chips/FullAdder.hdl


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

// 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/02/FullAdder.hdl

/**
 * Computes the sum of three bits.
 */

CHIP FullAdder {
    IN a, b, c;  // 1-bit inputs
    OUT sum,     // Right bit of a + b + c
        carry;   // Left bit of a + b + c

    PARTS:
    // Put you code here:
    HalfAdder (a=a, b=b, sum=sum1, carry=carry1);
    HalfAdder (a=sum1, b=c, sum=sum, carry=carry2);
    Or (a=carry1, b=carry2, out=carry);
}