kernel/vfs/vfs.asm

   1 ;----------------------------------------------------------;
   2 ; BOS kernel                Christoffer Bubach, 2012-2015. ;
   3 ;----------------------------------------------------------;
   4 ;                                                          ;
   5 ;        VFS handling all devices and filesystems.         ;
   6 ;                                                          ;
   7 ;----------------------------------------------------------;
   8
   9
  10     ;---------------------------------------------;
  11     ;   VFS main structure                        ;
  12     ;---------------------------------------------;
  13     struc VFS
  14     {
  15         .number:                times 255      db 0   ; 00=FD, 0x10=HD, 0x60=CD, 0x80=VD, 90=RD, B0=ND
  16         .storage:
  17             times 255 * sizeof.VFS_storage     db 0   ; storage driver structure
  18         .filesystem:
  19             times 255 * sizeof.VFS_filesystem  db 0   ; filesystem driver structure
  20     }
  21
  22     virtual at 0                                      ; could use "at esi" instead
  23         VFS VFS
  24         sizeof.VFS = $-$$
  25     end virtual
  26
  27     ;---------------------------------------------;
  28     ;   VFS storage driver structure              ;
  29     ;---------------------------------------------;
  30     struc VFS_storage
  31     {
  32         .data_pointer         dd  0                   ; internal driver data
  33         .init                 dd  0                   ; pointer to init
  34         .deinit               dd  0                   ; remove driver
  35         .read                 dd  0                   ; read device
  36         .write                dd  0                   ; write device
  37         .ioctl                dd  0                   ; handle device specific extras
  38     }
  39
  40     virtual at 0
  41         VFS_storage VFS_storage
  42         sizeof.VFS_storage = $-$$
  43     end virtual
  44
  45     ;---------------------------------------------;
  46     ;   VFS filesystem structure                  ;
  47     ;---------------------------------------------;
  48     struc VFS_filesystem
  49     {
  50         .data_pointer         dd  0                   ; internal driver data
  51         .init                 dd  0                   ; pointer to init
  52         .deinit               dd  0                   ; remove driver
  53         .format               dd  0                   ; format drive
  54         .mount                dd  0                   ; mount drive
  55         .unmount              dd  0                   ; unmount drive
  56         .find                 dd  0                   ; find file
  57         .findnext             dd  0                   ; get next match
  58         .open                 dd  0                   ; open file, get handle
  59         .read                 dd  0                   ; read file from handle
  60         .write                dd  0                   ; write file from handle
  61         .seek                 dd  0                   ; seek from handle
  62         .remove               dd  0                   ; remove file/dir
  63         .create               dd  0                   ; create file/dir
  64         .ioctl                dd  0                   ; extra calls if exists
  65     }
  66
  67     virtual at 0
  68         VFS_filesystem VFS_filesystem
  69         sizeof.VFS_filesystem = $-$$
  70     end virtual
  71
  72     ;---------------------------------------------;
  73     ;   VFS structure pointer                     ;
  74     ;---------------------------------------------;
  75     VFS_structure             dd 0
  76
  77
  78 ;--------------------------------------------------------------;
  79 ;   init_vfs  -  detect connected drives                       ;
  80 ;--------------------------------------------------------------;
  81 ;                                                              ;
  82 ;       out:                    cf = set if failed             ;
  83 ;                                                              ;
  84 ;--------------------------------------------------------------;
  85 init_vfs:
  86         push   eax
  87         push   ebx
  88
  89         mov    ebx, sizeof.VFS                        ; allocate structure size
  90         call   allocate_mem
  91         cmp    eax, 0
  92         jne    .ok
  93         stc                                           ; if error, set carry
  94         mov    ebx, 0
  95
  96     .ok:
  97         mov    dword [VFS_structure], ebx
  98
  99         pop    ebx
 100         pop    eax
 101         ret
 102
 103 ;--------------------------------------------------------------;
 104 ;   add_media  -  add media driver                             ;
 105 ;--------------------------------------------------------------;
 106 ;                                                              ;
 107 ;       in:  reg = pointer to VFS drive info                   ;
 108 ;                                                              ;
 109 ;       out: reg = pointer to struct(s) if FAT12 found         ;
 110 ;                                                              ;
 111 ;--------------------------------------------------------------;
 112 add_media:
 113         push   eax
 114         ;...
 115         pop    eax
 116         ret
 117
 118 ;--------------------------------------------------------------;
 119 ;   add_fs  -  add filesystem driver                           ;
 120 ;--------------------------------------------------------------;
 121 ;                                                              ;
 122 ;       in:  reg = pointer to VFS drive info                   ;
 123 ;                                                              ;
 124 ;       out: reg = pointer to struct(s) if FAT12 found         ;
 125 ;                                                              ;
 126 ;--------------------------------------------------------------;
 127 add_fs:
 128         push   eax
 129         ;...
 130         pop    eax
 131         ret