glibc/sysdeps/i386/fpu/s_fdim.c
Paul Eggert 2b778ceb40 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
2021-01-02 12:17:34 -08:00

48 lines
1.6 KiB
C

/* Return positive difference between arguments. i386 version.
Copyright (C) 1997-2021 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
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <fpu_control.h>
#include <math.h>
#include <math-narrow-eval.h>
#include <libm-alias-double.h>
double
__fdim (double x, double y)
{
if (islessequal (x, y))
return 0.0;
/* To avoid double rounding, set double precision for the
subtraction. math_narrow_eval is still needed to eliminate
excess range in the case of overflow. If the result of the
subtraction is in the subnormal range for double, it is exact, so
no issues of double rounding for subnormals arise. */
fpu_control_t cw, cw_double;
_FPU_GETCW (cw);
cw_double = (cw & ~_FPU_EXTENDED) | _FPU_DOUBLE;
_FPU_SETCW (cw_double);
double r = math_narrow_eval (x - y);
_FPU_SETCW (cw);
if (isinf (r) && !isinf (x) && !isinf (y))
__set_errno (ERANGE);
return r;
}
libm_alias_double (__fdim, fdim)