Starting Point

For this worksheet, we need a 4-bit adder that can also perform subtraction. The adder has the following characteristics:

• Inputs a and b are 4 bits wide.

• The input add/sub (1 bit) selects addition with 0 and subtraction with 1.

• The 4-bit output s shows the result of the operation.

• The Cout output indicates overflow and is directly connected to the Cout of the 4-bit adder from CircuitVerse. In subtraction, the value is not negated.