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// Low-level type for atomic operations -*- C++ -*-
// Copyright (C) 2004, 2005, 2006, 2007, 2009 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 3, 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.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#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
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