1// Low-level functions for atomic operations: PA-RISC version  -*- C++ -*-
2
3// Copyright (C) 2002, 2004, 2005 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 2, 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// You should have received a copy of the GNU General Public License along
17// with this library; see the file COPYING.  If not, write to the Free
18// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
19// USA.
20
21// As a special exception, you may use this file as part of a free software
22// library without restriction.  Specifically, if other files instantiate
23// templates or use macros or inline functions from this file, or you compile
24// this file and link it with other files to produce an executable, this
25// file does not by itself cause the resulting executable to be covered by
26// the GNU General Public License.  This exception does not however
27// invalidate any other reasons why the executable file might be covered by
28// the GNU General Public License.
29
30#include <bits/c++config.h>
31#include <ext/atomicity.h>
32
33_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
34
35  template<int _Inst>
36    struct _Atomicity_lock
37    {
38      static volatile int _S_atomicity_lock;
39    };
40
41  template<int _Inst>
42  volatile int
43  _Atomicity_lock<_Inst>::_S_atomicity_lock __attribute__ ((aligned (16))) = 1;
44
45  // Because of the lack of weak support when using the hpux som
46  // linker, we explicitly instantiate the atomicity lock.
47  template volatile int _Atomicity_lock<0>::_S_atomicity_lock;
48
49  int
50  __attribute__ ((__unused__))
51  __exchange_and_add(volatile _Atomic_word* __mem, int __val)
52  {
53    _Atomic_word result;
54    int tmp;
55    volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
56
57    __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
58			  "cmpib,<>,n 0,%0,.+20\n\t"
59			  "ldw 0(%1),%0\n\t"
60			  "cmpib,= 0,%0,.-4\n\t"
61			  "nop\n\t"
62			  "b,n .-20"
63			  : "=&r" (tmp)
64			  : "r" (&lock)
65			  : "memory");
66
67    result = *__mem;
68    *__mem = result + __val;
69    __asm__ __volatile__ ("stw %1,0(%0)"
70			  : : "r" (&lock), "r" (tmp) : "memory");
71    return result;
72  }
73
74  void
75  __attribute__ ((__unused__))
76  __atomic_add(volatile _Atomic_word* __mem, int __val)
77  {
78    int tmp;
79    volatile int& lock = _Atomicity_lock<0>::_S_atomicity_lock;
80
81    __asm__ __volatile__ ("ldcw 0(%1),%0\n\t"
82			  "cmpib,<>,n 0,%0,.+20\n\t"
83			  "ldw 0(%1),%0\n\t"
84			  "cmpib,= 0,%0,.-4\n\t"
85			  "nop\n\t"
86			  "b,n .-20"
87			  : "=&r" (tmp)
88			  : "r" (&lock)
89			  : "memory");
90
91    *__mem += __val;
92    __asm__ __volatile__ ("stw %1,0(%0)"
93			  : : "r" (&lock), "r" (tmp) : "memory");
94  }
95
96_GLIBCXX_END_NAMESPACE
97