NeoCD - RetroBIOS

Type	libretro
Classification	Pure libretro
Source	https://github.com/libretro/neocd_libretro
Version	2022
Profiled	2026-03-24
Cores	neocd
Systems	snk-neogeo-cd

Technical notes

Complete rewrite of NeoCD in C++11. Scans {system_dir}/neocd/ for any .rom or .bin file, also inside .zip archives (src/libretro_bios.cpp:69-105, src/path.cpp:6 NEOCD_SYSTEM_SUBDIR = "neocd").

BIOS identified by binary pattern matching at fixed ROM addresses, not by filename (src/bios.cpp:167-206). Files are auto byte-swapped if needed (src/bios.cpp:148-160). Files smaller than 524288 bytes are skipped (src/libretro_bios.cpp:42).

Three hardware families detected: Front Loader, Top Loader, CDZ. Modified variants recognized: SMKDan 0.07, SMKDan 0.07b, Universe BIOS 3.2, Universe BIOS 3.3 (src/bios.h:11-27). Any single valid BIOS is sufficient; selection via core options dropdown sorted alphabetically.

Y-ZOOM ROM (ng-lo.rom / 000-lo.lo) listed in .info but generated algorithmically, never loaded from file (src/memory.cpp:223-253 generateYZoomData, CRC32 E09E253C). These are phantom .info entries.

.info firmware_count=12 but 2 are phantoms (Y-ZOOM), effective count=10. .info lists uni-bioscd.rom as "Universe BIOS 3.2" but SHA1 matches Universe BIOS 3.3 (confirmed by GitHub README).

10 files | 0 required, 10 optional | 10 in repo, 0 missing

neocd_f.rom optional in repo

• Path: neocd/neocd_f.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:59 FRONT_LOADER_SEARCH_PATTERN at 0xC0006C
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Front Loader BIOS (big-endian, NeoCD naming)

front-sp1.bin optional in repo

• Path: neocd/front-sp1.bin
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:59 FRONT_LOADER_SEARCH_PATTERN, src/bios.cpp:148-160 autoByteSwap
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Front Loader BIOS (little-endian, MAME naming)

neocd_sf.rom optional in repo

• Path: neocd/neocd_sf.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:62 SMKDANBETA_FRONT_SEARCH_PATTERN at 0xC00004
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Front Loader BIOS, SMKDan 0.07b

neocd_t.rom optional in repo

• Path: neocd/neocd_t.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:60 TOP_LOADER_SEARCH_PATTERN at 0xC0006C
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Top Loader BIOS (big-endian, NeoCD naming)

top-sp1.bin optional in repo

• Path: neocd/top-sp1.bin
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:60 TOP_LOADER_SEARCH_PATTERN, src/bios.cpp:148-160 autoByteSwap
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Top Loader BIOS (little-endian, MAME naming)

neocd_st.rom optional in repo

• Path: neocd/neocd_st.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:63 SMKDANBETA_TOP_SEARCH_PATTERN at 0xC00004
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Top Loader BIOS, SMKDan 0.07b

neocd_z.rom optional in repo

• Path: neocd/neocd_z.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:61 CDZ_SEARCH_PATTERN at 0xC0006C
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• CDZ BIOS (big-endian, NeoCD naming)

neocd.bin optional in repo

• Path: neocd/neocd.bin
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:61 CDZ_SEARCH_PATTERN, src/bios.cpp:148-160 autoByteSwap
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• CDZ BIOS (little-endian, MAME naming)

neocd_sz.rom optional in repo

• Path: neocd/neocd_sz.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:64 SMKDANBETA_CDZ_SEARCH_PATTERN at 0xC00004
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• CDZ BIOS, SMKDan 0.07b

uni-bioscd.rom optional in repo

• Path: neocd/uni-bioscd.rom
• System: snk-neogeo-cd
• Size: 512.0 KB
• Source: src/bios.cpp:68 UNIVERSE33_SEARCH_PATTERN at 0xC00150
• Platforms: batocera, lakka, recalbox, retroarch, retrobat, retrodeck, retropie, romm
• Universe BIOS 3.3, CDZ-based third-party multi-region BIOS

Generated on 2026-04-18T08:05:07Z