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656c7dc1 MD |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify | |
3 | * it under the terms of the GNU General Public License as published by | |
4 | * the Free Software Foundation; either version 2 of the License, or | |
5 | * (at your option) any later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
15 | * | |
16 | * Copyright (c) 2009 Mathieu Desnoyers | |
17 | */ | |
18 | ||
19 | byte lock = 0; | |
20 | byte refcount = 0; | |
21 | ||
22 | inline spin_lock(lock) | |
23 | { | |
24 | do | |
25 | :: 1 -> atomic { | |
26 | if | |
27 | :: (lock) -> | |
28 | skip; | |
29 | :: else -> | |
30 | lock = 1; | |
31 | break; | |
32 | fi; | |
33 | } | |
34 | od; | |
35 | } | |
36 | ||
37 | inline spin_unlock(lock) | |
38 | { | |
39 | lock = 0; | |
40 | } | |
41 | ||
42 | proctype proc_A() | |
43 | { | |
44 | do | |
45 | :: 1-> | |
46 | progress_A: | |
47 | spin_lock(lock); | |
48 | refcount = refcount + 1; | |
49 | refcount = refcount - 1; | |
50 | spin_unlock(lock); | |
51 | od; | |
52 | } | |
53 | ||
54 | proctype proc_B() | |
55 | { | |
56 | do | |
57 | :: 1-> | |
58 | spin_lock(lock); | |
59 | refcount = refcount + 1; | |
60 | refcount = refcount - 1; | |
61 | spin_unlock(lock); | |
62 | od; | |
63 | } | |
64 | ||
65 | init | |
66 | { | |
67 | run proc_A(); | |
68 | run proc_B(); | |
69 | } |