Software DIPs
Software DIPs are a list of a maximum of 14 game-specific settings. They can be modified from the MVS System ROM menu, or with system ROM hacks for other systems.
The settings names and their possible values are stored in the game's 68k program header in a specific format, read by the system ROM to form a menu.
On the MVS, the settings are saved for each game in the backup RAM.
The settings are copied from backup RAM to user RAM to BIOS_GAME_DIP ($10FD84) just before the game is started up. If no settings are found, they're initialized to the default values.
(Does the system ROM check values pulled from the backup RAM against the bounds given by the game ? Can a corrupt backup RAM save make games crash with out of bounds settings ?)
Software DIPs settings aren't available on the AES, the system ROM always loads the game's default values.
Config data description
Most of the following information by ElBarto:
| 0x00 | 16 bytes | Game name, no termination char required. |
| 0x10 | 6 bytes | Special settings list, 4 entries. See description below. |
| 0x16 | 10 bytes | Simple settings list, up to 10 entries. See description below. |
| 0x20 | x*12 bytes | String table. Strings are 12 bytes long and padded with 0x20 (space). Max number ? |
Special settings list
The special settings list holds 4 entries: the first 2 are for time settings, and the last 2 are for count settings.
A time setting occupies one word, which defines the default value:
- The upper byte is the minutes (up to 29, in BCD).
- The lower byte is the seconds (in BCD).
An unused time setting must be set to 0xFFFF.
A count setting occupies one byte, which defines the default value (not in BCD). The first count setting can go from 1 to 99. The second count setting is a "number of times", it can go from 0 (displayed as "WITHOUT") to 100 (displayed as "INFINITE").
An unused count setting must be set to 0xFF.
All special settings use a single string from the strings table, for the setting's name.
Simple settings list
Each options occupies one byte.
The upper 4 bits define the default value (starts from 0) and the lower 4 bits the number of choices.
A few games have a simple setting entry in entry #7 with a number of choices set to zero, to show a "▼NEXT PAGE" string on the bottom of the MVS menu. This is not done automatically by the system ROM.
Examples
dc.b "TEST ROM " ; Game name
dc.w $FFFF ; Special settings list (none used)
dc.w $FFFF
dc.b $FF,$FF
dc.b $24 ; Simple setting 1: 4 choices, default is #2
dc.b $02 ; Simple setting 2: 2 choices, default is #0
dc.b $00,$00,$00,$00,$00,$00,$00,$00
; String table:
dc.b "LIVES " ; Simple setting 1's description
dc.b "1 " ; Simple setting 1's choices
dc.b "2 "
dc.b "3 "
dc.b "4 "
dc.b "HOW TO PLAY " ; Simple setting 2's description
dc.b "WITH " ; Simple setting 2's choices
dc.b "WITHOUT "
|
|
dc.b "TEST ROM " ; Game name
dc.w $4220 ; Special setting 1: 42 minutes 20 seconds
dc.w $2042 ; Special setting 2: 20 minutes 42 seconds
dc.b $42 ; Special setting 3: 66
dc.b $64 ; Special setting 4: 100 ("INFINITE")
dc.b $24 ; Simple setting 1: 4 choices, default is #2
dc.b $02 ; Simple setting 2: 2 choices, default is #0
dc.b $00,$00,$00,$00,$00,$00,$00,$00
dc.b "TIMER 1 " ; Special setting 1's description
dc.b "TIMER 2 " ; Special setting 2's description
dc.b "COUNTER " ; Special setting 3's description
dc.b "COUNTER SPE " ; Special setting 4's description
dc.b "LIVES " ; Simple setting 1's description
dc.b "1 " ; Simple setting 1's choices
dc.b "2 "
dc.b "3 "
dc.b "4 "
dc.b "HOW TO PLAY " ; Simple setting 2's description
dc.b "WITH " ; Simple setting 2's choices
dc.b "WITHOUT "
