BIOS calls

Please see ASM Defines or C Defines for the hex addresses.

Simplify hierarchy and tell on which system each call works ?

= Generic BIOS calls =

BIOS calls common to every system.

BIOSF_VBL ($C0044A): Multiple purpose VBL routine
Sets values in RAM according to buttons states, checks CDDA commands, probably other things... Always (?) called each frame by games.

Memory locations set (all 8bit): BIOS_P1CURRENT    $10FD95 Joystick 1 state BIOS_P1PREVIOUS   $10FD96 Previous joystick 1 state BIOS_P1CHANGE     $10FD97 Joystick 1 state change (edges) BIOS_P1REPEAT     $10FD98 Joystick 1 repeat (edge, and strobe if held more than ? calls)

BIOS_P2CURRENT    $10FD9B Joystick 2 state BIOS_P2PREVIOUS   $10FD9C Previous joystick 2 state BIOS_P2CHANGE     $10FD9D Joystick 2 state change (edges) BIOS_P2REPEAT     $10FD9E Joystick 2 repeat (edge, and strobe if held more than ? calls)

BIOS_STATCURNT    Joystick 1/2 start/select state BIOS_STATCHANGE   Previous Joystick 1/2 start/select state

Bit definitions: see Joypad

= AES/MVS BIOS calls =

SP-E jump table:

BIOSF_CRDACCESS ($C00468): Perform memory card operation
(Informations provided by User:Smkdan)

Memory locations used:

BIOS_CRDF      (8bit): function to perform when calling BIOSF_CRDACCESS, see below table BIOS_CRDRESULT (8bit): 00 on success, else 80+ and encodes the error, see below table BIOS_CRDPTR    (32bit): pointer to read from/write to BIOS_CRDSIZE    (16bit): how much data to read/write from/to card BIOS_CRDNGH    (16bit): usually game NGH. Unique identifier for the game that 'owns' the save file BIOS_CRDFILE   (16bit): each NGH has up to 16 save 'files' associated with

To access memory card, the RAM addresses above must be set depending on the function being attempted BIOS_CRDF values:


 * $00 (Format)
 * No extra parameters


 * $01 (Find)
 * In: BIOS_CRDNGH: NGH to find save files for
 * Out: BIOS_CRDFILE: 16bit mask containing 1 bits for each one of the 16 save files if present.
 * 0 bits mean the save file is not present. i.e. FFFF = all 16 saves used, 8000 = only save file 15 is used


 * $02 (Load)
 * In:
 * CRDPTR: pointer to store loaded data to
 * CRDSIZE: the max size of data to load (automatically stops when entire file is loaded)
 * CRDNGH: NGH of file
 * CRDFILE: the file # of the given NGH to load from


 * $03 (Save)
 * In:
 * CRDPTR: pointer to read data to store to the card
 * CRDSIZE: size of data to save
 * CRDNGH: NGH of file
 * CRDFILE: the file # of the given NGH to save as


 * $04 (Delete)
 * In:
 * CRDNGH: NGH of file
 * CRDFILE: the file # of the given NGH to delete


 * $05 (GETNAME)
 * Gets name of a save file, forgot how these work...


 * $06 (SETUSER) (the username of the card)
 * $07 (GETUSER)

Errors may occur and the BIOS will store a value in BIOS_CRDRESULT depending on what went wrong:
 * $00: no errors
 * $80: no card inserted
 * $81: card inserted, but not formatted
 * $82: attempted to load a file that doesn't exist on the card
 * $83: checksum error?
 * $84: attempted to save to a full card
 * $85: card write protect switch is active

= CD BIOS calls =

Same ones as the AES/MVS ?

BIOSF_UPLOAD ($C00546): Upload data to DRAM
BIOS_UPSRC     (32bit): Source (Long) BIOS_UPDEST    (32bit): Destination (Long) BIOS_UPSIZE    (32bit): Size (Long) BIOS_UPZONE    (8bit):  Zone (Byte, 0=PRG, 1=FIX, 2=SPR, 3=Z80, 4=PCM, 5=PAT) BIOS_UPBANK    (8bit):  Bank (Byte)

For FIX, Z80 (, PAT ?) and PCM upload, the destination has to be multiplied by 2 (8bit busses). The SPR bank size is 1MiB (4 banks), PCM bank size is 512KiB (4 banks). The other zones aren't banked.

BIOS_UPDEST (and BIOS_UPSRC ?) is incremented by the size upon completion, which allows to do multiple consecutive uploads.

BIOSF_LOADFILE ($C00552): Load file from CD (with animation)
A0 points to a file information block made of:
 * The file name, ends with 0 (32 chars buffer ?)
 * The destination bank (8bit)
 * Eventual padding bytes to align the destination
 * Destination (32bit)

Example (?): "STAGE_2.SPR",0x02,0x00,0x1600 loads STAGE_2.SPR at $201600 in the sprite DRAM.

For FIX, Z80 (, PAT ?) and PCM files, the destination is multiplied by 2 (8bit busses).

The destination memory is automatically chosen according to the file's extension.

BIOSF_CDDACMD ($C0056A): Issue CDDA command
Command/track pair in D0. Hooks the VBL interrupt for a while.

= CDZ BIOS calls =

Check track 0 ? Copy protection