Completed FAT12 structures, added some for VFS.

[BOS.git] / kernel / fat12 / fat12.asm

diff --git a/kernel/fat12/fat12.asm b/kernel/fat12/fat12.asm
index a96178245aba6e52c2d00cc61c1c300f730e0705..d7ad9cb1fa176f0ed997617dacff98f1e92af6ad 100644 (file)
--- a/kernel/fat12/fat12.asm
+++ b/kernel/fat12/fat12.asm
@@ -7,23 +7,30 @@
 ;----------------------------------------------------------;
 
     ;---------------------------------------------;
-    ;   main FAT12 info structure                 ;
+    ;   FAT12 main info structure                 ;
     ;---------------------------------------------;
     struc fat12
     {
-        .disk_number                     db  0       ; which VFS disk number
-        .root_dir                        dw  0       ; position of rootdir
-        .fat_1                           dd  0       ; position of fat1
-        .fat_2                           dd  0       ; position of fat2
-        .data_area                       dw  0       ; position of dataarea
-        .disk_size                       dd  0       ; total storage size
-        .free_space                      dd  0       ; free space available
-        .boot                            bootsector  
+        .disk_number                     db  0        ; which VFS disk number
+        .root_dir                        dw  0        ; position of rootdir
+        .fat_1                           dd  0        ; position of fat1
+        .fat_2                           dd  0        ; position of fat2
+        .data_area                       dw  0        ; position of dataarea
+        .disk_size                       dd  0        ; total storage size
+        .free_space                      dd  0        ; free space available
+        .boot: times sizeof.bootsector   db  0        ; copy of FAT12 bootsector
         .dir_entries:
-            times 16 * sizeof.dir_entry  db 0        ; 512b dir entry buffer
-        .fat_buffer:      times 512      db 0        ; 512b FAT cluster info buffer           
+            times 16 * sizeof.dir_entry  db  0        ; 512b dir entry buffer
+        .fat_buffer:      times 512      db  0        ; 512b FAT cluster info buffer
+        .filehandles:
+            times 32 * sizeof.filehandle db  0        ; for now, max opened files is 32
     }
 
+    virtual at 0                                      ; could use "at esi" instead
+        fat12 fat12
+        sizeof.fat12 = $-$$     
+    end virtual
+
     ;---------------------------------------------;
     ;   FAT12 bootsector structure                ;
     ;---------------------------------------------;
@@ -53,10 +60,15 @@
         .boot_signature    db  0,0                    ; 0x55,0xAA
     }
 
+    virtual at 0
+        bootsector bootsector
+        sizeof.bootsector = $-$$
+    end virtual
+
     ;---------------------------------------------;
     ;   FAT12 directory entry structure           ;
     ;---------------------------------------------;
-    struct dir_entry
+    struc dir_entry
     {
         .filename          db  0,0,0,0,0,0,0,0
         .extension         db  0,0,0
@@ -68,10 +80,15 @@
         .filesize          dd  0
     }
 
+    virtual at 0
+        dir_entry dir_entry
+        sizeof.dir_entry = $-$$
+    end virtual
+
     ;---------------------------------------------;
     ;   FAT12 directory entry for LFN             ;
     ;---------------------------------------------;
-    struct lnf_entry
+    struc lfn_entry
     {
         .order             db  0                      ; LFN entry in sequence, never 0x00 or 0xE5.
         .namefirst         dw  0,0,0,0,0              ; 5 first unicode (2byte) chars
@@ -85,22 +102,30 @@
 
     virtual at 0
         lfn_entry lfn_entry
-        sizeof.lfn_entry = $
-    end virtual
-
-    virtual at 0
-        dir_entry dir_entry
-        sizeof.dir_entry = $
+        sizeof.lfn_entry = $-$$
     end virtual
 
-    virtual at 0
-        bootsector bootsector
-        sizeof.bootsector = $
-    end virtual
+    ;---------------------------------------------;
+    ;   FAT12 file-handle structure               ;
+    ;---------------------------------------------;
+    struc filehandle
+    {
+        .handles           db  0                      ; reference count or or zero for unused
+        .mode              db  0                      ; open mode. 0=read, 1=write, 2=r/w.
+        .lfn_entry         dw  0                      ; file LFN directory entry position
+        .direntry          dw  0                      ; file directory entry position
+        .cluster           dw  0                      ; file first cluster
+        .attribute         db  0                      ; file attributes
+        .filetime          dw  0                      ; last modified time
+        .filedate          dw  0                      ; last modified date
+        .filesize          dd  0                      ; filesize
+        .position          dd  0                      ; R/W position in file
+        .clusterpos        dw  0                      ; cluster number of last cluster read
+    }
 
     virtual at 0
-        disk disk 
-        sizeof.disk = $     
+        filehandle filehandle
+        sizeof.filehandle = $-$$
     end virtual
 
     ;------------------------------------------;
@@ -138,13 +163,33 @@
 
 
 
-fd0: fat12            ; define fd0 data..  tmp example.
+fd0 fat12            ; define fd0 data..  tmp example.
 
 ; TODO, alloc memory for struct and keep pointer only.
 ; ---------------
 ;drive dd 0
 ;mov edi, drive+fat12into.boot
 
+;--------------------------------------
+; possible interface to copy/follow,
+; add getFilename/path function?
+;--------------------------------------
+;    INT 21,3C  Create file using handle
+;    INT 21,3D  Open file using handle
+;    INT 21,3E  Close file using handle
+;    INT 21,3F  Read file or device using handle
+;    INT 21,40  Write file or device using handle
+;    INT 21,41  Delete file
+;    INT 21,42  Move file pointer using handle
+;    INT 21,43  Change file mode
+;    INT 21,45  Duplicate file handle
+;    INT 21,46  Force duplicate file handle
+;    INT 21,56  Rename file
+;    INT 21,57  Get/set file date and time using handle
+;    INT 21,5A  Create temporary file (3.x+)
+;    INT 21,5B  Create new file (3.x+)
+;    INT 21,67  Set handle count (DOS 3.3+)
+
 ;--------------------------------------------------------------;
 ;   init_fat12  -  detect if drive fs is fat12 and init        ;
 ;--------------------------------------------------------------;
@@ -191,7 +236,10 @@ calc_lfn_chksum:
         mov    cx, 11
         xor    ax, ax                                 ; return value start with null
     .l1:
-        add    ax, byte [esi]                         ; add next char to sum
+        push   cx
+        movzx  cx, byte [esi]                         ; add next char to sum
+        add    ax, cx
+        pop    cx
         shr    ax, 1                                  ; shift sum right by 1
         inc    esi                                    ; prepare for next character
         loop   .l1