Introduction - If you have any usage issues, please Google them yourself
4 full adder by the three modules. First, the basic gate-level component instance references xor, and define the underlying half-adder module halfadder, then cite two examples of half-adder module halfadder and a base or gate element or combination of a full adder module fulladder, the last instance references 4 a one of the full adder module fulladder constitute four full adder top module