模拟器是如何工作的?当我看到NES/SNES或C64模拟器时,我很震惊。

您是否必须通过解释特定的组装指令来模拟这些机器的处理器?还有什么?它们通常是如何设计的?

你能给那些对编写模拟器(特别是游戏系统)感兴趣的人一些建议吗?


当前回答

共享源设备模拟器包含PocketPC/智能手机模拟器的可构建源代码(需要Visual Studio,在Windows上运行)。我参与了二进制版本的V1和V2。

它解决了许多仿真问题: -从虚拟客户端到物理客户端再到虚拟主机的高效地址转换 - JIT编译客户代码 -模拟周边设备,如网络适配器、触摸屏和音频 - UI集成,主机键盘和鼠标 -保存/恢复状态,用于模拟从低功耗模式恢复

其他回答

还可以查看Darek Mihocka的Emulators.com,获得关于jit指令级优化的建议,以及许多关于构建高效模拟器的其他好东西。

在创建了我自己的80年代BBC微型计算机模拟器(类型VBeeb到谷歌)后,有许多事情要知道。

You're not emulating the real thing as such, that would be a replica. Instead, you're emulating State. A good example is a calculator, the real thing has buttons, screen, case etc. But to emulate a calculator you only need to emulate whether buttons are up or down, which segments of LCD are on, etc. Basically, a set of numbers representing all the possible combinations of things that can change in a calculator. You only need the interface of the emulator to appear and behave like the real thing. The more convincing this is the closer the emulation is. What goes on behind the scenes can be anything you like. But, for ease of writing an emulator, there is a mental mapping that happens between the real system, i.e. chips, displays, keyboards, circuit boards, and the abstract computer code. To emulate a computer system, it's easiest to break it up into smaller chunks and emulate those chunks individually. Then string the whole lot together for the finished product. Much like a set of black boxes with inputs and outputs, which lends itself beautifully to object oriented programming. You can further subdivide these chunks to make life easier.

Practically speaking, you're generally looking to write for speed and fidelity of emulation. This is because software on the target system will (may) run more slowly than the original hardware on the source system. That may constrain the choice of programming language, compilers, target system etc. Further to that you have to circumscribe what you're prepared to emulate, for example its not necessary to emulate the voltage state of transistors in a microprocessor, but its probably necessary to emulate the state of the register set of the microprocessor. Generally speaking the smaller the level of detail of emulation, the more fidelity you'll get to the original system. Finally, information for older systems may be incomplete or non-existent. So getting hold of original equipment is essential, or at least prising apart another good emulator that someone else has written!

我写过一篇关于用JavaScript模拟Chip-8系统的文章。

这是一个很好的开始,因为系统不是很复杂,但你仍然了解操作码、堆栈、寄存器等是如何工作的。

我将很快为NES写一篇更长的指南。

添加@Cody Brocious提供的答案 在虚拟化环境中,您正在向虚拟机模拟一个新系统(CPU、I/O等),我们可以看到以下类别的模拟器。

解释:bochs是解释器的一个例子,它是一个x86 PC模拟器,它把来自客户系统的每条指令翻译成另一组指令(主机ISA的指令)来产生预期的效果。是的,它非常慢,它不缓存任何东西,所以每条指令都经过相同的周期。

动态仿真器:Qemu是一个动态仿真器。它可以实时翻译客户指令,也可以缓存结果。最好的部分是直接在主机系统上执行尽可能多的指令,这样模拟就更快了。正如Cody所提到的,它将代码划分为块(一个单独的执行流)。

静态模拟器:据我所知,没有静态模拟器可以帮助虚拟化。

共享源设备模拟器包含PocketPC/智能手机模拟器的可构建源代码(需要Visual Studio,在Windows上运行)。我参与了二进制版本的V1和V2。

它解决了许多仿真问题: -从虚拟客户端到物理客户端再到虚拟主机的高效地址转换 - JIT编译客户代码 -模拟周边设备,如网络适配器、触摸屏和音频 - UI集成,主机键盘和鼠标 -保存/恢复状态,用于模拟从低功耗模式恢复