MODULE check0s;
(*---------------------------------------------------------
File name: check0s.pm
Author: AG
Date: 6/8/05 

Problem: Checks if the chain is full of 0s between LeftLimit and RightLimit.
LeftLimit = 3
RightLimit = 19

Example of Execution 1:
	L1:  0  1  2  2  0  0  1  2  1  1  1  2  1  1  0
	Res: FALSE
	
Example of Execution 2:
	L1:  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0
	Res: TRUE

Cycles:
1 Test + 2 assignments.
*)
(*----------------------------------------------------------
		CONFIGURATION
----------------------------------------------------------*)
CONST  MAXCELLS=1024; (* MAXCELLS cells in one line *)

CONFIGURATION chain[0..(MAXCELLS - 1)];
CONNECTION
		left: chain [i] -> chain[(i-1) MOD MAXCELLS];
		right: chain[i] -> chain[(i+1) MOD MAXCELLS];
(*----------------------------------------------------------
		VARIABLES
----------------------------------------------------------*)
VAR 
		L1: chain OF INTEGER;
		LeftLimit, RightLimit: INTEGER;
		Res: BOOLEAN;
(*----------------------------------------------------------
		MAIN
----------------------------------------------------------*)
BEGIN
	(* Initialize data *)
	L1 := RandomInt(chain) MOD 3;
	(* L1 := 0; *)
	
	(*define limits *)
	RightLimit:= 19;
	LeftLimit := 3;
	Res:= TRUE;		(* Assume it is true *)

	IF LeftLimit < ID(chain) < RightLimit THEN (* select cells *)
		IF L1 # 0 THEN		(* If we find anything that is not a '0' *)
			Res:= FALSE;	(* then we change it to false *)
		END; (* IF *)
		
		(*printing *)
		WriteString("L1: "); WriteInt(L1, 2); WriteLn;
		WriteString("Res: "); WriteBool(Res,0); WriteLn; 
	END; (* IF *)
END check0s.