PSn00bSDK

PSn00bSDK is a 100% free and open source SDK project for the original Sony PlayStation for developing homebrew applications and games for the console. This SDK may be used for freeware, commercial, and open source homebrew projects as far as what the SDK currently supports. Out of all the open source PS1 SDK projects that have come and gone from active development over the years, PSn00bSDK is arguably the most capable of them all.

Much of the SDK is merely just a set of libraries (libpsn00b) and some utilities for converting executables and data files to formats more usable on the target platform. The compiler used is just the standard GNU GCC toolchain compiled to target mipsel and has to be acquired separately. The library API was deliberately written to resemble the library API of the official libraries as closely as possible not only for familiarity reasons to experienced programmers but also so that existing sample code and tutorials that have been written over the years would still apply to this SDK, as well as making the process of porting over existing homebrew originally made with official SDKs easier with minimal modificationn provided they do not depend on libgs.

PSn00bSDK is currently a work in progress and cannot really be considered production ready, but what is currently implemented should be enough to produce some interesting homebrew with the SDK especially with its extensive support for the GPU and GTE hardware. There's no reason not to fully support hardware features of a target platform when said hardware features have been fully documented for years (nocash's PSX specs document in this case).

Most of libpsn00b is written mostly in MIPS assembly more so functions that interface with the hardware. Many of the standard C functions are implemented in custom MIPS assembly instead of equivalents found in the BIOS ROM, for both stability (the BIOS libc implementation of the PlayStation is actually buggy) and performance reasons.

Notable features

As of October 11, 2022:

• Extensive GPU support with lines, flat shaded or textured polygon and sprite primitives, high-speed DMA for VRAM transfers and ordering tables. All video modes for both NTSC and PAL standards also supported with fully adjustable display area and automatic video standard detection based on last GPU mode.

• Extensive GTE support with rotate, translate, perspective correction and lighting calculation fully supported through C and/or assembly GTE macros paired with high speed matrix and vector helper functions. All calculations performed in fixed point integer math, not a single float used.

• Flexible interrupt service subsystem with easy to use callback mechanism for simplified handling and hooking of hardware and DMA interrupts. No crude event handler hooks or kernel hacks providing great compatibility with HLE BIOS implementations and loader/menu type homebrew programs.

• BIOS controller functions for polling controller input work as intended thanks to proper handling of hardware interrupts. Optional limited support for manual polling.

• Complete Serial I/O support and console driver to redirect standard input and output to the serial port. Hardware flow control supported.

• Full CD-ROM support using libpsxcd featuring data reading, CD-DA and XA audio playback, a built-in ISO9660 file system parser with no file count limit and support for multi-session discs.

• MDEC support, lossy image decompression and video playback using libpsxpress (currently only bitstream versions 1 and 2 are supported).

• Preliminary limited support for Konami System 573 arcade hardware.

• Experimental support for dynamic linking at runtime, with support for function and variable introspection by loading a map file generated at build time.

• Uses Sony SDK library syntax for familiarity to experienced programmers and makes porting existing homebrew projects to PSn00bSDK easier.

• Works on real hardware and most popular emulators.

• Fully expandable and customizable to your heart's content.

Obtaining PSn00bSDK

Prebuilt PSn00bSDK packages for Windows and Linux are available on the releases page and include the libraries, a copy of the GCC MIPS toolchain, command-line tools, examples and documentation. CMake is not included and must be installed separately, either from its website or via MSys2 or your distro's package manager.

The releases can be installed by simply extracting the archives into any directory and adding the bin subfolder to the PATH environment variable. share/psn00bsdk/template contains a barebones example project that can be used as a starting point.

For more information on how to get started, or if you wish to build the SDK yourself from source instead, refer to installation.md.

Examples

There are a few examples and complete source code of n00bdemo included in the examples directory. More example programs may be added in the future and contributed example programs are welcome.

There's also Lameguy's PlayStation Programming Tutorial Series for learning how to program for the PlayStation. Much of the tutorials should apply to PSn00bSDK.

To-do List

• libpsxspu: Plenty of work to be done. Some kind of MIDI sequencer (similar to the one present in the official SDK) should be added at some point, along with a proper API for audio streaming.

• libpsxcd: Implement a command queue mechanism for the CD-ROM.

• libpsxpress: Add support for version 3 and IKI frame bitstreams.

• libc: Improve the memory allocation framework with multiple allocators, replace the string functions with optimized implementations and maybe add helpers to manage swapping between main RAM and VRAM/SPU RAM.

• Add a full controller and memory card API that does not depend on the BIOS controller driver, and possibly a library for interfacing to IDE/ATAPI drives to make development for arcade systems easier.

Credits

Main developer/author/whatever:

• Lameguy64 (John "Lameguy" Wilbert Villamor)

Contributors:

• spicyjpeg: dynamic linker, libpsxpress, CMake scripts, some docs and examples.
• Silent, G4Vi, Chromaryu: mkpsxiso and dumpsxiso (maintained as a separate repo).

Honorable mentions:

• ijacquez: helpful suggestions for getting C++ working.
• Nicolas Noble: his OpenBIOS project gave insight to how the BIOS works internally.

Helpful contributors can be found in the changelog.

References used:

• nocash's PlayStation specs document and Nicolas Noble's updated version.
• MIPS and System V ABI specs (for the dynamic linker).
• Tails92's PSXSDK project (during PSn00bSDK's infancy).

Additional references can be found in individual source files.