1 | // Low-level type for atomic operations -*- C++ -*- |
2 | |
3 | // Copyright (C) 2004-2014 Free Software Foundation, Inc. |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free |
6 | // software; you can redistribute it and/or modify it under the |
7 | // terms of the GNU General Public License as published by the |
8 | // Free Software Foundation; either version 3, or (at your option) |
9 | // any later version. |
10 | |
11 | // This library is distributed in the hope that it will be useful, |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | // GNU General Public License for more details. |
15 | |
16 | // Under Section 7 of GPL version 3, you are granted additional |
17 | // permissions described in the GCC Runtime Library Exception, version |
18 | // 3.1, as published by the Free Software Foundation. |
19 | |
20 | // You should have received a copy of the GNU General Public License and |
21 | // a copy of the GCC Runtime Library Exception along with this program; |
22 | // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
23 | // <http://www.gnu.org/licenses/>. |
24 | |
25 | /** @file atomic_word.h |
26 | * This file is a GNU extension to the Standard C++ Library. |
27 | */ |
28 | |
29 | #ifndef _GLIBCXX_ATOMIC_WORD_H |
30 | #define _GLIBCXX_ATOMIC_WORD_H 1 |
31 | |
32 | typedef int _Atomic_word; |
33 | |
34 | // Define these two macros using the appropriate memory barrier for the target. |
35 | // The commented out versions below are the defaults. |
36 | // See ia64/atomic_word.h for an alternative approach. |
37 | |
38 | // This one prevents loads from being hoisted across the barrier; |
39 | // in other words, this is a Load-Load acquire barrier. |
40 | // This is necessary iff TARGET_RELAXED_ORDERING is defined in tm.h. |
41 | // #define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory") |
42 | |
43 | // This one prevents stores from being sunk across the barrier; in other |
44 | // words, a Store-Store release barrier. |
45 | // #define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory") |
46 | |
47 | #endif |
48 | |