Files
libretro/platforms
Abdessamad Derraz 801af113b7 feat: record every core a rom folder offers
The rom folders files kept the default core of each folder only, so a
core the user picks in the frontend's menu was not known to read its
sets there. Each folder now lists its offers: every <core> of every
<emulator> in AmberELEC's es_systems.cfg (arcade:
packages/ui/emulationstation/config/es_systems.cfg:116-150), every core
of EmuELEC's es_systems.json, every add_emu_core of ROCKNIX's emulators
package.mk with the device case it is written under (arcade: 218-229),
and the emulator of every ES-DE <command>. A core written under every
branch of a case is offered unconditionally. The ES-XML, ES-JSON,
ELEC-conf and ES-DE setups are rescraped at their pins: archr, arkos,
chaos, darkos, jelos, kolos, pan4elec, retrobat and unofficialos gain
the same records and nothing else.

A libretro core offered for a folder reads the sets it loads beside the
game there, as the default one does.

Manifests, roms folders gaining sets read beside the game:
- AmberELEC: +215 (293.1 MB) in fbneo, arcade and mame, for MAME 2010,
  2015, 2016 and 2003-Plus. 1 omission leaves.
- EmuELEC: +291 (232.0 MB) in cps1, cps2, cps3, mame, fbneo and
  arcade, for MAME 2010 and 2003-Plus. 47 omissions leave.
- ROCKNIX: +501 (538.7 MB) in fbneo, neogeo, cps1, cps2, cps3, arcade
  and mame, for MAME 2010, 2015 and 2003-Plus. 120 omissions leave.
- EmuDeck: +306 (251.2 MB) in cps, cps1, cps2, cps3, arcade and mame,
  for MAME 2000, 2003, 2003-Plus and 2010. 92 omissions leave.
Each omission that leaves was a set named as read outside the BIOS
folder. RetroDECK and the other platforms do not change. No file
leaves, and verify --all keeps its severity and status counts.
2026-11-11 12:57:45 +01:00
..
2026-11-09 07:16:19 +01:00
2026-11-09 07:16:19 +01:00

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.yml inherits retroarch, retropie.yml inherits retroarch

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:

  1. Add entry to _data_dirs.yml with source URL, extraction path, cache location
  2. Reference via data_directories: [{ref: key, destination: path}] in platform systems
  3. For scraper-generated platforms, add to SYSTEM_DATA_DIRS in the scraper
  4. 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

  1. Create platforms/<name>.yml
  2. Set base_destination (system or bios), verification_mode, hash_type
  3. Use includes: [group] for systems with subdirectory requirements
  4. Use inherits: retroarch to share RetroArch's file set
  5. Add platform-specific overrides in overrides.systems
  6. Test: python scripts/verify.py --platform <name>

Adding a shared group

  1. Add the group to _shared.yml with a source ref comment
  2. Include: filename, destination with subdirectory prefix, required flag, hashes
  3. Reference via includes: [group_name] in platform system definitions
  4. For scraper-generated platforms, add the mapping in the scraper's SYSTEM_SHARED_GROUPS dict 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