FullAdder.hdl

// 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:
    HalfAdder( a = a, b = b, sum = sumI, carry = carryI);
    HalfAdder( a = sumI, b = c, sum = sum, carry = carryII);
    Or(a = carryI, b = carryII, out = carry);
}