Using two 4-bit registers R1 and R2, a 4-bit adder, a 2-to-1 multiplexer, and a 4-to-1 multiplexer,

Question:

Using two 4-bit registers R1 and R2, a 4-bit adder, a 2-to-1 multiplexer, and a 4-to-1 multiplexer, construct a circuit that implements the following operations under the control of the three multiplexer select inputs and the adder’s carry-in input:

R1 + R2 R1 - R2 R2 - R1 R1 1 - (R1 + 1) 0 -1