Repeat Problem 3-59 by using three-input, one-output circuits, one for each of the four bits. The four circuits are connected together in cascade by carrylike signals. One of the inputs to each cell is a carry input, and the single output is a carry output.

Problem 3-59

Design a combinational circuit that compares two 4-bit unsigned numbers A and B to see whether B is greater than A. The circuit has one output X, so that X = 1 if A < B and X = 0 if A ≥ B.