Please solve 8.43 question.

3.42 Section 8.5 presents a design for the serial adder. Derive a similar circuit that functions as a serial subtractor which produces the difference of operands A and B. (Hint: use the rule for finding 2's complements, in section 5.3.1, to generate the 2's complement of B.) Figure 8.39 Block diagram for the serial adder. G: carry-in =0 H: carry-in =1 Figure 8.40 State diagram for the serial adder FSM. 3.42 Section 8.5 presents a design for the serial adder. Derive a similar circuit that functions as a serial subtractor which produces the difference of operands A and B. (Hint: use the rule for finding 2's complements, in section 5.3.1, to generate the 2's complement of B.) Figure 8.39 Block diagram for the serial adder. G: carry-in =0 H: carry-in =1 Figure 8.40 State diagram for the serial adder FSM