Rustation PlayStation Emulator

Rustation is a PlayStation emulator written entirely in Rust. This is not a standalone emulator, it's an emulator core that implements the libretro interface and can be used to play PlayStation game in a libretro frontend such as RetroArch.

A lot of this code is based on No$ PSX specifications and on Mednafen's PlayStation code as well as tests on the real hardware. The codebase aims to be readable and document what's known to be accurate, what's known to be inaccurate and what hasn't been tested yet.

Features

The emulator is still at a fairly early phase of development and still very glitchy and incomplete. Some notable features of this project are:

• Entirely software renderer that runs in a separate thread for better performance.

• Native support for 24bit rendering in software (actually at this point we don't even support dithered 16bpp like the original hardware, but it will be added eventually).

• Multithreaded CD cache implementation to avoid performance problems caused by high-latency storage.

• GDB-based debugger interface.

• Readable and well documented code, hopefully.

Build

You need to install a Rust build environment. Normally it's fairly straightforward, just follow the instructions on Rust's website.

Once that's done you can build an optimized build with:

cargo build --release

That should download all dependencies and output the core library in target/release/. On Linux that file is named librustation_ng_retro.so but the name may vary on other platforms.

Run

Once the core is compiled you can load it in your favourite libretro player to play your PlayStation games in BIN/CUE format. For instance using retroarch you can do:

retroarch -L librustation_ng_retro.so my_game.cue

Troubleshooting

Logs

If Rustation crashes, activate logging in your frontend to see what went wrong. Rustation tends to be fairly verbose so it should tell you explicitly what caused the failure.

To enable logging in RetroArch go to "Settings" -> "Logging". Set "Core Logging Level" to "0 (Debug)" to get all the messages.

Game formats

For now only BIN/CUE is supported. I'd like to support CHD eventually but for the time being I prefer to focus on the core of the emulator. Contributions on this front are more than welcome!

BIOS

As with most PlayStation emulators you'll need to have a proper PlayStation BIOS for the emulator to boot up correctly. Rustation will look for those BIOS files in the libretro "system directory" that you should be able to configure in your frontend.

As always look at Rustation's log messages to see whether it manages to find and load your BIOS. It should tell you which where it looks for the files, what he found and why it accepted or rejected any files. For instance when successfully loading a North American game I get the following output:

[libretro INFO] Loading "games/Crash Bandicoot (USA).cue"
[libretro INFO] Disc serial number: SCUS-94900
[libretro INFO] Detected disc region: NorthAmerica

This tells you that the game image has been successfully loaded and its serial number and region have been detected.

[INFO] [Environ]: SYSTEM_DIRECTORY: "system".
[libretro INFO] Looking for a suitable BIOS in "system"

That tells you in which directory we are looking for the BIOS file.

[libretro DEBUG] Ignoring "system/dmg_boot.bin": bad size
[libretro DEBUG] Ignoring "system/gbc_bios.bin": bad size
[libretro INFO] Found BIOS DB entry for "system/scph5500.bin": Japan/v3.0
[libretro WARN] Ignoring "system/scph5500.bin": BadBios("\"/home/lionel/sync/roms/system/scph5500.bin\": rejected by predicate")
[libretro WARN] Ignoring "system/saturn_bios.bin": UnknownBios
[libretro INFO] Found BIOS DB entry for "system/scph5501.bin": NorthAmerica/v3.0
[libretro INFO] Using BIOS "system/scph5501.bin" (NorthAmerica/v3.0)

Here you see the emulator iterating on every file in the directory, attempting to find a suitable BIOS. If the file doesn't have the right size, isn't found in the internal BIOS database or isn't the right region for the game, it's rejected.