module onesctsm
title 'Ones-counting State Machine'
"ONESCTSM device 'P16V8R';

" Inputs and outputs
CLOCK, RESET, X, Y       pin 1, 2, 3, 4;
Z                        pin 13 istype 'com';
COUNT1..COUNT0           pin 14, 15 istype 'reg';

" Sets
COUNT = [COUNT1..COUNT0];

equations
COUNT.CLK = CLOCK;
WHEN RESET THEN COUNT := 0;
ELSE WHEN X & Y THEN COUNT := COUNT + 2;
ELSE WHEN X # Y THEN COUNT := COUNT + 1;
ELSE COUNT := COUNT;

Z = (COUNT == 0);

end onesctsm