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).
Copied from [MAME's source].
|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|
The system ROM contents are simply mapped at $C00000 and available at all times.
Size: 128KiB. Named NEO-EP0.
Size: 128KiB. Often named "SP" for System Program. Many different versions.
SPJ Japanese system ROM on a ROM-only arcade board.
- FRONT-SP1 (Front loader)
- TOP-SP1 (Top loader using LC8953)
- TOP-SP2 (Top loader using LC98000)
- TOP-SPD (CDZ)
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.
The CDZ version includes the "Ver 3.0 by MAKOTO.04/03/10 to SK" driver.
Opensource AES/MVS system ROM in development. See Neopen BIOS.