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

// Copyright (C) 2002, 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/c++config.h>

#include <bits/atomicity.h>

namespace __gnu_cxx

{

  template<int _Inst>

    struct _Atomicity_lock

    {

      static volatile int _S_atomicity_lock;

    };

  template<int _Inst>

  volatile int

  _Atomicity_lock<_Inst>::_S_atomicity_lock __attribute__ ((aligned (16))) = 1;

  // Because of the lack of weak support when using the hpux som

  // linker, we explicitly instantiate the atomicity lock.

  template volatile int _Atomicity_lock<0>::_S_atomicity_lock;

  int

  __attribute__ ((__unused__))

  __exchange_and_add(volatile _Atomic_word* __mem, int __val)

  {

    _Atomic_word result;

    int tmp;

    volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;

    __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"

                          "cmpib,<>,n 0,%0,.+20\n\t"

                          "ldw 0(%1),%0\n\t"

                          "cmpib,= 0,%0,.-4\n\t"

                          "nop\n\t"

                          "b,n .-20"

                          : "=&r" (tmp)

                          : "r" (&lock)

                          : "memory");

    result = *__mem;

    *__mem = result + __val;

    /* Reset lock with PA 2.0 "ordered" store.  */

    __asm__ __volatile__ ("stw,ma %1,0(%0)"

                          : : "r" (&lock), "r" (tmp) : "memory");

    return result;

  }

  void

  __attribute__ ((__unused__))

  __atomic_add(volatile _Atomic_word* __mem, int __val)

  {

    int tmp;

    volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;

    __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"

                          "cmpib,<>,n 0,%0,.+20\n\t"

                          "ldw 0(%1),%0\n\t"

                          "cmpib,= 0,%0,.-4\n\t"

                          "nop\n\t"

                          "b,n .-20"

                          : "=&r" (tmp)

                          : "r" (&lock)

                          : "memory");

    *__mem += __val;

    /* Reset lock with PA 2.0 "ordered" store.  */

    __asm__ __volatile__ ("stw,ma %1,0(%0)"

                          : : "r" (&lock), "r" (tmp) : "memory");

  }

} // namespace __gnu_cxx