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RetroBIOS

Geargrafx

Geargrafx emulates NEC PC Engine, NEC SuperGrafx, NEC PC Engine CD and Pioneer LaserActive. It reads 7 files, 3 of them required: without a required file it does not start games. A required file is needed only by the machines that use it. Each file below cites the line of source code that reads it.

About this profile
Detail Value
Type libretro
Classification Official port
Source https://github.com/drhelius/Geargrafx
Version 1.8.5-10-g7c447b0, 10 commits after tag 1.8.5
Revision drhelius/Geargrafx@7c447b0bd46b
Profiled 2026-10-04
Profile YAML, JSON
Cores geargrafx
Systems NEC PC Engine, NEC SuperGrafx, NEC PC Engine CD, Pioneer LaserActive
Install this emulator's files

The installer finds your setup and its BIOS folder, then downloads only the files this emulator reads there and checks each one.

Open the Start menu. Type PowerShell and open it. Paste the line. Press Enter.

PowerShell
&([scriptblock]::Create((irm https://abdess.github.io/retrobios/i.ps1))) --emulator geargrafx
Technical notes

Geargrafx is a PC Engine / TurboGrafx-16 / SuperGrafx / CD-ROM emulator by Ignacio Sanchez (drhelius). HuCard games run without any external file.

CD-ROM content (cue, chd, mmi) needs a System Card image from the frontend system directory. load_bios() in platforms/libretro/libretro.cpp:761-802 picks the file name from the core option geargrafx_cdrom_bios (platforms/libretro/libretro.cpp:1645-1668): System Card 1 loads syscard1.pce, System Card 2 loads syscard2.pce, System Card 3 (the default) and Force Game Express load syscard3.pce. The older values Auto and Game Express are still accepted and map to the same. The path is "{system_directory}/{name}" (platforms/libretro/libretro.cpp:788). When the card is missing the core posts "CD-ROM BIOS not found" and continues (platforms/libretro/libretro.cpp:789-798). gexpress.pce is then always attempted from the same directory (platforms/libretro/libretro.cpp:800-801). load_bios() runs from retro_load_game() for CD content only (platforms/libretro/libretro.cpp:525-526) and again on retro_reset() when a CD is loaded (platforms/libretro/libretro.cpp:362-363). With the libretro VFS the file goes through load_bios_file() into LoadBiosFromBuffer(), otherwise through Media::LoadBios() (platforms/libretro/libretro.cpp:724-759, src/media.cpp:526-569).

Media::LoadBiosData() (src/media.cpp:740-783) strips a 512-byte header when the size is the expected size plus 512, then rejects any image whose size is not GG_BIOS_SYSCARD_SIZE (0x40000) or GG_BIOS_GAME_EXPRESS_SIZE (0x8000) (src/defines.h:53-54). CRC32 is computed over the accepted image. GatherBIOSInfoFromDB() (src/media.cpp:1121-1155) looks the CRC up in k_game_database entries flagged GG_GAMEDB_BIOS_SYSCARD or GG_GAMEDB_BIOS_GAME_EXPRESS (src/game_db.h:48-56). An unknown CRC marks the image "Unknown" and invalid but it is still used.

For CD content the ROM banks map onto the System Card buffer, or onto the Game Express buffer when the disc is a Game Express title (src/media.cpp:1188-1197). A Game Express disc is detected by its CRC in game_db.h (GG_GAMEDB_GAME_EXPRESS, src/media.cpp:1087-1091), named by the card field of an MMI image (src/media.cpp:915-917) or forced by the option (src/media.cpp:929-933). With no card loaded the buffer is zeros and the CD does not boot. Arcade Card titles are also detected from game_db.h and run on the selected System Card.

MMI content is a LaserActive LD-ROM2 image. retro_load_game() also calls load_pac_bios() for it (platforms/libretro/libretro.cpp:528-529), which reads the NEC PAC firmware from the system directory according to the core option geargrafx_laseractive_region (platforms/libretro/libretro.cpp:1680-1691): Japan loads pac-n1.bin and falls back to pce-lp1.bin, US loads pac-n10.bin, Auto (the default) loads both regions (platforms/libretro/libretro.cpp:827-849). Media::LoadPacBiosData() (src/media.cpp:648-710) accepts 0x80000 bytes (GG_BIOS_LASERACTIVE_SIZE, src/defines.h:55), with or without a 512-byte header, and compares the CRC32 with the values hardcoded for the region. An unknown CRC is logged and the image is still used. SelectPacBios() (src/media.cpp:712-738) follows the option, then the regionCode of the MMI image, then whichever region is loaded. An MMI image that names no card maps the PAC firmware (src/media.cpp:1188-1197), and one that names a card uses the System Card or Game Express buffer. retro_load_game() fails when the firmware the MMI image needs is not loaded (platforms/libretro/libretro.cpp:551-566).

Backup RAM is exposed through RETRO_MEMORY_SAVE_RAM (platforms/libretro/libretro.cpp:650-658) and saved by the frontend. A connected Memory Base 128 is persisted by the core itself as geargrafx_mb128.sav in the frontend save directory (platforms/libretro/libretro.cpp:851-931). Both are state the core writes, not files a user obtains.

Files

Section titled “Files”

7 files: 3 required, 4 optional.

In this collection: 7 in repo and 0 missing.

Required

Section titled “Required”
FileStatusHash

syscard3.pce

Super CD-ROM System Card 3.0

  • System: NEC PC Engine CD
  • Loaded for the default option value System Card 3 and for Force Game Express. game_db.h accepts three images under this name: Japan (CRC32 6D9A73EF), the Japan NuFont Hack (CRC32 0ECEA1F3, syscard3.pce patched with xlateFont-JPN.ips from dshadoff/SYSCARD_Translatefont) and USA (CRC32 2B5B75FE).
Hashes, validation and source
required for NEC PC Engine CD in repoCRC32 6d9a73ef

pac-n1.bin

LaserActive NEC PAC-N1 v1.02 (Japan)

  • System: Pioneer LaserActive
  • Japanese PAC firmware, read for MMI content when geargrafx_laseractive_region is Auto or Japan. The Japanese slot accepts the PAC-N1 and PCE-LP1 images under either file name.
Hashes, validation and source
required for Pioneer LaserActive in repo Region: JapanCRC32 a8cb694c

pac-n10.bin

LaserActive NEC PAC-N10 v1.02 (US)

  • System: Pioneer LaserActive
  • US PAC firmware, read for MMI content when geargrafx_laseractive_region is Auto or US.
Hashes, validation and source
required for Pioneer LaserActive in repo Region: North AmericaCRC32 01223dd5

Optional

Section titled “Optional”
FileStatusHash

syscard2.pce

CD-ROM System Card 2.0 / 2.1

  • System: NEC PC Engine CD
  • Loaded when geargrafx_cdrom_bios is System Card 2. game_db.h accepts v2.0 Japan (CRC32 52520BC6), v2.1 Japan (CRC32 283B74E0) and USA (CRC32 FF2A5EC3).
Hashes, validation and source
in repoCRC32 52520bc6

syscard1.pce

CD-ROM System Card 1.0 (Japan)

Hashes, validation and source
in repoCRC32 3f9f95a4

gexpress.pce

Games Express CD Card

  • System: NEC PC Engine CD
  • Always attempted after the System Card, used for discs flagged GG_GAMEDB_GAME_EXPRESS in game_db.h, for MMI images whose card is Games Express, or when the option is Force Game Express. game_db.h accepts the Blue Version (CRC32 51A12D90) and the Green Version (CRC32 16AAF05A). Both CRCs are of 32768-byte images: the 16384-byte Green dump (CRC32 20E0A364) is rejected on size and matches 16AAF05A once zero-padded to 32768 bytes.
Hashes, validation and source
in repoCRC32 51a12d90

pce-lp1.bin

LaserActive NEC PCE-LP1 v1.02 (Japan)

Hashes, validation and source
in repo Region: JapanCRC32 76116a02

Profile data

Section titled “Profile data”
Valid BIOS CRC32

  • syscard:

    • crc32: 3F9F95A4, name: CD-ROM System Card 1.0 (J)
    • crc32: 52520BC6, name: CD-ROM System Card 2.0 (J)
    • crc32: 283B74E0, name: CD-ROM System Card 2.1 (J)
    • crc32: 6D9A73EF, name: Super CD-ROM System 3.0 (J)
    • crc32: 0ECEA1F3, name: Super CD-ROM System 3.0 (J) NuFont Hack
    • crc32: FF2A5EC3, name: TurboGrafx CD System Card 2.0 (USA)
    • crc32: 2B5B75FE, name: TurboGrafx CD Super System 3.0 (USA)

  • game express:

    • crc32: 51A12D90, name: Games Express CD Card Blue Version (J)
    • crc32: 16AAF05A, name: Games Express CD Card Green Version (J)

  • laseractive japan:

    • crc32: A8CB694C, name: PAC-N1 v1.02
    • crc32: 76116A02, name: PCE-LP1 v1.02

  • laseractive us:

    • crc32: 01223DD5, name: PAC-N10 v1.02

Next steps

Section titled “Next steps”
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Maintained by Abdess on GitHub. Report a problem.

Packs from release v2026.10.10, .

MIT for the tooling and metadata. BIOS and firmware files are third-party system software, preserved for personal backup, archival and interoperability.