A half adder is a circuit that can add two bits at a time to produce a sum and a carry. Design a half adder using only two gates. Write an entity-architecture pair to implement the half adder. Now write an entity-architecture pair to implement a full adder using two instances of your half adder and an OR gate. Use the port definitions specified below: For the half adder: port (a, b: in bit; s, c: out bit); For the full adder: port (a, b, cin: in bit; sum, cout: out bit); Simulate your code and test it using the following inputs: a b cin = 001, 011, 111, 110, 100