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