nand2tetris/projects/05/Computer.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/05/Computer.hdl

/**
 * The HACK computer, including CPU, ROM and RAM.
 * When reset is 0, the program stored in the computer's ROM executes.
 * When reset is 1, the execution of the program restarts.
 * Thus, to start a program's execution, reset must be pushed "up" (1)
 * and "down" (0). From this point onward the user is at the mercy of
 * the software. In particular, depending on the program's code, the
 * screen may show some output and the user may be able to interact
 * with the computer via the keyboard.
 */

CHIP Computer {

    IN reset;

    PARTS:

    CPU(
      inM=RAMRead,
      instruction=instruction,
      reset=reset,
      outM=RAMWrite,
      writeM=writeM,
      addressM=RAMReadWriteAddress,
      pc=instructionPointer);

    ROM32K(
      address=instructionPointer,
      out=instruction
    );

    Memory(in=RAMWrite,
           load=writeM,
           address=RAMReadWriteAddress,
           out=RAMRead);
}