问从一开始就设计HDL部分的逻辑: DM

EN

* {a,b,c,d} = {in,0,0,0} if sel==00
     *             {0,in,0,0} if sel==01
     *             {0,0,in,0} if sel==10
     *             {0,0,0,in} if sel==11
     */
    
    CHIP DMux4Way {
        IN in, sel[2];
        OUT a, b, c, d;
    
        PARTS:
        DMux(in=in,sel=sel[1],a=ao,b=bo);
        DMux(in=ao,sel=sel[0],a=a,b=b);
        DMux(in=bo,sel=sel[0],a=c,b=d);
}