jking323 / psn00bsdk

The most powerful open source SDK for the PS1 (as far as open source PS1 SDKs go). Not recommended for beginner use.

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written over the years would still apply to this SDK, as well as making the process of porting over existing homebrew originally made with official SDKs easier with minimal modificationn provided they do not depend on libgs.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 November 28, 2021

• Extensive GPU support with polygon, line and sprite primitives, high-speed DMA transfers for VRAM data 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. No BIOS ROM checks used.

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

• Flexible interrupt service routine 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. Should work without issue for loader/menu type programs as well.

• Complete Serial I/O support with SIOCONS driver for tty stdin/stdout console access. Hardware flow control also supported.

• BIOS controller functions for polling controller input work as intended thanks to proper handling of hardware interrupts. No crude manual polling of controllers in a main loop. BIOS memory card functions may also work, but not yet tested extensively.

• Full CD-ROM support via libpsxcd with data read, CD audio and XA audio playback support. Features built-in ISO9660 file system parser for locating and querying files and directories. Supports directories containing more than 30 files (classic ISO9660 only, no Rock Ridge or Joliet extensions) and also supports reading new sessions on a multi-session disc.

• Experimental support for compiling separate sections of an executable into shared library files (DLLs) and linking them dynamically at runtime, plus 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 to make 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

PSn00bSDK has switched to a CMake-based build and installation system. See installation.md for details.

Prebuilt SDK packages and versions of the GCC toolchain for Windows and Linux (DEB/RPM) are available through GitHub Actions. Stable releases haven't yet been published however, due to this project being in a work-in-progress state. It is still recommended to build the SDK from source for the time being.

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. The tutorials should still apply to PSn00bSDK.

To-do List

• psxspu: Plenty of work to be done. Hardware timer driven sound/music system may need to be implemented (an equivalent to the Ss* series of functions in libspu basically). Need to figure out the correct frequency table for playing sounds in musical note notation. Functions that make use of the SPU RAM interrupt feature to play or capture streamed audio should also be added.

• psxcd: Implement a command queue mechanism for the CD-ROM?

• libc: Improve the memory allocation framework with multiple allocators, GC and maybe helpers to manage swapping between main RAM and VRAM/SPU RAM.

• Support for MDEC, and tooling to transcode videos to .STR files (either reimplementing the container and compression format used by the Sony SDK, or a custom format with better compression).

• Pad and memory card libraries that don't use the BIOS routines.

Credits

Main developer/author/whatever:

• Lameguy64 (John "Lameguy" Wilbert Villamor)

Contributors:

• spicyjpeg: dynamic linker, CMake scripts, some docs and examples (system/dynlink, sound/spustream, io/pads, io/system573).

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.