#homebrew #playstation #no-std

nightly no-std psx

Library for developing homebrew for the Sony PlayStation 1

2 releases

0.1.6 Jun 7, 2022
0.1.5 Jun 4, 2022
0.1.4 May 4, 2022

#385 in Embedded development

MIT license

180KB
4K SLoC

psx-sdk-rs

This is a basic SDK to run custom Rust code on a PlayStation 1. It works with Rust nightly version equal to or later than 2022-06-03. Use rustup to install the rust toolchain as follows.

rustup update nightly
rustup component add rust-src --toolchain nightly

Installing cargo-psx

cargo-psx is an optional wrapper for cargo that sets some commonly required flags and arguments and copies the target JSON to the crate's target directory. Basically this lets you just run cargo psx run instead of

RUSTFLAGS="-Ccodegen-units=1                               \
    -Clink-arg=-Tpsexe.ld -Clink-arg=--oformat=binary"     \
    cargo run +psx -Zbuild-std=core                        \
    -Zbuild-std-features=compiler-builtins-mem             \
    --target /path/to/mipsel-sony-psx.json

which has the minimum number of flags required to create and run an exe.

To install:

cargo install cargo-psx

To uninstall:

cargo uninstall cargo-psx

For more options:

cargo psx --help

Usage

The examples directory has some demos which have been tested with the SCPH7001 NA BIOS in mednafen, pcsx-redux and/or duckstation. Other BIOS versions/regions may work but have not been tested. To try out a demo first check that you have the emulator in examples/$DEMO/.cargo/config.toml installed, then run cargo psx run from its directory.

To manually select the executable in your emulator, first build with cargo psx build then open the .exe in /path/to/crate/target/mipsel-sony-psx/release/. To use cargo psx run with other emulators change the runner for the mipsel-sony-psx target. To package the executable into an ISO (e.g. to use the CD-ROM filesystem) use mkpsxiso or similar.

Mednafen

Mednafen tends to just work with the following .cargo/config.toml. Getting stdout may require setting psx.dbg_level in mednafen.cfg to at least 2. When loading ISOs there doesn't seem to be a fastboot (skip BIOS) option, so ISOs must be licensed properly since the BIOS validates some checksums.

[target.mipsel-sony-psx]
runner = "mednafen"

PCSX-Redux

PCSX-Redux works with the following .cargo/config.toml. Note that -loadexe must be the last option since cargo psx run passes the executable filename at the end. See this page for more command line options.

[target.mipsel-sony-psx]
runner = ["pcsx-redux", "-stdout", "-run", "-loadexe"]

To run an ISO from the command line use pcsx-redux -stdout -run -iso $ISO_FILENAME.

DuckStation

DuckStation works and is extremely useful for debugging, but it doesn't work with cargo psx run. The issue is that the command passes the runner a relative path to the executable, but DuckStation only accepts absolute paths on the command line. To use DuckStation, build with cargo psx build then open the executable manually. To run an ISO use duckstation-qt -fastboot /full/path/to/$ISO_FILENAME.

Program template

To create a new program just use cargo init and add psx = "*" or psx = { path = "/path/to/psx/crate" } to Cargo.toml under [dependencies]. Then replace src/main.rs with the following template

#![no_std]
#![no_main]

// This can be any import from the `psx` crate
// but there must be at least one.
use psx;

#[no_mangle]
fn main() {
}

no_std is required to link the core crate instead of std. no_main tells rustc to make no assumption about the program's entry point. The attribute on main is required since the entry point defined in the psx crate expects to call an unmangled function. The main function should not return, but the return type can be either omitted (i.e. ()) or !.

Documentation

See docs.rs for documentation. To regenerate documentation for the latest version of psx:

cd psx
cargo doc --target mipsel-unknown-linux-gnu

Then open target/mipsel-unknown-linux-gnu/doc/psx/index.html in a browser.

For documentation on PlayStation internals see the nocash specs.

Testing

Use the following to run the tests in the psx crate.

cd psx/
cargo psx test

Dependencies