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
