// This file is part of the materials accompanying the book 
// "The Elements of Computing Systems" by Nisan and Schocken, 
// MIT Press. Book site: www.idc.ac.il/tecs
// File name: projects/03/b/RAM512.hdl

/**
 * Memory of 512 registers, each 16 bit-wide. Out holds the value
 * stored at the memory location specified by address. If load==1, then 
 * the in value is loaded into the memory location specified by address 
 * (the loaded value will be emitted to out from the next time step onward).
 */

CHIP RAM512 {
    IN in[16], load, address[9];
    OUT out[16];

    PARTS:
    DMux8Way(in=load,sel=address[0..2],a=a,b=b,c=c,d=d,e=e,f=f,g=g,h=h);
    RAM64(in=in,load=a,address=address[3..8],out=outa);
    RAM64(in=in,load=b,address=address[3..8],out=outb);
    RAM64(in=in,load=c,address=address[3..8],out=outc);
    RAM64(in=in,load=d,address=address[3..8],out=outd);
    RAM64(in=in,load=e,address=address[3..8],out=oute);
    RAM64(in=in,load=f,address=address[3..8],out=outf);
    RAM64(in=in,load=g,address=address[3..8],out=outg);
    RAM64(in=in,load=h,address=address[3..8],out=outh);
    Mux8Way16(a=outa,b=outb,c=outc,d=outd,e=oute,f=outf,g=outg,h=outh,sel=address[0..2],out=out);
}