// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/01/DMux8Way.hdl

/**
 * 8-way demultiplexor:
 * {a, b, c, d, e, f, g, h} = {in, 0, 0, 0, 0, 0, 0, 0} if sel == 000
 *                            {0, in, 0, 0, 0, 0, 0, 0} if sel == 001
 *                            etc.
 *                            {0, 0, 0, 0, 0, 0, 0, in} if sel == 111
 */

// COST = 37 + 8*8 = 101
CHIP DMux8Way {
    IN in, sel[3];
    OUT a, b, c, d, e, f, g, h;

    PARTS:

    // This makes our "repeated building block" - which we repeat twice
    // Same as how we do it in DMux4Way
    DMux4Way(in=in, sel[0]=sel[0], sel[1]=sel[1], a=w, b=x, c=y, d=z);


    // If sel[2] is 1:
    // set a,b,c,d to 0
    // else set a,b,c,d to w,x,y,z
    Mux(a=w, b=false, sel=sel[2], out=a);
    Mux(a=x, b=false, sel=sel[2], out=b);
    Mux(a=y, b=false, sel=sel[2], out=c);
    Mux(a=z, b=false, sel=sel[2], out=d);

    // If sel[2] is 0:
    // set e,f,g,h to 0
    // else set e,f,g,h to w,x,y,z
    Mux(a=false, b=w, sel=sel[2], out=e);
    Mux(a=false, b=x, sel=sel[2], out=f);
    Mux(a=false, b=y, sel=sel[2], out=g);
    Mux(a=false, b=z, sel=sel[2], out=h);
}