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// Low-level functions for atomic operations: Generic version  -*- C++ -*-

// Copyright (C) 1999, 2001, 2002, 2003, 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.

#include <bits/atomicity.h>

#include <bits/concurrence.h>

namespace __gnu_internal

{

  __glibcxx_mutex_define_initialized(atomic_mutex);

} // namespace __gnu_internal

namespace __gnu_cxx

{

  _Atomic_word

  __attribute__ ((__unused__))

  __exchange_and_add(volatile _Atomic_word* __mem, int __val)

  {

    __glibcxx_mutex_lock(__gnu_internal::atomic_mutex);

    _Atomic_word __result;

    __result = *__mem;

    *__mem += __val;

    __glibcxx_mutex_unlock(__gnu_internal::atomic_mutex);

    return __result;

  }

  void

  __attribute__ ((__unused__))

  __atomic_add(volatile _Atomic_word* __mem, int __val)

  { __exchange_and_add(__mem, __val); }

} // namespace __gnu_cxx