4-bit adder X97441

Design a circuit that performs the addition of two 4-bit numbers. The result (mod 16) must be represented in 4 bits also.
Specification

module adder4(a, b, sum); input [3:0] a, b; output [3:0] sum;

Hint You may want to use several instances of a 1-bit full adder.

Input

• a and b are the two 4-bit number.

Output

• sum is the 4-bit output representing (a+b)  mod  16.