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| 1 | /* Control when floating-point expressions are evaluated. Generic version. |
|---|---|
| 2 | Copyright (C) 2007-2022 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <https://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #ifndef _MATH_BARRIERS_H |
| 20 | #define _MATH_BARRIERS_H 1 |
| 21 | |
| 22 | /* math_opt_barrier evaluates and returns its floating-point argument |
| 23 | and ensures that the evaluation of any expression using the result |
| 24 | of math_opt_barrier is not moved before the call. math_force_eval |
| 25 | ensures that its floating-point argument is evaluated for its side |
| 26 | effects even if its value is apparently unused, and that the |
| 27 | evaluation of its argument is not moved after the call. Both these |
| 28 | macros are used to ensure the correct ordering of floating-point |
| 29 | expression evaluations with respect to accesses to the |
| 30 | floating-point environment. */ |
| 31 | |
| 32 | #define math_opt_barrier(x) \ |
| 33 | ({ __typeof (x) __x = (x); __asm ("" : "+m" (__x)); __x; }) |
| 34 | #define math_force_eval(x) \ |
| 35 | ({ __typeof (x) __x = (x); __asm __volatile__ ("" : : "m" (__x)); }) |
| 36 | |
| 37 | #endif /* math-barriers.h */ |
| 38 |
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