1// Low-level type for atomic operations -*- C++ -*- 2 3// Copyright (C) 2004, 2009 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 32typedef 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