1// Low-level functions for atomic operations: PA-RISC version  -*- C++ -*-
2
3// Copyright (C) 2002, 2004, 2005, 2009 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_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
29
30  template<int _Inst>
31    struct _Atomicity_lock
32    {
33      static volatile int _S_atomicity_lock;
34    };
35
36  template<int _Inst>
37  volatile int
38  _Atomicity_lock<_Inst>::_S_atomicity_lock __attribute__ ((aligned (16))) = 1;
39
40  // Because of the lack of weak support when using the hpux som
41  // linker, we explicitly instantiate the atomicity lock.
42  template volatile int _Atomicity_lock<0>::_S_atomicity_lock;
43
44  int
45  __attribute__ ((__unused__))
46  __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
47  {
48    _Atomic_word result;
49    int tmp;
50    volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
51
52    __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
53			  "cmpib,<>,n 0,%0,.+20\n\t"
54			  "ldw 0(%1),%0\n\t"
55			  "cmpib,= 0,%0,.-4\n\t"
56			  "nop\n\t"
57			  "b,n .-20"
58			  : "=&r" (tmp)
59			  : "r" (&lock)
60			  : "memory");
61
62    result = *__mem;
63    *__mem = result + __val;
64    __asm__ __volatile__ ("stw %1,0(%0)"
65			  : : "r" (&lock), "r" (tmp) : "memory");
66    return result;
67  }
68
69  void
70  __attribute__ ((__unused__))
71  __atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
72  {
73    int tmp;
74    volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
75
76    __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
77			  "cmpib,<>,n 0,%0,.+20\n\t"
78			  "ldw 0(%1),%0\n\t"
79			  "cmpib,= 0,%0,.-4\n\t"
80			  "nop\n\t"
81			  "b,n .-20"
82			  : "=&r" (tmp)
83			  : "r" (&lock)
84			  : "memory");
85
86    *__mem += __val;
87    __asm__ __volatile__ ("stw %1,0(%0)"
88			  : : "r" (&lock), "r" (tmp) : "memory");
89  }
90
91_GLIBCXX_END_NAMESPACE
92