| 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 | } |