public SNESSystem(ICPU cpu, IRenderer renderer, IROM rom, IPPU ppu, IAPU apu, IAudioHandler audioHandler)
 {
     CPU          = cpu;
     Renderer     = renderer;
     AudioHandler = audioHandler;
     ROM          = rom;
     rom?.SetSystem(this);
     PPU = ppu;
     PPU?.SetSystem(this);
     APU = apu;
     CPU?.SetSystem(this);
 }