Game & Watch - RetroBIOS¶
| Type | libretro |
| Source | https://github.com/libretro/gw-libretro |
| Version | Git |
| Profiled | 2026-03-18 |
| Cores | gw |
| Systems | handheld-electronic |
No BIOS or firmware files required. This core is self-contained.
gw-libretro runs Game & Watch simulators converted from MADrigal's Pascal source code via pas2lua. Each game is a self-contained .mgw archive (bzip2 compressed tar v7) containing Lua scripts, sprites, and sound data.
retro_get_system_info (libretro.c:187-194) sets valid_extensions to "mgw", need_fullpath to false, and block_extract to false. The core reads content entirely from the retro_game_info buffer passed by the frontend.
retro_load_game (libretro.c:256-310) passes the content buffer to gwrom_init() which decompresses and parses the tar archive in memory. gwlua_create() then initializes the Lua VM from the archive entries.
The core never calls RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY, never opens files from the filesystem, and has no firmware or BIOS dependencies. All game data is bundled in the .mgw content files available from libretro's buildbot (bot.libretro.com/assets/cores/HandheldElectronicGame/).
No external BIOS or firmware files are needed.
Generated on 2026-03-20T19:12:20Z