mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-28 13:31:13 +00:00
688903eb3e
* All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/* Round to nearest integer value, rounding halfway cases to even.
|
|
ldbl-128ibm version.
|
|
Copyright (C) 2016-2018 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
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include <math.h>
|
|
#include <math_private.h>
|
|
|
|
long double
|
|
__roundevenl (long double x)
|
|
{
|
|
double xh, xl, hi;
|
|
|
|
ldbl_unpack (x, &xh, &xl);
|
|
|
|
if (xh != 0 && isfinite (xh))
|
|
{
|
|
hi = __roundeven (xh);
|
|
if (hi != xh)
|
|
{
|
|
/* The high part is not an integer; the low part only
|
|
affects the result if the high part is exactly half way
|
|
between two integers and the low part is nonzero in the
|
|
opposite direction to the rounding of the high part. */
|
|
double diff = hi - xh;
|
|
if (fabs (diff) == 0.5)
|
|
{
|
|
if (xl < 0 && diff > 0)
|
|
xh = hi - 1;
|
|
else if (xl > 0 && diff < 0)
|
|
xh = hi + 1;
|
|
else
|
|
xh = hi;
|
|
}
|
|
else
|
|
xh = hi;
|
|
xl = 0;
|
|
}
|
|
else
|
|
{
|
|
/* The high part is a nonzero integer. Rounding the low
|
|
part to nearest, ties round to even, is always correct,
|
|
as a high part that is an odd integer together with a low
|
|
part with magnitude 0.5 is not a valid long double. */
|
|
xl = __roundeven (xl);
|
|
xh = hi;
|
|
ldbl_canonicalize_int (&xh, &xl);
|
|
}
|
|
}
|
|
else
|
|
/* Quiet signaling NaN arguments. */
|
|
xh += xh;
|
|
|
|
return ldbl_pack (xh, xl);
|
|
}
|
|
weak_alias (__roundevenl, roundevenl)
|