(** Performs a cooperative task switch by suspending the execution of the current activity and resuming the execution of any other activity that is ready to continue. *)
(** This procedure is called by the compiler whenever it detects that the time quantum of the current activity has expired. *)
PROCEDURE Switch-;

                PROCEDURE &Init*;
                BEGIN
                        last.ch := 0X; (*last.key := 0X;*) last.flags := {0..31};
                        Objects.InstallHandler(SELF.HandleInterrupt, Machine.IRQ0+1)
                END Init;

      
PROCEDURE VisitWhileStatement(x: SyntaxTree.WhileStatement);
VAR start: Label; true,false: Label;
BEGIN
  IF Trace THEN TraceEnter("VisitWhileStatement") END;
  IF cooperativeSwitches THEN EmitCooperativeSwitch END;
  start := NewLabel();
  true := NewLabel();
  false := NewLabel();
  SetLabel(start);
  Condition(x.condition,true,false);
  SetLabel(true);
  StatementSequence(x.statements);
  IF cooperativeSwitches THEN EmitCooperativeSwitch END;
  BrL(start);
  SetLabel(false);
  IF Trace THEN TraceExit("VisitWhileStatement") END;
END VisitWhileStatement;