Mega Man X4

A matching decompilation of Mega Man X4 (PlayStation, 1997).

The same C source builds:

• byte-matching PlayStation executables for the US, JP and EU releases
• a native PC port for Linux (US and JP)
• a non-matching Sega Saturn build

This repository does not contain any game assets. You need your own copy of the game.

Versions

Version	Executable	Compiler	Checksums
US	SLUS_005.61	GCC 2.7.2	check.us.txt
JP	SLPS_009.02	GCC 2.7.2	check.jp.txt
EU	SLES_011.76	GCC 2.8.1	check.eu.txt
Saturn US	0.BIN, X4LOW.X4	sh-elf-gcc (retail: SHC)	non-matching

Building the PlayStation executables

Install the dependencies:

sudo apt-get update
sudo apt-get install binutils-mipsel-linux-gnu gcc-mipsel-linux-gnu ninja-build

pip install -r requirements.txt

git submodule update --init --recursive
sh compiler.sh

Copy the executable from your disc into disks/<version>/, for example disks/us/SLUS_005.61. Then split and build:

splat split config/SLUS_005.61.splat.yaml
sh build.sh

For the other versions, split with config/SLPS_009.02.splat.yaml or config/SLES_011.76.splat.yaml and run VERSION=jp sh build.sh or VERSION=eu sh build.sh. build.sh checks the result against check.<version>.txt.

Building the PC port

sudo apt-get install build-essential cmake ninja-build \
    libx11-dev libxext-dev libxrandr-dev libxcursor-dev \
    libxfixes-dev libxi-dev libxss-dev libxtst-dev

cmake -S . -B build-linux -G Ninja -DCMAKE_BUILD_TYPE=Release -DMMX4_PC_VERSION=us
cmake --build build-linux --parallel

Use -DMMX4_PC_VERSION=jp for the Japanese version. The port reads the game data from a disc image, disks/mmx4.us.cue (or disks/mmx4.jp.cue) by default. Pass --cue or set MMX4_CUE to use another path:

build-linux/mmx4_pc --cue path/to/game.cue

Building for Saturn

The Saturn build uses GCC (sh-elf-gcc) instead of Hitachi's SHC compiler. We don't have the exact SHC version the original was built with, so it doesn't match byte for byte.

sudo apt-get install gcc-sh-elf binutils-sh-elf ninja-build
git submodule update --init tools/saturn/sdk
python3 tools/saturn/saturn_native_build.py --output build/saturn-native --jobs $(nproc) --no-disc

Contributing

See the Getting Started page on the wiki.

Project layout

Path	Contents
src/main	decompiled game code
src/pc	PC port platform layer
src/saturn	Saturn platform layer
include	shared headers
config	splat configs, symbol lists
tests	unit tests
tools	build, matching and testing tools