一位全加器可由两个一位半加器与一个或门构成，该设计利用层次结构描述法，首先设计半加器电路，将其打包为半加器模块；然后在顶层调用半加器模块组成全加器电路-A full adder can be two a half-adder and an OR gate structure, the design is the use of hierarchical descr iption method, first of all the design half-adder circuit, be packa