mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-15 01:21:06 +00:00
94 lines
2.0 KiB
C
94 lines
2.0 KiB
C
/* Round double to integer away from zero.
|
|
Copyright (C) 1997-2013 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>
|
|
|
|
|
|
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
|