You need to design a circuit that implements the functions in the following table:

S0 and S1 are 1-bit control inputs to select the function of the circuit. Inputs A and B are 4-bit numbers in 2s complement form. The output is also a 4-bit number in 2s complement form. You are allowed to use only one TTL 7483 4-bit adder to implement all the functions. But any number of other components (except the adder) can be used. HINT: Design a combinational logic circuit to modify the input B and the carry input of the adder depending on the control inputs S0 and S1.

Side Note:

I found the following solutions online, however, I unable to understand how they were able to reach these solutions because there were no real explanations. I would really appreciate a detailed solution as to how they reached these conclusions, thank you!

SO S1 Function 01 A- B 1 1 A1