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32 lines
910 B
Racket
32 lines
910 B
Racket
#lang br/demo/hdl
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// This file is part of www.nand2tetris.org
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// and the book "The Elements of Computing Systems"
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// by Nisan and Schocken, MIT Press.
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// File name: projects/01/DMux4Way.hdl
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/**
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* 4-way demultiplexor:
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* {a, b, c, d} = {in, 0, 0, 0} if sel == 00
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* {0, in, 0, 0} if sel == 01
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* {0, 0, in, 0} if sel == 10
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* {0, 0, 0, in} if sel == 11
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*/
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CHIP DMux4Way {
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// todo: how should sel subscripting work?
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IN in, sel[2];
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OUT a, b, c, d;
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PARTS:
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DMux(in=in, sel=sel[0], a=a, b=b);
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DMux(in=in, sel=sel[1], a=c, b=d);
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/*
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// the right answer: note that subscripting on right always means "read this bit";
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// subscripting on left means "write this bit"
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// build out assignment operator
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DMux(in=in, sel=sel[0], a=s0a, b=s0b);
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DMux(in=s0b, sel=sel[1], a=b, b=d);
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DMux(in=s0a, sel=sel[1], a=a, b=c);
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*/
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} |