ngdevkit, open source development for Neo-Geo

ngdevkit is a C/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 3.7), 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

If you're running an Ubuntu or Debian distribution, you can install pre-built nightly binary packages, so you get the most up-to-date devkit without recompiling the entire toolchain at every update.

You need to enable the ngdevkit PPA and install a couple of dependencies:

add-apt-repository -y ppa:dciabrin/ngdevkit
# if you're running Ubuntu 18.04 (Bionic), add the following ppa for PyGame
# add-apt-repository -y ppa:thopiekar/pygame
apt-get update
apt-get install ngdevkit ngdevkit-gngeo
apt-get install pkg-config autoconf zip imagemagick sox libsox-fmt-mp3

If you're running on Windows 10, you can also use those pre-built deb binaries with WSL. It is complemented by a pre-built native version of GnGeo. Details on how to install and use them are available in a dedicated README.

If you're running on macOS, you can install pre-built 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 required for the examples
brew install pkg-config autoconf automake zip imagemagick sox

Once ngdevkit packages are installed, you can clone the ngdevkit-examples repository and build all the examples with the following commands:

git clone --recursive https://github.com/dciabrin/ngdevkit-examples examples
autoreconf -iv
./configure
make

You can learn how to use the devkit and how to build your first Neo-Geo program by reading the dedicated examples/README.md.

Building the devkit from sources

The devkit itself is a collection of various git repositories. 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.

Pre-requisite

In order to build the devkit you need autoconf, autoconf-archive and GNU Make 4.x. The devkit tools uses Python 3 and PyGame. The emulator requires SDL 2.0 and optionally OpenGL libraries. The examples require ImageMagick for all the graphics trickery. Various additional dependencies are required to build the toolchain modules such as GCC and SDCC.

For example, on Debian Buster, you can install the dependencies with:

apt-get install autoconf autoconf-archive automake gcc curl zip unzip
apt-get install libsdl2-dev
apt-get install python3-pygame
GCC_VERSION_PKG=$(apt-cache depends gcc | awk '/Depends.*gcc/ {print $2}')
# make sure you have src packages enabled for dependency information
echo "deb-src http://deb.debian.org/debian buster main" > /etc/apt/sources.list.d/ngdevkit.list
apt-get update
# install build-dependency packages
apt-get build-dep $GCC_VERSION_PKG
apt-get build-dep --arch-only sdcc
# dependencies for the example ROMs
apt-get install imagemagick sox libsox-fmt-mp3
# optional: install GLEW for OpenGL+GLSL shaders in GnGeo
apt-get install libglew-dev

If running OS X, you will need XCode, brew and GNU Make 4.x. Please note that the version of GNU Make shipped with XCode is tool old, so you need to install it from brew and use gmake instead of make as explained later in this manual. Install the dependencies with:

brew install gmake
brew install autoconf-archive
brew install glew sdl2 sdl2_image
brew install python3
# make sure you use brew's python3 to install pygame
export PATH=/usr/local/opt/python3/bin:$PATH
pip3 install pygame
brew deps gcc | xargs brew install
brew deps sdcc | xargs brew install
# dependencies for the example ROMs
brew install zip imagemagick sox

Compiling the devkit for Windows 10 is supported via WSL, detailed setup and build instructions are available in the the dedicated README.

Building the toolchain

The devkit relies on autotools to check for dependencies and autodetect the proper build flags. You can build the entire devkit in your local git repository with:

autoreconf -iv
./configure --prefix=$PWD/local
make
make install

If compiling on OS X, please use gmake instead of make as the version of GNU Make shiped with XCode is too old (currently 3.x) and the devkit won't compile with it.

Building examples ROMs with the devkit

Bundled with the devkit is a series of examples that is automatically downloaded when you build ngdevkit.

In order to build the examples, you need to have the devkit binaries available in your path. This can be done automatically with:

eval $(make shellinit)

This configures your environment variables to have access to all the binaries from the toolchain, including the emulator and the debugger. Then, you can just jump into the examples directory and let the configure script autodetect everything for you:

cd examples
./configure
make

This will compile all the examples available in the directory.

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're 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 $(make -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:

eval $(make shellinit)
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:

eval $(make shellinit)
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

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/.