用1位半减器构成一位全减器，之后再构成8位全减器。有三个组件：h_suber，一位半减器，f_suber，一位全减器，f_suber8，8位全减器。-With a half-wide device constituted by a browser, and then pose a 8-wide by browser. Has three components: h_suber, a half device, f_suber, a full-cut device, f_suber8, 8 are