CARD

BIOSF_CRDACCESS ($C00468): Perform memory card operation

Warning: register contents aren't preserved !

(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)

Error handling

Errors may occur and the BIOS will store a value in BIOS_CRDRESULT depending on what went wrong:

Bit	7	6	5	4	3	2	1	0
Def	Error occured	0				Error code

Error codes:

• 0: no card inserted
• 1: card inserted, but not formatted
• 2: attempted to load a file that doesn't exist on the card
• 3: checksum error?
• 4: attempted to save to a full card
• 5: card write protect switch is active