MODULE checksort;
(*---------------------------------------------------------
File name: checksort.pm
Author: AG
Date: 6/06/05 

Problem: This program checks if a line is sorted.

Example of Execution 1:
	L1: 1  2  3 10  5  6  7  8  9 10 11 12 13 14 15
	L2temp: 0  1  1  7 -5  1  1  1  1  1  1  1  1  1  1
	Res:FALSE

Example of Execution 2:
	L1: 1  2  3  4  5  6  7  8  9 10 11 12 13 14 15
	L2temp: 0  1  1  1  1  1  1  1  1  1  1  1  1  1  1
	Res:TRUE

Cycles:
2 assignments + 2 tests + 1 ID + 1 shift + 1 substraction.
*)
(*----------------------------------------------------------
		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, L2temp: chain OF INTEGER;
		RightLimit:  INTEGER;
		Res: BOOLEAN;
(*----------------------------------------------------------
		MAIN
----------------------------------------------------------*)
BEGIN
	(* initialize data  change the value of L1 to any line *)
	L1 := ID(chain);
	RightLimit := 16;
	(* L1<<4>>:= 10;  <- makes it false*)
	
	IF ID(chain) > 1 THEN
		L2temp := RECEIVE.right(L1);
		L2temp := L1 - L2temp;
	END; (* IF *)
	
	Res := TRUE;
	IF L2temp < 0 THEN
		Res := FALSE;
	END; (* IF *)
	
	(* printing *)
	IF ID(chain) < RightLimit THEN
		WriteString("L1:" ); WriteInt(L1, 2); WriteLn;
		WriteString("L2temp:" ); WriteInt(L2temp, 2); WriteLn;
		WriteString("Res:" ); WriteBool(Res, 2); WriteLn;
	END; (* IF *)
END checksort.