BIOS RAM locations

Address	DEF name	Size	Set by	Description
$10FCEE	?	byte	GAME	Z80/M ROM check pass
$10FCEF	BIOS_SLOTCHECK	byte	BIOS	Slot check passed if non-zero
$10FD80	BIOS_SYSTEM_MODE	byte	BIOS	0:BIOS wants vblank (system mode), $80:ok to use vblank (game mode)
$10FD82	BIOS_MVS_FLAG	byte	BIOS	0:AES, 1:MVS
$10FD83	BIOS_COUNTRY_CODE	byte	BIOS	0:Japan, 1:USA, 2:Europe
$10FD84~$10FD93	BIOS_GAME_DIP	16 bytes	BIOS	Software DIPs values
$10FD94	BIOS_P1STATUS	byte	BIOS	0:No connection, 1:Normal joypad, 2:Expanded joypad, 3:Mahjong controller, 4:Keyboard
$10FD95	BIOS_P1PREVIOUS	byte	BIOS	Previous frame DCBA Right Left Bottom Top (positive logic)
$10FD96	BIOS_P1CURRENT	byte	BIOS	Current frame DCBA Right Left Bottom Top (positive logic)
$10FD97	BIOS_P1CHANGE	byte	BIOS	Active edge DCBA Right Left Bottom Top (positive logic)
$10FD98	BIOS_P1REPEAT	byte	BIOS	Active edge + repeat every 8 frames after 16 frames. DCBA Right Left Bottom Top (positive logic)
$10FD99	BIOS_P1TIMER	byte	BIOS	Countdown ?
$10FD9A~$10FD9F	Same for P2	5 bytes	BIOS	See above
$10FDA0~$10FDA6	Same for P3	5 bytes	BIOS	See above
$10FDA7~$10FDAB	Same for P4	5 bytes	BIOS	See above
$10FDAC	BIOS_STATCURNT	byte	BIOS	Select P4, Start P4, Select P3, Start P3, Select P2, Start P2, Select P1, Start P1 (positive logic)
$10FDAD	BIOS_STATCHANGE	byte	BIOS	Select P4, Start P4, Select P3, Start P3, Select P2, Start P2, Select P1, Start P1 (positive logic)
$10FDAE	BIOS_USER_REQUEST	byte	BIOS	Request for the USER subroutine. 0:Init, 1:Boot animation, 2:Demo, 3:Title
$10FDAF	BIOS_USER_MODE	byte	Game	Used by the game to tell what it's doing: 0:Init/Boot animation, 1:Title/Demo, 2:Game Game selection can only be done on MVS systems when this byte is < 2
$10FDB0	BIOS_CREDIT_DEC	4 bytes	Game	Credit decrement value for each player when calling CREDIT DOWN.
$10FDB4	BIOS_START_FLAG	byte	BIOS	Used when calling the PLAYER START subroutine. Last 4 bits correspond to the player who pushed start.
$10FDB6	BIOS_PLAYER_MOD	4 bytes	Game	Sets player status. 0:Never played, 1:Playing, 2:Continue option being displayed, 3:Game over
$10FDBE	BIOS_MESS_POINT	longword	Game	MESS_OUT buffer pointer
$10FDC2	BIOS_MESS_BUSY	byte	Game	0:Allow MESS_OUT, 1:Skip MESS_OUT
$10FDC6	MEMCARD_PRESENT	byte	BIOS	$80 : Not present, $81 : Present
$10FE88		longword	BIOS	Frame counter, updated by SYSTEM_IO
$10FEE4		byte	BIOS	Frame counter (internal)

; Memory card related:
*BIOS_CRDF       equ $10FDC4 ;byte: function to perform when calling BIOSF_CRDACCESS, see below table
*BIOS_CRDRESULT  equ $10FDC6 ;byte: 00 on success, else 80+ and encodes the error, see below table
*BIOS_CRDPTR     equ $10FDC8 ;longword: pointer to read from/write to
*BIOS_CRDSIZE    equ $10FDCC ;word: how much data to read/write from/to card
*BIOS_CRDNGH     equ $10FDCE ;word: usually game NGH. Unique identifier for the game that 'owns' the save file
*BIOS_CRDFILE    equ $10FDD0 ;word: each NGH has up to 16 save 'files' associated with

; Calendar, only on MVS (in BCD)
*BIOS_YEAR       equ $10FDD2 ;last 2 digits of year
*BIOS_MONTH      equ $10FDD3
*BIOS_DAY        equ $10FDD4
*BIOS_WEEKDAY    equ $10FDD5 ;Sunday = 00, Monday = 01 ... Saturday = 06
*BIOS_HOUR       equ $10FDD6 ;24 hour time
*BIOS_MINUTE     equ $10FDD7
*BIOS_SECOND     equ $10FDD8

*BIOS_SELECT_TIMER equ $10FDDA ;Byte: game start countdown
*BIOS_DEVMODE      equ $10FE80 ;Byte: non-zero for developer mode

; Upload to DRAM
*BIOS_UPDEST     equ $10FEF4 ;longword: destination address (!)
*BIOS_UPSRC      equ $10FEF8 ;longword: source address
*BIOS_UPSIZE     equ $10FEFC ;longword: size
*BIOS_UPZONE     equ $10FEDA ;byte: zone (0=PRG, 1=FIX, 2=SPR, 3=Z80, 4=PCM, 5=PAT)
*BIOS_UPBANK     equ $10FEDB ;byte: bank