+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (c) 2009 Mathieu Desnoyers
+ */
+
+byte lock = 0;
+byte refcount = 0;
+
+inline spin_lock(lock)
+{
+ do
+ :: 1 -> atomic {
+ if
+ :: (lock) ->
+ skip;
+ :: else ->
+ lock = 1;
+ break;
+ fi;
+ }
+ od;
+}
+
+inline spin_unlock(lock)
+{
+ lock = 0;
+}
+
+proctype proc_X()
+{
+ do
+ :: 1 ->
+ spin_lock(lock);
+ refcount = refcount + 1;
+ refcount = refcount - 1;
+ spin_unlock(lock);
+ od;
+}
+
+init
+{
+ run proc_X();
+ run proc_X();
+}