Abdessamad Derraz
602945faf0
- The installer says "Every file on the list is in place." where it said "Everything is in place.": a check covers the files the collection holds, and the required ones it lacks follow. - The FAQ, first install, legal and home pages state only what the code shows (PlayStation 1 and Saturn run without a BIOS on some emulators, save files are never touched, records are added). - MinUI and MyMinUI show their own boot logos, and the Android, Linux handheld and iPhone tiles show the Android robot, Tux and a plain device icon, each credited in sources.json. - Each Markdown copy, llms.txt and llms-full.txt name the commit they were built from, version.json the current one, and the answering rules tell assistants to fetch a stale copy again. - The deploy lists the pages whose words changed (digests.json) and posts them to IndexNow once the site is live.
Platform Configs
How platform YAML files work and where subdirectory requirements come from.
Files
_registry.yml-- platform metadata (name, release pack, display order)_shared.yml-- shared file groups with canonical destinations<platform>.yml-- per-platform BIOS declarations- Inheritance:
lakka.ymlinheritsretroarch,retropie.ymlinheritsretroarch
Shared groups (_shared.yml)
The subdirectory a BIOS goes into is determined by the libretro core, not
the platform. NP2kai expects np2kai/BIOS.ROM whether you're on RetroArch,
Batocera, or Recalbox. Only base_destination varies (system/ vs bios/).
Shared groups define files with correct destinations once. Platforms
reference them via includes: [group_name] in their system definitions.
load_platform_config() in common.py resolves includes at load time,
deduplicating by filename.
When to use shared groups: whenever 2+ platforms share files that a core expects in a specific subdirectory. The group carries the correct destination so platforms can't drift.
For RetroArch specifically, libretro_scraper.py injects includes:
references and applies subdirectory prefixes via CORE_SUBDIR_MAP during
generation. Manual edits to retroarch.yml will be overwritten on next scrape.
Data directories (_data_dirs.yml)
Some cores need entire directory trees, not just individual BIOS files.
Dolphin needs dolphin-emu/Sys/ (GameSettings, DSP firmware, fonts),
PPSSPP needs PPSSPP/ (font assets, shaders), blueMSX needs Databases/
and Machines/ (machine configs).
These are defined in _data_dirs.yml as a central registry with upstream
source URLs. The pack generator auto-refreshes from upstream before building
(use --offline to skip). Data directories live in data/ (not bios/)
and are NOT indexed in database.json.
Adding a data directory:
- Add entry to
_data_dirs.ymlwith source URL, extraction path, cache location - Reference via
data_directories: [{ref: key, destination: path}]in platform systems - For scraper-generated platforms, add to
SYSTEM_DATA_DIRSin the scraper - Run
python scripts/refresh_data_dirs.py --key <name>to populate the cache
Subdirectory reference
Each entry documents where the requirement comes from. Check these source files to verify or update the paths.
| Core | Subdirectory | Source |
|---|---|---|
| NP2kai | np2kai/ |
libretro-np2kai/sdl/libretro.c |
| PX68k | keropi/ |
px68k/libretro/libretro.c |
| QUASI88 | quasi88/ |
quasi88/src/libretro.c |
| Kronos | kronos/ |
libretro-kronos/libretro/libretro.c |
| ep128emu | ep128emu/rom/ |
ep128emu-core/src/libretro.cpp |
| Flycast | dc/ |
flycast/shell/libretro/libretro.cpp |
| FBNeo NeoCD | neocd/ |
fbneo/src/burn/drv/neogeo/neo_run.cpp |
| Fuse | fuse/ |
fuse-libretro/fuse/settings.c |
| hatari | hatari/tos/ |
hatari/src/tos.c |
Full libretro docs: https://docs.libretro.com/library/<core>/
Adding a platform
- Create
platforms/<name>.yml - Set
base_destination(systemorbios),verification_mode,hash_type - Use
includes: [group]for systems with subdirectory requirements - Use
inherits: retroarchto share RetroArch's file set - Add platform-specific overrides in
overrides.systems - Test:
python scripts/verify.py --platform <name>
Adding a shared group
- Add the group to
_shared.ymlwith a source ref comment - Include: filename, destination with subdirectory prefix, required flag, hashes
- Reference via
includes: [group_name]in platform system definitions - For scraper-generated platforms, add the mapping in the scraper's
SYSTEM_SHARED_GROUPSdict so it persists across regeneration
Verification modes
| Platform | Mode | Native logic | Upstream source |
|---|---|---|---|
| RetroArch | existence | path_is_valid() -- file exists |
core_info.c |
| Lakka | existence | inherits RetroArch | idem |
| RetroPie | existence | inherits RetroArch | idem |
| Batocera | md5 | md5sum() + checkInsideZip() |
batocera-systems |
| RetroBat | md5 | MD5 check via JSON config | batocera-systems.json |
| EmuDeck | md5 | MD5 whitelist per system | checkBIOS.sh |
| Recalbox | md5 | multi-hash comma-separated | es_bios.xml + Bios.cpp |
| RetroDECK | md5 | MD5 per file via component manifests | api_data_processing.sh |
| RomM | md5 | size + any hash (MD5/SHA1/CRC32) | firmware.py |
| ROCKNIX | md5 | md5sum() + checkInsideZip() with altmd5 |
rocknix-systems |
| MiSTer FPGA | md5 | MD5 of the file at its destination | process_db_index_worker.py |
| BizHawk | sha1 | SHA1 per firmware entry | FirmwareDatabase.cs |