PC FX BIOS

ROM Font

Address: 0xFFF0000C

r7 Value	Description
0	Kanji 16x16
1	Kanji 12x12
2	ANK 8x16
3	ANK 6x12
4	ANK 8x8
5	ANK 8x12

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Filesystem Functions

Calling Procedure

 Load r10 with function number.
 Add -8 to sp.
 Store lp to 0[sp]
 Store gp to 4[sp]

 Set gp to 0.
 Load r12 with 0xFFF00008
 JAL to local code that does JMP [r12]
 (Wait for return)
 Restore lp and gp from stack.
 Add 8 to sp.
 JMP [lp] (return)

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Definitions

/* DEV_CTRL & HND_CTRL NO */
#define CTRL_VEC_RD             0
#define CTRL_VEC_WT             1
#define CTRL_NAME_RD            2
#define CTRL_NAME_WT            3
#define CTRL_OPT_JOB            4
#define CTRL_IPLREAD            5
#define CTRL_IPLWRITE           6
#define CTRL_BPBGET             7
#define CTRL_BPBSET             8
#define CTRL_GETSTAT            9

/* open mode */
#define O_READ                  0x0001
#define O_WRITE                 0x0002
#define O_APPEND                0x0008  /* set append mode */
#define O_CREAT                 0x0200  /* create if nonexistant */
#define O_TRUNC                 0x0400  /* truncate to zero length */
#define O_EXCL                  0x0800  /* error if already exists */

/* error trap function */
#define IO_READ                 0
#define IO_WRITE                1
#define IO_CHECK                2
#define IO_CTRL                 3
#define IO_WCHECK               4

/* seek base */
#define SEEK_SET                0       /* TOF base */
#define SEEK_CUR                1       /* current base */
#define SEEK_END                2       /* EOF base */

/* attribute type */
#define ATR_ARC                 0x20
#define ATR_DIR                 0x10
#define ATR_VOL                 0x08
#define ATR_SYS                 0x04
#define ATR_HID                 0x02
#define ATR_RDO                 0x01

/* ipl block data offset */
#define bt_jmp                  0
#define bt_oem                  3
#define bt_secsiz               11
#define bt_clsiz                13
#define bt_nrsvsect             14
#define bt_nfat                 16
#define bt_dirents              17
#define bt_maxsect              19
#define bt_mid                  21
#define bt_fatlen               22
#define bt_nsect                24
#define bt_nheads               26
#define bt_nhs                  28
#define bt_bigsect              32
#define bt_junk                 36

/* error code */
#define BAD_PARA                -1
#define BAD_DRIVE               -10
#define PATH_OVER               -11
#define NAME_OVER               -12
#define EXT_OVER                -13
#define BAD_DEVICE              -14
#define NO_FILES                -15
#define BAD_PATH                -16
#define BAD_NAME                -17
#define MOUNTED                 -18
#define UMOUNTED                -19
#define MOUNTBUSY               -20
#define FCB_EMPTY               -21
#define HND_EMPTY               -22
#define BAD_HND                 -23
#define BAD_MODE                -24
#define SEEK_OVER               -25
#define FSYS_DIFF               -26
#define CUR_DIR                 -27
#define BAD_CMD                 -28
#define NOT_FMT                 -29
#define NO_MEM                  -30
#define IO_BUSY                 -31
#define FILE_EXIST              -32
#define BAD_FAT                 -33
#define DIR_FULL                -34
#define DISK_FULL               -35
#define BAD_EXE                 -36
#define KEEP_PR                 -37
#define WRITE_PRO               -38
#define NOT_RDY                 -39
#define SEC_NFND                -40
#define CRC_ERROR               -41
#define OVER_RUN                -42

Structures

typedef struct fsys {
        unsigned char name[16];
        int (* dev_call)();
        void *dev_type;
        long access_f;
        struct fsys *back;
        struct fsys *next;
        int path_len;
        unsigned char path[128];
} FSYS;

typedef struct filesbf {
        int fsys_flg;
        FSYS *fsysp;
        unsigned char temp[64];
        long fsize;
        long ftime;
        int atr;
        unsigned char path[128];
        unsigned char *name;
        unsigned char *upath;
        int name_max;
} FILESBF;

typedef struct dpb {
        int dev_id;                                     /* SCSI_ID or hnd */
        long rec_offset;                        /* record offset */
        int rec_sft;                            /* dos_record -> bios_rec */
        int sft_byt;                            /* bios_rec -> bytes */
        int (* dev_call)();                     /* device i/o job */
        unsigned short ej_flg;          /* eject ok(=1) ng(=0) flg */
        unsigned short secsiz;          /* Bytes per sector */
        unsigned char secsft;           /* Bytes per sector sft count */
        unsigned char clsiz;            /* Sector per Cluster */
        unsigned char clsft;            /* Sector per Cluster  sft count */
        unsigned char mid;                      /* Media descriptor */
        unsigned long fattop;           /* fat top sector */
        unsigned char nfat;                     /* Number of FAT tables */
        unsigned char fatlen;           /* Sectors in FAT */
        unsigned short fat_max;         /* fat data max 2-??? */
        unsigned long dirtop;           /* root dir top sector */
        unsigned short dircnt;          /* root dir entrys per sector */
        unsigned short dirlen;          /* root dir sectors */
        unsigned long datatop;          /* data top sector */
        long free_fat;                          /* free fat count (-1=no calc) */
        unsigned short new_fat;         /* last access new fat */
        unsigned short def_fat;         /* curdir fat(root=0) */
        unsigned char def_dir[64];      /* curdir dir name(root="") */
} DPB ;

typedef struct bpb {
        unsigned short secsiz;          /* Bytes per sector */
        unsigned char clsiz;            /* Cluster size */
        unsigned char nfat;                     /* Number of FAT tables */
        unsigned short nrsvsect;        /* Number of reserved sectors */
        unsigned short dirents;         /* Number of root directory entry */
        unsigned short maxsect;         /* Total sectors on disk */
        unsigned char mid;                      /* Media descriptor */
        unsigned char fatlen;           /* Sectors in FAT */
        unsigned long bigsect;          /* big total sectors (valid maxsect zero) */
        unsigned short nsect;           /* Sectors/track */
        unsigned short nheads;          /* Heads */
        unsigned long nhs;                      /* number of hidden sectors */
} BPB ;

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Functions

ID	Function Definition	Description
0	int fsys_init(unsigned char *, unsigned char *, int (*error_trap)());	{{{desc}}}
1	int fsys_mount(unsigned char *, FSYS *);	{{{desc}}}
2	int fsys_ctrl(unsigned char *, int, unsigned char *, int);	{{{desc}}}
3	FSYS *fsys_getfsys(unsigned char *);	{{{desc}}}
4	int fsys_format(unsigned char *, unsigned char *);	{{{desc}}}
5	long fsys_diskfree(unsigned char *);	{{{desc}}}
6	long fsys_getblocks(unsigned char *);	{{{desc}}}
7	int fsys_open(unsigned char *, int);	{{{desc}}}
8	int fsys_read(int, unsigned char *, int);	{{{desc}}}
9	int fsys_write(int, unsigned char *, int);	{{{desc}}}
10	long fsys_seek(int, long, int);	{{{desc}}}
11	long fsys_htime(int, long);	{{{desc}}}
12	int fsys_close(int);	{{{desc}}}
13	int fsys_delete(unsigned char *);	{{{desc}}}
14	int fsys_rename(unsigned char *, unsigned char *);	{{{desc}}}
15	int fsys_mkdir(unsigned char *);	{{{desc}}}
16	int fsys_rmdir(unsigned char *);	{{{desc}}}
17	int fsys_chdir(unsigned char *);	{{{desc}}}
18	int fsys_curdir(unsigned char *);	{{{desc}}}
19	int fsys_ffiles(FILESBF *, unsigned char *);	{{{desc}}}
20	int fsys_nfiles(FILESBF *);	{{{desc}}}
21	int fsys_efiles(FILESBF *);	{{{desc}}}
22	unsigned long fsys_datetime(unsigned long);	{{{desc}}}
23	int fsys_m_init(unsigned char *, unsigned char *);	{{{desc}}}
24	void *fsys_malloc(int);	{{{desc}}}
25	int fsys_free(void *);	{{{desc}}}
26	int fsys_setblock(char *, int);	{{{desc}}}

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Information copied and transcribed from header files by saga/HyperClub (APC-Project).