// Low-level functions for atomic operations -*- C++ -*-// Copyright (C) 2004 Free Software Foundation, Inc.//// This file is part of the GNU ISO C++ Library. This library is free// software; you can redistribute it and/or modify it under the// terms of the GNU General Public License as published by the// Free Software Foundation; either version 2, or (at your option)// any later version.// This library is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.// You should have received a copy of the GNU General Public License along// with this library; see the file COPYING. If not, write to the Free// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,// USA.// As a special exception, you may use this file as part of a free software// library without restriction. Specifically, if other files instantiate// templates or use macros or inline functions from this file, or you compile// this file and link it with other files to produce an executable, this// file does not by itself cause the resulting executable to be covered by// the GNU General Public License. This exception does not however// invalidate any other reasons why the executable file might be covered by// the GNU General Public License./** @file atomicity.h* This is an internal header file, included by other library headers.* You should not attempt to use it directly.*/#ifndef _GLIBCXX_ATOMICITY_H#define _GLIBCXX_ATOMICITY_H 1#include <bits/atomic_word.h>namespace __gnu_cxx{_Atomic_word__attribute__ ((__unused__))__exchange_and_add(volatile _Atomic_word* __mem, int __val);void__attribute__ ((__unused__))__atomic_add(volatile _Atomic_word* __mem, int __val);} // namespace __gnu_cxx/* Even if the CPU doesn't need a memory barrier, we need to ensure thatthe compiler doesn't reorder memory accesses across the barriers. */#ifndef _GLIBCXX_READ_MEM_BARRIER#define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory")#endif#ifndef _GLIBCXX_WRITE_MEM_BARRIER#define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory")#endif#endif