1 // Low-level type for atomic operations -*- C++ -*-
2
3 // Copyright (C) 2004-2013 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