Subversion Repositories Kolibri OS

$Revision: 442 $

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;;                                                              ;;

;; Copyright (C) KolibriOS team 2004-2007. All rights reserved. ;;

;; Distributed under terms of the GNU General Public License    ;;

;;                                                              ;;

;; RAMDISK functions                                            ;;

;; (C) 2004 Ville Turjanmaa, License: GPL                       ;;

;; Addings by M.Lisovin                                         ;;

;; LFN support by diamond                                       ;;

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

; calculate fat chain

calculatefatchain:

   pushad

   mov  esi,RAMDISK+512

   mov  edi,RAMDISK_FAT

 fcnew:

   mov  eax,dword [esi]

   mov  ebx,dword [esi+4]

   mov  ecx,dword [esi+8]

   mov  edx,ecx

   shr  edx,4   ;8 ok

   shr  dx,4    ;7 ok

   xor  ch,ch

   shld ecx,ebx,20 ;6 ok

   shr  cx,4     ;5 ok

   shld ebx,eax,12

   and  ebx,0x0fffffff  ;4 ok

   shr  bx,4    ;3 ok

   shl  eax,4

   and  eax,0x0fffffff  ;2 ok

   shr  ax,4  ;1 ok

   mov  dword [edi],eax

   mov  dword [edi+4],ebx

   mov  dword [edi+8],ecx

   mov  dword [edi+12],edx

   add  edi,16

   add  esi,12

   cmp  edi,RAMDISK_FAT+2856*2   ;2849 clusters

   jnz  fcnew

   popad

   ret

restorefatchain:   ; restore fat chain

   pushad

   mov  esi,RAMDISK_FAT

   mov  edi,RAMDISK+512

  fcnew2:

   mov  eax,dword [esi]

   mov  ebx,dword [esi+4]

   shl  ax,4

   shl  eax,4

   shl  bx,4

   shr  ebx,4

   shrd eax,ebx,8

   shr  ebx,8

   mov  dword [edi],eax

   mov  word [edi+4],bx

   add  edi,6

   add  esi,8

   cmp  edi,RAMDISK+512+4278     ;4274 bytes - all used FAT

   jb   fcnew2

   mov  esi,RAMDISK+512           ; duplicate fat chain

   mov  edi,RAMDISK+512+0x1200

   mov  ecx,1069        ;4274/4

   cld

   rep  movsd

   popad

   ret

ramdisk_free_space:

;---------------------------------------------

;

; returns free space in edi

; rewr.by Mihasik

;---------------------------------------------

        push   eax ebx ecx

        mov  edi,RAMDISK_FAT ;start of FAT

        xor  ax,ax    ;Free cluster=0x0000 in FAT

        xor  ebx,ebx  ;counter

        mov  ecx,2849 ;2849 clusters

        cld

    rdfs1:

        repne scasw

        jnz  rdfs2    ;if last cluster not 0

        inc  ebx

        test    ecx, ecx

        jnz     rdfs1

    rdfs2:

        shl  ebx,9    ;free clusters*512

        mov  edi,ebx

        pop    ecx ebx eax

        ret

expand_filename:

;---------------------------------------------

;

; exapand filename with '.' to 11 character

; eax - pointer to filename

;---------------------------------------------

        push esi edi ebx

        mov  edi,esp                  ; check for '.' in the name

        add  edi,12+8

        mov  esi,eax

        mov  eax,edi

        mov  [eax+0],dword '    '

        mov  [eax+4],dword '    '

        mov  [eax+8],dword '    '

      flr1:

        cmp  [esi],byte '.'

        jne  flr2

        mov  edi,eax

        add  edi,7

        jmp  flr3

      flr2:

        mov  bl,[esi]

        mov  [edi],bl

      flr3:

        inc  esi

        inc  edi

        mov  ebx,eax

        add  ebx,11

        cmp  edi,ebx

        jbe  flr1

        pop  ebx edi esi

        ret

fileread:

;----------------------------------------------------------------

;

;  fileread - sys floppy

;

;  eax  points to filename 11 chars

;  ebx  first wanted block       ; 1+ ; if 0 then set to 1

;  ecx  number of blocks to read ; 1+ ; if 0 then set to 1

;  edx  mem location to return data

;  esi  length of filename 12*X 0=root

;

;  ret ebx = size or 0xffffffff file not found

;      eax = 0 ok read or other = errormsg

;

;--------------------------------------------------------------

        test   ebx,ebx ;if ebx=0 - set to 1

        jnz    frfl5

        inc    ebx

      frfl5:

        test   ecx,ecx ;if ecx=0 - set to 1

        jnz    frfl6

        inc    ecx

      frfl6:

        test   esi,esi          ; return ramdisk root

        jnz    fr_noroot        ;if not root

        cmp    ebx,14           ;14 clusters=root dir

        ja     oorr

        cmp    ecx,14

        ja     oorr

        jmp    fr_do

      oorr:

        mov    eax,5            ;out of root range (fnf)

        xor    ebx,ebx

        dec    ebx              ;0xffffffff

        ret

      fr_do:                    ;reading rootdir

        mov    edi,edx

        dec    ebx

        push   edx

        mov    edx,ecx

        add    edx,ebx

        cmp    edx,15     ;ebx+ecx=14+1

        pushf

        jbe    fr_do1

        sub    edx,14

        sub    ecx,edx

      fr_do1:

        shl    ebx,9

        mov    esi,RAMDISK+512*19

        add    esi,ebx

        shl    ecx,7

        cld

        rep    movsd

        popf

        pop    edx

        jae    fr_do2

        xor    eax,eax ; ok read

        xor    ebx,ebx

        ret

      fr_do2:        ;if last cluster

        mov    eax,6  ;end of file

        xor    ebx,ebx

        ret

     fr_noroot:

        sub    esp,32

        call   expand_filename

        dec    ebx

        push   eax

        push   eax ebx ecx edx esi edi

        call   rd_findfile

        je     fifound

        add    esp,32+28   ;if file not found

        ret

     fifound:

        mov    ebx,[edi-11+28]          ;file size

        mov    [esp+20],ebx

        mov    [esp+24],ebx

        add    edi,0xf

        movzx  eax,word [edi]

        mov    edi,eax                  ;edi=cluster

      frnew: