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      1 // Low-level functions for atomic operations: PA-RISC version  -*- C++ -*-
      2 
      3 // Copyright (C) 2002-2022 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 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
     29 {
     30 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     31 
     32   template<int _Inst>
     33     struct _Atomicity_lock
     34     {
     35       static volatile int _S_atomicity_lock;
     36     };
     37 
     38   template<int _Inst>
     39   volatile int
     40   _Atomicity_lock<_Inst>::_S_atomicity_lock __attribute__ ((aligned (16))) = 1;
     41 
     42   // Because of the lack of weak support when using the hpux som
     43   // linker, we explicitly instantiate the atomicity lock.
     44   template volatile int _Atomicity_lock<0>::_S_atomicity_lock;
     45 
     46   int
     47   __attribute__ ((__unused__))
     48   __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
     49   {
     50     _Atomic_word result;
     51     int tmp;
     52     volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
     53 
     54     __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
     55 			  "cmpib,<>,n 0,%0,.+20\n\t"
     56 			  "ldw 0(%1),%0\n\t"
     57 			  "cmpib,= 0,%0,.-4\n\t"
     58 			  "nop\n\t"
     59 			  "b,n .-20"
     60 			  : "=&r" (tmp)
     61 			  : "r" (&lock)
     62 			  : "memory");
     63 
     64     result = *__mem;
     65     *__mem = result + __val;
     66     __asm__ __volatile__ ("stw %1,0(%0)"
     67 			  : : "r" (&lock), "r" (tmp) : "memory");
     68     return result;
     69   }
     70 
     71   void
     72   __attribute__ ((__unused__))
     73   __atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
     74   {
     75     int tmp;
     76     volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
     77 
     78     __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
     79 			  "cmpib,<>,n 0,%0,.+20\n\t"
     80 			  "ldw 0(%1),%0\n\t"
     81 			  "cmpib,= 0,%0,.-4\n\t"
     82 			  "nop\n\t"
     83 			  "b,n .-20"
     84 			  : "=&r" (tmp)
     85 			  : "r" (&lock)
     86 			  : "memory");
     87 
     88     *__mem += __val;
     89     __asm__ __volatile__ ("stw %1,0(%0)"
     90 			  : : "r" (&lock), "r" (tmp) : "memory");
     91   }
     92 
     93 _GLIBCXX_END_NAMESPACE_VERSION
     94 } // namespace
     95