// 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/05/Memory.hdl

/**
 * The complete address space of the Hack computer's memory,
 * including RAM and memory-mapped I/O. 
 * The chip facilitates read and write operations, as follows:
 *     Read:  out(t) = Memory[address(t)](t)
 *     Write: if load(t-1) then Memory[address(t-1)](t) = in(t-1)
 * In words: the chip always outputs the value stored at the memory 
 * location specified by address. If load==1, the in value is loaded 
 * into the memory location specified by address. This value becomes 
 * available through the out output from the next time step onward.
 * Address space rules:
 * Only the upper 16K+8K+1 words of the Memory chip are used. 
 * Access to address>0x6000 is invalid. Access to any address in 
 * the range 0x4000-0x5FFF results in accessing the screen memory 
 * map. Access to address 0x6000 results in accessing the keyboard 
 * memory map. The behavior in these addresses is described in the 
 * Screen and Keyboard chip specifications given in the book.
 */

CHIP Memory {
    IN in[16], load, address[15];
    OUT out[16];

    PARTS:
        // Put your code here:
        //p334: 
        //addressが000 0000 0000 0000 - 011 1111 1111 1111はRAMメモリ
        //addressが100 0000 0000 0000 - 101 1111 1111 1111はスクリーン
        //addressが110 0000 0000 0000はキーボード
        Not(in=address[14], out=n14);
        And(a=load, b=n14, out=loadr);
        Not(in=address[13], out=n13);
        And(a=load, b=address[14], out=and14);
        And(a=and14, b=n13, out=loads);
        
        RAM16K(in[0..15]=in[0..15], load=loadr, address[0..13]=address[0..13], out[0..15]=outr);
        Screen(in[0..15]=in[0..15], load=loads, address[0..12]=address[0..12], out[0..15]=outs);
        Keyboard(out[0..15]=outk);
        
        //if address[13]=0のときoutrを出力
        //else if address[12]=0のときoutsを出力
        //else outkを出力
        Mux4Way16(a[0..15]=outr, b[0..15]=outr, c[0..15]=outs, d[0..15]=outk, sel[0..1]=address[13..14], out[0..15]=out[0..15]);
        
        
}