, __roundl)
weak_alias (__round, roundl)
#endif
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