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