mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-25 06:20:06 +00:00
48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
/* Return positive difference between arguments. i386 version.
|
|
Copyright (C) 1997-2024 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)
|