38 lines
1.7 KiB
C
38 lines
1.7 KiB
C
/* Control when floating-point expressions are evaluated. Generic version.
|
|
Copyright (C) 2007-2018 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/>. */
|
|
|
|
#ifndef _MATH_BARRIERS_H
|
|
#define _MATH_BARRIERS_H 1
|
|
|
|
/* math_opt_barrier evaluates and returns its floating-point argument
|
|
and ensures that the evaluation of any expression using the result
|
|
of math_opt_barrier is not moved before the call. math_force_eval
|
|
ensures that its floating-point argument is evaluated for its side
|
|
effects even if its value is apparently unused, and that the
|
|
evaluation of its argument is not moved after the call. Both these
|
|
macros are used to ensure the correct ordering of floating-point
|
|
expression evaluations with respect to accesses to the
|
|
floating-point environment. */
|
|
|
|
#define math_opt_barrier(x) \
|
|
({ __typeof (x) __x = (x); __asm ("" : "+m" (__x)); __x; })
|
|
#define math_force_eval(x) \
|
|
({ __typeof (x) __x = (x); __asm __volatile__ ("" : : "m" (__x)); })
|
|
|
|
#endif /* math-barriers.h */
|