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

/**
 * A 16-Bit register called "A Register". 
 * If load[t-1]=1 then out[t] = in[t-1]
 * else out does not change (out[t] = out[t-1])
 *
 * This built-in chip implementation has the side effect of 
 * providing a GUI representation of a 16-bit register
 * called "A register" (typically used to store an address).
 */

CHIP ARegister {

    IN  in[16], load;
    OUT out[16];

    BUILTIN ARegister;
    CLOCKED in, load;
}