1  // Low-level functions for atomic operations: PA-RISC version  -*- C++ -*-
       2  
       3  // Copyright (C) 2002-2023 Free Software Foundation, Inc.
       4  //
       5  // This file is part of the GNU ISO C++ Library.  This library is free
       6  // software; you can redistribute it and/or modify it under the
       7  // terms of the GNU General Public License as published by the
       8  // Free Software Foundation; either version 3, or (at your option)
       9  // any later version.
      10  
      11  // This library is distributed in the hope that it will be useful,
      12  // but WITHOUT ANY WARRANTY; without even the implied warranty of
      13  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14  // GNU General Public License for more details.
      15  
      16  // Under Section 7 of GPL version 3, you are granted additional
      17  // permissions described in the GCC Runtime Library Exception, version
      18  // 3.1, as published by the Free Software Foundation.
      19  
      20  // You should have received a copy of the GNU General Public License and
      21  // a copy of the GCC Runtime Library Exception along with this program;
      22  // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
      23  // <http://www.gnu.org/licenses/>.
      24  
      25  #include <bits/c++config.h>
      26  #include <ext/atomicity.h>
      27  
      28  /* Perform ldcw operation in cache when possible.  */
      29  #ifndef _PA_LDCW_INSN
      30  # ifdef _PA_RISC2_0
      31  # define _PA_LDCW_INSN "ldcw,co"
      32  # else
      33  # define _PA_LDCW_INSN "ldcw"
      34  # endif
      35  #endif
      36  
      37  namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
      38  {
      39  _GLIBCXX_BEGIN_NAMESPACE_VERSION
      40  
      41    template<int _Inst>
      42      struct _Atomicity_lock
      43      {
      44        static volatile int _S_atomicity_lock;
      45      };
      46  
      47    template<int _Inst>
      48    volatile int
      49    _Atomicity_lock<_Inst>::_S_atomicity_lock __attribute__ ((aligned (16))) = 1;
      50  
      51    // Because of the lack of weak support when using the hpux som
      52    // linker, we explicitly instantiate the atomicity lock.
      53    template volatile int _Atomicity_lock<0>::_S_atomicity_lock;
      54  
      55    int
      56    __attribute__ ((__unused__))
      57    __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
      58    {
      59      _Atomic_word result;
      60      int tmp;
      61      volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
      62  
      63      __asm__ __volatile__ (_PA_LDCW_INSN " 0(%1),%0\n\t"
      64  			  "cmpib,<>,n 0,%0,.+20\n\t"
      65  			  "ldw,ma 0(%1),%0\n\t"
      66  			  "cmpib,<> 0,%0,.-12\n\t"
      67  			  "nop\n\t"
      68  			  "b,n .-12"
      69  			  : "=&r" (tmp)
      70  			  : "r" (&lock)
      71  			  : "memory");
      72  
      73      result = *__mem;
      74      *__mem = result + __val;
      75      __asm__ __volatile__ ("stw,ma %1,0(%0)"
      76  			  : : "r" (&lock), "r" (tmp) : "memory");
      77      return result;
      78    }
      79  
      80    void
      81    __attribute__ ((__unused__))
      82    __atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
      83    {
      84      int tmp;
      85      volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
      86  
      87      __asm__ __volatile__ (_PA_LDCW_INSN " 0(%1),%0\n\t"
      88  			  "cmpib,<>,n 0,%0,.+20\n\t"
      89  			  "ldw,ma 0(%1),%0\n\t"
      90  			  "cmpib,<> 0,%0,.-12\n\t"
      91  			  "nop\n\t"
      92  			  "b,n .-12"
      93  			  : "=&r" (tmp)
      94  			  : "r" (&lock)
      95  			  : "memory");
      96  
      97      *__mem += __val;
      98      __asm__ __volatile__ ("stw,ma %1,0(%0)"
      99  			  : : "r" (&lock), "r" (tmp) : "memory");
     100    }
     101  
     102  _GLIBCXX_END_NAMESPACE_VERSION
     103  } // namespace