ngdevkit, open source development for Neo-Geo

Overview

ngdevkit is a C software development kit for the Neo-Geo AES or MVS hardware. It includes:

• A toolchain for cross compiling to m68k, based on GCC 5.5 and newlib for the C standard library.

• C headers for accessing the hardware. The headers follow the naming convention found at the NeoGeo Development Wiki.

• Helpers for declaring ROM information (name, DIP, interrupt handlers...)

• A C and ASM cross-compiler for the z80 (SDCC 4.2), for developing your music and sound driver.

• An open source replacement BIOS for testing your ROMs under you favorite emulator.

• Tools for managing graphics for fix and sprite ROM.

• Support for source-level debugging with GDB!

• A modified version of the emulator GnGeo, with support for libretro's GLSL shaders and remote debugging!

• A simple scanline pixel shader for a nice retro look!

How to use the devkit

Installing pre-built binary packages

There are nightly packages available for Linux, macOS and Windows, so you get the most up-to-date devkit without recompiling the entire toolchain any time there is an update in git.

Linux

If you are running an Ubuntu or Debian distribution, you can install pre-built debian packages from the ngdevkit PPA, as well as a couple of dependencies for the examples ROMs:

add-apt-repository -y ppa:dciabrin/ngdevkit
apt-get update
apt-get install ngdevkit ngdevkit-gngeo
# the remaining packages are only requred for the examples
apt-get install pkg-config autoconf zip imagemagick sox libsox-fmt-mp3

If you are running a Fedora distribution, pre-built packages are available in COPR, and can be installed with the following commands:

dnf copr enable dciabrin/ngdevkit
dnf install ngdevkit ngdevkit-gngeo
# the remaining packages are only requred for the examples
dnf install install pkg-config autoconf zip ImageMagick sox

macOS

If you are running on macOS, you can install brew packages, available in the ngdevkit tap:

# If you haven't done it yet, make sure XCode is installed first
sudo xcode-select --install
brew tap dciabrin/ngdevkit
brew install ngdevkit ngdevkit-gngeo
# make sure you use brew's python3 in your shell
export PATH=/usr/local/opt/python3/bin:$PATH
pip3 install pygame
# the remaining packages are only required for the examples
brew install pkg-config autoconf automake zip imagemagick sox

Some macOS versions are not currently pre-built (macOS 11 Intel and M1), as our CI provider doesn't currently offer free hosted agents yet, so it might take some time to install the packages.

Windows

You can run ngdevkit natively on Windows, via the MSYS2 environment. Pre-built ngdevkit packages are available for the ucrt64 subsystem of MSYS2. To use them, start a MSYS2 shell for ucrt64, and configure the pacman repository as follows:

MSYSTEM=UCRT64 /usr/bin/bash -l
echo -e "\n[ngdevkit]\nSigLevel = Optional TrustAll\nServer = https://dciabrin.net/msys2-ngdevkit/\$arch" >> /etc/pacman.conf

# install pacboy with `pacman -S pactoys` if necessary
pacboy -Sy
pacboy -S ngdevkit:u ngdevkit-gngeo:u
# the remaining packages are only required for the examples
pacboy -S autoconf automake make zip imagemagick:u sox:u

An old version of ngdevkit supported Windows 10 via WSL, but it is now deprecated in favour of the native MSYS2 environment. Likewise, we no longer build nightly packages for MSYS2's mingw64 subsystem, ucrt64 is the only supported subsystem for ngdevkit.

Build the included examples

The devkit comes with a series of examples to demonstrate how to use the compiler and tools. Once ngdevkit packages are installed, you can clone the ngdevkit-examples repository:

git clone --recursive https://github.com/dciabrin/ngdevkit-examples examples

And build all the examples with the following commands if you are running on Linux or Windows/MSYS2:

cd examples
autoreconf -iv
./configure
make

For macOS, make sure you use brew's python3 and gmake:

cd examples
export PATH=/usr/local/opt/python3/bin:$PATH
autoreconf -iv
./configure
gmake

Running the emulator

Once you have built the examples, go into a subdirectory to test the compiled example and run GnGeo from the makefile:

cd examples/01-helloworld
make gngeo
# or run "make gngeo-fullscreen" for a more immersive test

If you are running a recent macOS, System Integrity Protection may prevent you from running GnGeo from make, so you may need to run it from your terminal:

eval $(gmake -n gngeo)

Debugging your programs

The devkit uses a modified version of GnGeo which supports remote debugging via GDB. In order to use that feature on the example ROM, you first need to start the emulator in debugger mode:

cd examples/01-helloworld
# example ROM is named puzzledp
ngdevkit-gngeo -i rom puzzledp -D

With argument -D, the emulator waits for a connection from a GDB client on port 2159 of localhost.

Then, run GDB with the original ELF file as a target instead of the final ROM file:

cd examples/01-helloworld
m68k-neogeo-elf-gdb rom.elf

The ELF file contains all the necessary data for the debugger, including functions, variables and source-level line information.

Once GDB is started, connect to the emulator to start the the debugging session. For example:

(gdb) target remote :2159
Remote debugging using :2159
0x00c04300 in ?? ()
(gdb) b main.c:52
Breakpoint 1 at 0x57a: file main.c, line 52.
(gdb) c

Building the devkit from sources

If you want to build from source, this repository is the main entry point: it provides the necessary tools, headers, link scripts and open source BIOS to build your homebrew roms. The rest of the devkit is split into separate git repositories that are automatically cloned at build time:

• ngdevkit-toolchain provides the GNU toolchain, newlib, SDCC and GDB.

• gngeo and emudbg provide a custom GnGeo with support for GLSL shaders and remote gdb debugging.

• ngdevkit-examples shows how to use the devkit and how to program the Neo Geo hardware. It comes with a GnGeo configuration to run your roms with a "CRT scanline" pixel shader.

There are dedicated instructions to build ngdevkit for Linux, macOS or Windows.

History

This work started a long time ago (2002!) and was originally called neogeodev on sourceforge.net. Since then, a community has emerged at NeoGeo Development Wiki, and it is a real treasure trove for Neo-Geo development. Coincidentally, they are hosted at neogeodev.org, so I decided to revive my original project on github as ngdevkit :P

Acknowledgments

Thanks to Charles Doty for his Chaos demo, this is how I learned about booting the console, and fiddling with sprites!

Thanks to Mathieu Peponas for GnGeo and its effective integrated debugger. Thanks to the contributors of the mame project for such a great emulator.

A big thank you goes to Furrtek, ElBarto, Razoola...and all the NeoGeo Development Wiki at large. It is an amazing collection of information, with tons of hardware details and links to other Neo-Geo homebrew productions!

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this program. If not, see http://www.gnu.org/licenses/.