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/* Round double to integer away from zero.
Copyright (C) 1997, 2011 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <math.h>
#include "math_private.h"
static const double huge = 1.0e300;
double
__round (double x)
{
int32_t i0, j0;
u_int32_t i1;
EXTRACT_WORDS (i0, i1, x);
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
if (j0 < 20)
{
if (j0 < 0)
{
math_force_eval (huge + x);
i0 &= 0x80000000;
if (j0 == -1)
i0 |= 0x3ff00000;
i1 = 0;
}
else
{
u_int32_t i = 0x000fffff >> j0;
if (((i0 & i) | i1) == 0)
/* X is integral. */
return x;
math_force_eval (huge + x);
/* Raise inexact if x != 0. */
i0 += 0x00080000 >> j0;
i0 &= ~i;
i1 = 0;
}
}
else if (j0 > 51)
{
if (j0 == 0x400)
/* Inf or NaN. */
return x + x;
else
return x;
}
else
{
u_int32_t i = 0xffffffff >> (j0 - 20);
if ((i1 & i) == 0)
/* X is integral. */
return x;
math_force_eval (huge + x);
/* Raise inexact if x != 0. */
u_int32_t j = i1 + (1 << (51 - j0));
if (j < i1)
i0 += 1;
i1 = j;
i1 &= ~i;
}
INSERT_WORDS (x, i0, i1);
return x;
}
weak_alias (__round, round)
#ifdef NO_LONG_DOUBLE
strong_alias (__round, __roundl)
weak_alias (__round, roundl)
#endif
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