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https://github.com/liarprincess/swift-plays-pokemon

Game Boy emulator written in Swift.
https://github.com/liarprincess/swift-plays-pokemon

gameboy gameboy-emulator swift

Last synced: 15 days ago
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Game Boy emulator written in Swift.

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README 

        
# Swift plays Pokemon



Game Boy emulator written in Swift.



## Features



* Instruction accurate - while it is not *per-cycle* accurate, it will run most of the games without any problems.

* Supports following cartridge types (MBC stands for [memory bank controller](http://bgb.bircd.org/pandocs.htm#memorybankcontrollers)):

  - no MBC - for example: *Tetris*

  - MBC1 - for example: *Legend of Zelda - The Links Awakening* and *Kirby's Dream Land*

  - MBC3 - for example: *Pokemon Red*

* blargg tests:

  * ✅ cpu\_instrs

  * ✅  instr\_timing

* Save/load emulator state to file

* Safe from *Meltdown* and *Spectre*



Not supported:



* Audio

* `stop` instruction (`0x10` from unprefixed instruction set) - not really used



## Source map



- `Swift plays Pokemon.xcodeproj` - XCode project file. Use this instead of Swift Package Manager (SPM does not support Metal shaders that we use inside `GameBoyMac`). Although, if your code depends only on `GameBoyKit` framework, then SPM is *ok*.



- [Sources](Sources)



  - [GameBoyMac](Sources/GameBoyMac) - Mac app that runs the emulator. You can use `--rom` argument to specify ROM (or just give it as a last argument). It uses `GameBoyKit` framework.



  - [GameBoyKit](Sources/GameBoyKit) - Main implementation of GameBoy logic. It contains `GameBoy` class alongside many other useful things like: `Cpu`, `Lcd` and `Debugger`.



  - [Code generation](Sources/Code%20generation) - Code generation executable, based on [lmmendes/game-boy-opcodes](https://github.com/lmmendes/game-boy-opcodes).



- [Tests](Tests)



  - [GameBoyKitTests](Tests/GameBoyKitTests) - Unit tests. Most notably it includes basic tests for every `CPU` instruction.



  - [GameBoyKitROMTests](Tests/GameBoyKitROMTests) - Tiny app that will run ROM based tests, for example [Blargg test ROMs](https://gbdev.gg8.se/files/roms/blargg-gb-tests/). Please note that this an app, not an XCode test target!



- [ROMs](ROMs) - directory that holds games/test ROMs.



  - [Tests - Blargg](ROMs/Tests%20-%20Blargg) - directory to store [Blargg test ROMs](https://gbdev.gg8.se/files/roms/blargg-gb-tests/).



## Screenshots



![Tetris](/Images/Tetris.png)

![Pokemon Red](/Images/Pokemon%20Red.png)

![Legend of Zelda - The Links Awakening](/Images/Legend%20of%20Zelda.png)

![Super Mario Land](/Images/Super%20Mario%20Land.png)

![Bomberman](/Images/Bomberman.png)

![Kirby's Dream Land](/Images/Kirbys%20Dream%20Land.png)



## Keys



For the `GameBoyMac` target (emulator executable) following key map is used:



| Action | Key |

| --- | --- |

| DPAD-UP | ↑ |

| DPAD-DOWN | ↓ |

| DPAD-LEFT | ← |

| DPAD-RIGHT | → |

| B | S |

| A | A |

| START | Q |

| SELECT | W |

| Save state | R |



## Tests



[Blargg's tests](http://gbdev.gg8.se/wiki/articles/Test_ROMs):



| Test | Result | Note |

| --- | --- | --- |

| cpu\_instrs | ✅ | Essential |

| instr\_timing | ✅ | Essential |

| cgb\_sound | ❌ | Audio is not implemented |

| dmg\_sound | ❌ | Audio is not implemented |

| interrupt\_time | ⚠️ | Not tested |

| mem\_timing | ⚠️ | Not tested |

| halt\_bug | ❌ | No game requires it |

| oam\_bug | ❌ | Game Boy bug that we do not implement, see [The Ultimate Game Boy Talk - 46m 30s](https://youtu.be/HyzD8pNlpwI?t=2791) |



## Links



- Game Boy internals:

  - [The Ultimate Game Boy Talk (33c3)

](https://www.youtube.com/watch?v=HyzD8pNlpwI) by Michael Steil - you have to watch it!

  - [bgb.bircd.org/pandocs](http://bgb.bircd.org/pandocs.htm) - most of the things are here

  - [gbdev.gg8.se](https://gbdev.gg8.se/wiki/articles/Main_Page) - pandocs alternative

  - [gbdev/awesome-gbdev](https://github.com/gbdev/awesome-gbdev) - curated list of awesome Game Boy (Color) Development resources, tools, docs, related projects and open-source ROMs

  - [pastraiser.com/gameboy_opcodes](https://www.pastraiser.com/cpu/gameboy/gameboy_opcodes.html) - instruction set

  - [reddit.com/Game Boy (vblank) interrupt confusion](https://www.reddit.com/r/EmuDev/comments/7rm8l2/game_boy_vblank_interrupt_confusion/) - interrupts are disabled until the instruction after EI

  - Audio - we do not have audio (yet), but this can be useful:

    - [gbdev.gg8.se/Gameboy sound hardware](https://gbdev.gg8.se/wiki/articles/Gameboy_sound_hardware)

    - [github.com/PumpMagic/ostrich](https://github.com/PumpMagic/ostrich) - Ostrich is a macOS media player app for playback of Game Boy Sound System files

    - [aselker.github.io/gameboy-sound-chip](https://aselker.github.io/gameboy-sound-chip/)

    - [reddit.com/GB Emulator - SDL2 Audio Queue weird behavior](https://www.reddit.com/r/EmuDev/comments/bnprrf/gb_emulator_sdl2_audio_queue_weird_behavior/)



- Other emulators (github links):

  - [Gekkio/mooneye-gb](https://github.com/Gekkio/mooneye-gb)

  - [mgba-emu/mgba](https://github.com/mgba-emu/mgba)

  - [binji/binjgb](https://github.com/binji/binjgb)

  - [torch2424/wasmboy](https://github.com/torch2424/wasmboy)

  - [Baekalfen/PyBoy](https://github.com/Baekalfen/PyBoy)

  - [simias/gb-rs](https://github.com/simias/gb-rs)



- Other:

  - [WebAssembly Is Fast: A Real-World Benchmark of WebAssembly vs. ES6 by Aaron Turner](https://medium.com/@torch2424/webassembly-is-fast-a-real-world-benchmark-of-webassembly-vs-es6-d85a23f8e193)



## License



“Swift plays Pokemon” is licensed under the Mozilla Public License 2.0.

See [LICENSE](LICENSE) file for more information.