atomicity.h revision 117397 
1// Low-level functions for atomic operations.
2
3// Copyright (C) 2001, 2002 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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#ifndef _BITS_ATOMICITY_H
31#define _BITS_ATOMICITY_H 1
32
33typedef int _Atomic_word;
34
35static inline int
36__attribute__ ((__unused__))
37__exchange_and_add (volatile _Atomic_word *__mem, int __val)
38{
39  int __result, __tmp;
40
41  __asm__ __volatile__
42    ("/* Inline exchange & add */\n\t"
43     "1:\n\t"
44     ".set	push\n\t"
45     ".set	mips2\n\t"
46     "ll	%0,%3\n\t"
47     "addu	%1,%4,%0\n\t"
48     "sc	%1,%2\n\t"
49     ".set	pop\n\t"
50     "beqz	%1,1b\n\t"
51     "/* End exchange & add */"
52     : "=&r"(__result), "=&r"(__tmp), "=m"(*__mem)
53     : "m" (*__mem), "r"(__val)
54     : "memory");
55
56  return __result;
57}
58
59static inline void
60__attribute__ ((__unused__))
61__atomic_add (volatile _Atomic_word *__mem, int __val)
62{
63  int __result;
64
65  __asm__ __volatile__
66    ("/* Inline atomic add */\n\t"
67     "1:\n\t"
68     ".set	push\n\t"
69     ".set	mips2\n\t"
70     "ll	%0,%2\n\t"
71     "addu	%0,%3,%0\n\t"
72     "sc	%0,%1\n\t"
73     ".set	pop\n\t"
74     "beqz	%0,1b\n\t"
75     "/* End atomic add */"
76     : "=&r"(__result), "=m"(*__mem)
77     : "m" (*__mem), "r"(__val)
78     : "memory");
79}
80
81#endif /* atomicity.h */
82