changed random function, added CSP module

lang/m2/libm2/random.mod

@@ -1,11 +1,17 @@
 IMPLEMENTATION MODULE random;
 
-VAR	seed: CARDINAL;
+FROM Unix IMPORT getpid, time;
+TYPE index = [0..54];
+
+VAR	X: ARRAY index OF CARDINAL;
+	k, j: index;
 
 PROCEDURE Random(): CARDINAL;
 BEGIN
-	seed := seed * 77 + 153;
-	RETURN seed;
+	IF k+1 > 54 THEN k := 0; ELSE INC(k) END;
+	IF j+1 > 54 THEN j := 0; ELSE INC(j) END;
+	X[k] := X[k] + X[j];
+	RETURN X[k]
 END Random;
 
 PROCEDURE Uniform (lwb, upb: CARDINAL): CARDINAL;
@@ -15,5 +21,11 @@ BEGIN
 END Uniform;
 
 BEGIN
-	seed := 253B;
+	X[0] := time(NIL);
+	X[0] := CARDINAL(getpid()) * X[0];
+	FOR k := 1 TO 54 DO
+		X[k] := X[k-1] * 1297;
+	END;
+	k := 54;
+	j := 30;
 END random.