System ROM
The system ROM (often called BIOS) is a ROM containing code for the 68k startup program, some lookup tables, and various generic functions which can or must be used by games. They are present in all hardware types in various versions. The NeoGeo CD system ROM also contains graphics, sound, and Z80 code.
Official system ROMs have their nationality set by the byte at address $000401 (0=Japan, 1=US, 2=Euro), and their type set by the byte at $000400 (0=AES, $80=MVS).
Hashes
Copied from MAME's source code.
| Ref. | Version | CRC32 | SHA-1 |
| SP-S | Europe MVS (V1) | C7F2FA45 | 09576FF20B4D6B365E78E6A5698EA450262697CD |
| SP-S2 | Europe MVS (V2) | 9036D879 | 4F5ED7105B7128794654CE82B51723E16E389543 |
| SP-E | US MVS (V1) | 2723A5B5 | 5DBFF7531CF04886CDE3EF022FB5CA687573DCB8 |
| SP-U2 | US MVS (V2?) | E72943DE | 5C6BBA07D2EC8AC95776AA3511109F5E1E2E92EB |
| V2 | US MVS (4-slot V2) | 62F021F4 | 62D372269E1B3161C64AE21123655A0A22FFD1BB |
| ASIA-S3 | Asia MVS (V3) | 91B64BE3 | 720A3E20D26818632AEDF2C2FD16C54F213543E1 |
| VS-BIOS | Japan MVS (V3) | F0E8F27D | ECF01EDA815909F1FACEC62ABF3594EAA8D11075 |
| SP-J2 | Japan MVS (V2) | ACEDE59C | B6F97ACD282FD7E94D9426078A90F059B5E9DD91 |
| SP1 | Japan MVS (V1) | 9FB0ABE4 | 18A987CE2229DF79A8CF6A84F968F0E42CE4E59D |
| SP-45 | Asia MVS (V4.5) | 03CC9F6A | CDF1F49E3FF2BAC528C21ED28449CF35B7957DC1 |
| JAPAN-J3 | Japan MVS (V3) | DFF6D41F | E92910E20092577A4523A6B39D578A71D4DE7085 |
| SP-1V1 | Hotel unit (V1.3) | 162F0EBE | FE1C6DD3DFCF97D960065B1BB46C1E11CB7BF271 |
| NEO-EPO | Export AES | D27A71F1 | 1B3B22092F30C4D1B2C15F04D1670EB1E9FBEA07 |
| NEO-PO | Japan AES | 16D0C132 | 4E4A440CAE46F3889D20234AEBD7F8D5F522E22C |
| DEBUG | Dev. Sys. | 698EBB7D | 081C49AA8CC7DAD5939833DC1B18338321EA0A07 |
Use
The system ROM contents are simply mapped at $C00000 and available at all times.
See:
Home system
Size: 128KiB. Named NEO-EP0.
MVS
Size: 128KiB. Often named "SP" for System Program. Many different versions.
-
SP-S2 in PROM/MaskROM
-
SP1 in EPROM
-
SPJ Japanese system ROM on a ROM-only arcade board.
CD/CDZ
Size: 512KiB.
- FRONT-SP1 (Front loader)
- TOP-SP1 (Top loader using LC8953)
- TOP-SP2 (Top loader using LC98000)
- TOP-SPD (CDZ)
Contains Z80 and 68k programs, ADPCM sound, and graphics which are copied to the corresponding DRAMs at boot time. There is no SFIX ROM or SM1 ROMs in CD systems (but still a LO ROM).
The CD1 and CD2 system ROMs contain credits organized to be displayed on the fix layer (how can this be seen ?):
- Noriyuki Higashi is the infamous "Mr.Noric".
- Toshiya Yahara is cited as the inventor of the NeoGeo Pocket power supply in an SNK patent.
- Jo(h)n Guso is credited as a programmer in several games.
Sound drivers
The CD1 and CD2 system ROMs (FRONT-SP1 and TOP-SP1/SP2) include the "Ver 3.0 by Mr.Noric.1993/11/10 14:00" Z80 sound driver.
The CDZ version includes the "Ver 3.0 by MAKOTO.04/03/10 to SK" driver.
UniBIOS
Hacked MVS system ROM with various added functionalities such as cheats, debug DIPs settings, region and system switch, CRC checking, a jukebox, error handling. See Universe BIOS.
Neopen BIOS
Opensource AES/MVS system ROM in development. See Neopen BIOS.