program test and set

var

disable1,disable2:boonlean;

active:boolean;

procedure process1

var

disable1:boonlean;

begin

while true do begin

....

disable1:=true;

while disable1=true do

test and set(disable1,active);

{critical region}

Active:=false;

.......

End;

End;

Procedure process2

Var

Disable2;boonlean;

Begin

While true do begin

.........

Disable2:=true;

While disable2=true;

Test and set(disable2,active);

{ critical region }

Active:=false;

.......

End;

End;

Begin

Active:=false;

Parbegin

Process1;

Process2;

Par end;

End;