Ghidra Sega Saturn Loader

A (WIP) Ghidra loader for the Sega Saturn. Currently supports:

• ISO disc images
• Mednafen Save States (MC)
• Yabause Save States (YSS)

Grab from Releases or build from source.

Screenshots

Loader screenshot

Disassembly View w/Decompiler

How to Use

Sega Saturn ISOs

• Select any Sega Saturn ISO file
• At the "Container file detected" prompt, select "Single file"
• The loader will create functions for main, initial program (the code that runs during the Sega logo), and security_check
• Pros: Easy to use, useful for debugging game initialization, works great on Saturn homewbrew
• Cons: Doesn't load any file after the first file on disc

Mednafen Save States (MC)

• gunzip the Mednafen save state
• Select the unzipped file in Ghidra
• The loader will load backup cart memory, high work RAM, and low work RAM to the correct places
• The loader will add labels for SH-2s PC, PR, and R15 registers

Yabause Save States (YSS)

• Select any Yabause Save State (YSS)
• The loader will load backup cart memory, high work RAM, and low work RAM to the correct places
• The loader will add labels for SH-2s PC, PR, and R15 registers

Applying Sega Saturn Library Signatures

• After loading in Ghidra, open "Script Manager" and execute ApplySig.py
• Select the signature file to apply

Issues

• Code quality needs serious improvement and refactoring
• Memory map doesn't handle mirrored regions
• Adding the onchip register region (0xffffffe00-0xffffffff) to the memory map made decompilation worse. So it's disabled.
• It would be useful to label some globals to assist reversing
• Mednafen memory cart data doesn't match Yabause's.

Building

• gradle -PGHIDRA_INSTALL_DIR=<Absolute path to Ghidra>
• The output zip file will be created within /dist

Installation

• Ghidra 9.1 added SH-1/SH-2 support.
• Copy the zip file to <Ghidra install directory>/Extensions/Ghidra.
• Start Ghidra and use the "Install Extensions" dialog to finish the installation. (File -> Install Extensions...).
• (Optional but recommended) Install the ApplySig script so you can use Sega Saturn library signatures. Copy to a ghidra_scripts directory.
• (Optional but recommended) Download CyberWarriorX's Sega Saturn library signatures

Credits/References

• Yabause - Sega Saturn emulator used to sanity check loader
• cyberwarriorx/yssloader - YSS loader for IDA Pro
• Sega Saturn SH-2 Memory Map
• ISO 9660 Documentation
• ApplySig - python script to load IDA Pro library signatures into Ghidra.
• Sega Saturn Library Signatures - CyberWarriorX's Sega Saturn library signatures
• Thank you to @mumbel, @loudinthecloud, and the Ghidra team for helping get the SuperH plugin merged to Ghidra
• Thank you to @TrekkiesUnite118 for Java help and code review advice
• Thank you to @CyberWarriorX for tons of amazing open source Saturn utilities