Skeleton of Dart Nes Emulator

main.dart

import 'dart:async';

class Clock {
  Future<Null> _tick;
  final Duration _clockSpeed;

  Clock(this._clockSpeed);

  Future<Null> get nextTick => _tick;

  void start() {
    _tick = new Future.delayed(_clockSpeed).then((_) {
      start();
    });
  }
}

class CentralProcessingUnit {
  final Clock clock;

  CentralProcessingUnit(this.clock);

  Future<Null> start() async {
    print('cpu 1');
    await clock.nextTick;
    print('cpu 2');
    await clock.nextTick;
    print('cpu 3');
    await clock.nextTick;
    print('cpu 4');
    await clock.nextTick;
    print('cpu 5');
    await clock.nextTick;
    print('cpu 6');
    await clock.nextTick;
    print('cpu 7');
    await clock.nextTick;
    print('cpu 8');
    await clock.nextTick;
    print('cpu 9');
    await clock.nextTick;
    print('cpu 10');
  }
}

class PictureProcessingUnit {
  final Clock clock;

  PictureProcessingUnit(this.clock);

  Future<Null> start() async {
    print('screen 1');
    await clock.nextTick;
    print('screen 2');
    await clock.nextTick;
    print('screen 3');
    await clock.nextTick;
    print('screen 4');
    await clock.nextTick;
    print('screen 5');
    await clock.nextTick;
    print('screen 6');
    await clock.nextTick;
    print('screen 7');
    await clock.nextTick;
    print('screen 8');
    await clock.nextTick;
    print('screen 9');
    await clock.nextTick;
    print('screen 10');
  }
}

Future<Null> main() async {
  var clock = new Clock(const Duration(seconds: 1));
  var cpu = new CentralProcessingUnit(clock);
  var ppu = new PictureProcessingUnit(clock);
  clock.start();
  cpu.start();
  ppu.start();
}