// Low-level type for atomic operations -*- C++ -*-// Copyright (C) 2004, 2005, 2006, 2007 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.#ifndef _GLIBCXX_ATOMIC_WORD_H#define _GLIBCXX_ATOMIC_WORD_H 1#include <bits/cxxabi_tweaks.h>typedef int _Atomic_word;namespace __gnu_cxx{// Test the first byte of __g and ensure that no loads are hoisted across// the test.inline bool__test_and_acquire (__cxxabiv1::__guard *__g){unsigned char __c;unsigned char *__p = reinterpret_cast<unsigned char *>(__g);// ldN.acq is a load with an implied hoist barrier.// would ld8+mask be faster than just doing an ld1?__asm __volatile ("ld1.acq %0 = %1" : "=r"(__c) : "m"(*__p) : "memory");return __c != 0;}// Set the first byte of __g to 1 and ensure that no stores are sunk// across the store.inline void__set_and_release (__cxxabiv1::__guard *__g){unsigned char *__p = reinterpret_cast<unsigned char *>(__g);// stN.rel is a store with an implied sink barrier.// could load word, set flag, and CAS it back__asm __volatile ("st1.rel %0 = %1" : "=m"(*__p) : "r"(1) : "memory");}// We don't define the _BARRIER macros on ia64 because the barriers are// included in the test and set, above.#define _GLIBCXX_GUARD_TEST_AND_ACQUIRE(G) __gnu_cxx::__test_and_acquire (G)#define _GLIBCXX_GUARD_SET_AND_RELEASE(G) __gnu_cxx::__set_and_release (G)}#endif