// Low-level type 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, // 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 <cxxabi.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