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      1 // Low-level functions for atomic operations: PA-RISC version  -*- C++ -*-
      2 
      3 // Copyright (C) 2002-2024 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
    104