File: peterson.pml

package info (click to toggle)
spin 6.4.9%2Bdfsg-1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 2,136 kB
  • sloc: ansic: 39,791; yacc: 1,015; makefile: 40; sh: 8
file content (20 lines) | stat: -rw-r--r-- 340 bytes parent folder | download | duplicates (4) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
/* Peterson's solution to the mutual exclusion problem - 1981 */

bool turn, flag[2];
byte ncrit;

active [2] proctype user()
{
	assert(_pid == 0 || _pid == 1);
again:
	flag[_pid] = 1;
	turn = _pid;
	(flag[1 - _pid] == 0 || turn == 1 - _pid);

	ncrit++;
	assert(ncrit == 1);	/* critical section */
	ncrit--;

	flag[_pid] = 0;
	goto again
}