midi-in / psn00bsdk

The most powerful open source SDK for the PS1.

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 100% freely. This SDK can be used for freeware, commercial, and open source homebrew projects.

The SDK is composed mainly of libraries (libpsn00b) and some utilities that provide a basic framework for developing software for the PlayStation hardware, the compiler is separate (GCC) and should be acquired from GNU. The library API is intentionally written to resemble the library API of the official libraries as closely as possible. This design decision is not only for familiarity reasons to experienced programmers, but also so that existing sample code and tutorials would still apply to this SDK, as well as making the process of porting over existing homebrew originally made with official SDKs easier with minimal modification, provided it doesn't use libgs.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, moreso 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 January 5, 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.

• 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

Because PSn00bSDK is updated semi-regularly due to this project being in a work-in-progress state, it is better to obtain this SDK from source and building it yourself in the long run. Pre-compiled packages for Debian and Msys2 are being planned however.

A precompiled copy of the GCC 7.4.0 toolchain for Windows is available in the PSn00bSDK page of Lameguy64's website ( http://lameguy64.net/?page=psn00bsdk ). This should make building PSn00bSDK under Windows a bit easier, as the GCC toolchain is quite difficult to compile correctly under Windows than it is on Linux and BSDs.

Building the SDK

You may set one of the following variables either with set/export or on the make command line, to specify various parameters in building PSn00bSDK and projects made with it as you see fit.

• GCC_VERSION specifies the GCC version number. This is only required for building the libc library. If not defined, the default value of 7.4.0 is used.
• PSN00BSDK_TC specifies the base directory of the GCC toolchain to build PSn00bSDK with, otherwise the makefile assumes you have the path to the toolchain binaries in one of your PATH directories. Alternatively, GCC_BASE can be specified in place of PSN00BSDK_TC. If not specified psn00bsdk-setup.mk assumes the toolchain is at C:\mipsel-unknown-elf in Win32 or /usr/local/mipsel-unknown-elf in Linux.
• PSN00BSDK_LIBS specifies the target directory you wish to install the compiled libpsn00b libraries to. If not defined, compiled libraries are consolidated to the libpsn00b directory and psn00bsdk-setup.mk assumes the SDK libraries are at ../psn00bsdk/libpsn00b.

Windows:

1. Download the following:

• MSys2 (32-bit or 64-bit version whichever you prefer)
• GCC 7.4.0 for mipsel-unknown-elf (download from Lameguy64's website at http://lameguy64.net?page=psn00bsdk if you rather not build it yourself)

2. Install MSys2, update packages (with pacman -Syu) then install the following packages:

• git
• make
• mingw-w64-i686-gcc (32-bit) or mingw-w64-x86_64-gcc (64-bit) You may need to close and reopen MSys2 for the PATH environment in the shell to update for MinGW.
• mingw-w64-i686-tinyxml2 (32-bit) or mingw-w64-x86_64-tinyxml2 (64-bit) Used by lzpack and smxlink.

3. Extract GCC 7.4.0 for mipsel-unknown-elf to the root of your C drive.
4. Edit mipsel-unknown-elf/mipsel-unknown-elf/lib/ldscripts/elf32elmip.x and append definitions to the .text definition as explained in toolchain.txt.
5. Add export PATH=$PATH:/c/mipsel-unknown-elf/bin to your .bash_profile file in MSys2. Test if mipsel-unknown-elf-gcc can be called from any directory in the terminal after reloading the MSys2 shell for the change to take effect.
6. Clone from PSn00bSDK source with git clone https://github.com/lameguy64/psn00bsdk Clone it in the root of your C drive or in any location you prefer.
7. Enter the tools directory in PSn00bSDK and run make to build all tools, then run make install to consolidate all tools to a single bin directory. Add this directory to your PATH variable by adding export=$PATH:<path to SDK>/tools/bin in your .bash_profile. Reload the MSys2 shell for the changes to take effect, then enter elf2x if the tools can be executed from any directory.
8. Enter libpsn00b directory and run make to build all libpsn00b libraries, then make install to consolidate the libraries to either the parent directory or the directory specified by PSN00BSDK_LIBS.
9. Compile the example programs by running make from the examples directory to test the SDK.

If you prefer to do things in the Command Prompt, you can add the paths c:\msys64\usr\bin, c:\msys64\mingw64\bin (mingw32 for 32-bit), c:\mipsel-unknown-elf\bin and c:\psn00bsdk\tools\bin (paths may vary depending on where you've installed/extracted them) to your system's PATH environment variable. This way, you can invoke make and compile programs with PSn00bSDK within the Command Prompt.

Linux and Unix-likes:

1. Install gcc, make, texinfo, git and development packages of mpfr, mpc, gmp, isl and tinyxml2 libraries for your distro.
2. Build and install the GNU GCC toolchain targeting mipsel-unknown-elf (see toolchain.txt for details). Export a variable named PSN00BSDK_TC containing a path to the installed toolchain's base directory if you've installed the toolchain in a location other than /usr/local. Also export a GCC_VERSION variable if you're using a version of GCC other than 7.4.0.
3. Clone from PSn00bSDK source with git clone https://github.com/lameguy64/psn00bsdk
4. Enter tools directory and run make, then make install to consolidate the tools to the bin directory. Add this directory to your PATH variable and make sure elf2x and other tools are accessible from any directory.
5. Enter the libpsn00b directory and run make. Then, run make install to consolidate the libraries to the libpsn00b parent directory, or the directory specified by PSN00BSDK_LIBS.
6. Compile the example programs by running make from the examples directory to test the SDK.

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 at http://lameguy64.net/tutorials/pstutorials/ 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.

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

• Support for MDEC.

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

Usage terms

PSn00bSDK falls under the terms and conditions of the Mozilla Public License. A quick summary of this license is that PSn00bSDK can be used freely in both free and open source projects and commercial closed source projects as projects using PSn00bSDK does not necessarily have to follow the MPL as well.

If modifications to the SDK were made as part of the development of such projects that enhance its functionality, such changes must be contributed back in return.

Homebrew made with PSn00bSDK may not be released under 'annoyingmous'. Although there's nothing that would enforce it, this term may as well be ignored despite it annoying this SDK's author.

Credits

Main developer:

• Lameguy64

Honorable mentions:

• ijacquez - helpful suggestions for getting C++ working.
• NicolasNoble - 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 (http://problemkaputt.de/psx-spx.htm)
• Tails92's PSXSDK project (during PSn00bSDK's infancy).