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kolibrios/kernel/branches/Kolibri-A/trunk/blkdev/rd.inc

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Embedded KOS (AMD/HT version) git-svn-id: svn://kolibrios.org@1505 a494cfbc-eb01-0410-851d-a64ba20cac60
2010-06-25 18:47:51 +02:00
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; 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 ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision$
; 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:
add eax,31 ;bootsector+2*fat+filenames
shl eax,9 ;*512
add eax,RAMDISK ;image base
mov ebx,[esp+8]
mov ecx,512 ;[esp+4]
cmp [esp+16],dword 0 ; wanted cluster ?
jne frfl7
call memmove
add [esp+8],dword 512
dec dword [esp+12] ; last wanted cluster ?
je frnoread
jmp frfl8
frfl7:
dec dword [esp+16]
frfl8:
movzx eax,word [edi*2+RAMDISK_FAT] ; find next cluster from FAT
mov edi,eax
cmp edi,4095 ;eof - cluster
jz frnoread2
cmp [esp+24],dword 512 ;eof - size
jb frnoread
sub [esp+24],dword 512
jmp frnew
frnoread2:
cmp [esp+16],dword 0 ; eof without read ?
je frnoread
pop edi esi edx ecx
add esp,4
pop ebx ; ebx <- eax : size of file
add esp,36
mov eax,6 ; end of file
ret
frnoread:
pop edi esi edx ecx
add esp,4
pop ebx ; ebx <- eax : size of file
add esp,36
xor eax,eax ;read ok
ret
rd_findfile:
;by Mihasik
;IN: eax - pointer to filename OUT: filestring+11 in edi or notZero in flags and fnf in eax,ebx
mov edi,RAMDISK+512*18+512 ;Point at directory
cld
rd_newsearch:
mov esi,eax
mov ecx,11
rep cmpsb
je rd_ff
add cl,21
add edi,ecx
cmp edi,RAMDISK+512*33
jb rd_newsearch
mov eax,5 ;if file not found - eax=5
xor ebx,ebx
dec ebx ;ebx=0xffffffff and zf=0
rd_ff:
ret
; \begin{diamond}
uni2ansi_str:
; convert UNICODE zero-terminated string to ASCII-string (codepage 866)
; in: esi->source, edi->buffer (may be esi=edi)
; destroys: eax,esi,edi
lodsw
test ax, ax
jz .done
cmp ax, 0x80
jb .ascii
cmp ax, 0x401
jz .yo1
cmp ax, 0x451
jz .yo2
cmp ax, 0x410
jb .unk
cmp ax, 0x440
jb .rus1
cmp ax, 0x450
jb .rus2
.unk:
mov al, '_'
jmp .doit
.yo1:
mov al, '<27>'
jmp .doit
.yo2:
mov al, '<27>'
jmp .doit
.rus1:
; 0x410-0x43F -> 0x80-0xAF
add al, 0x70
jmp .doit
.rus2:
; 0x440-0x44F -> 0xE0-0xEF
add al, 0xA0
.ascii:
.doit:
stosb
jmp uni2ansi_str
.done:
mov byte [edi], 0
ret
ansi2uni_char:
; convert ANSI character in al to UNICODE character in ax, using cp866 encoding
mov ah, 0
; 0x00-0x7F - trivial map
cmp al, 0x80
jb .ret
; 0x80-0xAF -> 0x410-0x43F
cmp al, 0xB0
jae @f
add ax, 0x410-0x80
.ret:
ret
@@:
; 0xE0-0xEF -> 0x440-0x44F
cmp al, 0xE0
jb .unk
cmp al, 0xF0
jae @f
add ax, 0x440-0xE0
ret
; 0xF0 -> 0x401
; 0xF1 -> 0x451
@@:
cmp al, '<27>'
jz .yo1
cmp al, '<27>'
jz .yo2
.unk:
mov al, '_' ; ah=0
ret
.yo1:
mov ax, 0x401
ret
.yo2:
mov ax, 0x451
ret
char_toupper:
; convert character to uppercase, using cp866 encoding
; in: al=symbol
; out: al=converted symbol
cmp al, 'a'
jb .ret
cmp al, 'z'
jbe .az
cmp al, '<27>'
jz .yo1
cmp al, '<27>'
jb .ret
cmp al, '<27>'
jb .rus1
cmp al, '<27>'
ja .ret
; 0xE0-0xEF -> 0x90-0x9F
sub al, '<27>'-'<27>'
.ret:
ret
.rus1:
; 0xA0-0xAF -> 0x80-0x8F
.az:
and al, not 0x20
ret
.yo1:
; 0xF1 -> 0xF0
dec ax
ret
fat_get_name:
; in: edi->FAT entry
; out: CF=1 - no valid entry
; else CF=0 and ebp->ASCIIZ-name
; (maximum length of filename is 255 (wide) symbols without trailing 0,
; but implementation requires buffer 261 words)
; destroys eax
cmp byte [edi], 0
jz .no
cmp byte [edi], 0xE5
jnz @f
.no:
stc
ret
@@:
cmp byte [edi+11], 0xF
jz .longname
test byte [edi+11], 8
jnz .no
push ecx
push edi ebp
test byte [ebp-4], 1
jnz .unicode_short
mov eax, [edi]
mov ecx, [edi+4]
mov [ebp], eax
mov [ebp+4], ecx
mov ecx, 8
@@:
cmp byte [ebp+ecx-1], ' '
loope @b
mov eax, [edi+8]
cmp al, ' '
je .done
shl eax, 8
mov al, '.'
lea ebp, [ebp+ecx+1]
mov [ebp], eax
mov ecx, 3
@@:
rol eax, 8
cmp al, ' '
jne .done
loop @b
dec ebp
.done:
and byte [ebp+ecx+1], 0 ; CF=0
pop ebp edi ecx
ret
.unicode_short:
mov ecx, 8
push ecx
@@:
mov al, [edi]
inc edi
call ansi2uni_char
mov [ebp], ax
inc ebp
inc ebp
loop @b
pop ecx
@@:
cmp word [ebp-2], ' '
jnz @f
dec ebp
dec ebp
loop @b
@@:
mov word [ebp], '.'
inc ebp
inc ebp
mov ecx, 3
push ecx
@@:
mov al, [edi]
inc edi
call ansi2uni_char
mov [ebp], ax
inc ebp
inc ebp
loop @b
pop ecx
@@:
cmp word [ebp-2], ' '
jnz @f
dec ebp
dec ebp
loop @b
dec ebp
dec ebp
@@:
and word [ebp], 0 ; CF=0
pop ebp edi ecx
ret
.longname:
; LFN
mov al, byte [edi]
and eax, 0x3F
dec eax
cmp al, 20
jae .no ; ignore invalid entries
mov word [ebp+260*2], 0 ; force null-terminating for orphans
imul eax, 13*2
add ebp, eax
test byte [edi], 0x40
jz @f
mov word [ebp+13*2], 0
@@:
push eax
; now copy name from edi to ebp ...
mov eax, [edi+1]
mov [ebp], eax ; symbols 1,2
mov eax, [edi+5]
mov [ebp+4], eax ; 3,4
mov eax, [edi+9]
mov [ebp+8], ax ; 5
mov eax, [edi+14]
mov [ebp+10], eax ; 6,7
mov eax, [edi+18]
mov [ebp+14], eax ; 8,9
mov eax, [edi+22]
mov [ebp+18], eax ; 10,11
mov eax, [edi+28]
mov [ebp+22], eax ; 12,13
; ... done
pop eax
sub ebp, eax
test eax, eax
jz @f
; if this is not first entry, more processing required
stc
ret
@@:
; if this is first entry:
test byte [ebp-4], 1
jnz .ret
; buffer at ebp contains UNICODE name, convert it to ANSI
push esi edi
mov esi, ebp
mov edi, ebp
call uni2ansi_str
pop edi esi
.ret:
clc
ret
fat_compare_name:
; compares ASCIIZ-names, case-insensitive (cp866 encoding)
; in: esi->name, ebp->name
; out: if names match: ZF=1 and esi->next component of name
; else: ZF=0, esi is not changed
; destroys eax
push ebp esi
.loop:
mov al, [ebp]
inc ebp
call char_toupper
push eax
lodsb
call char_toupper
cmp al, [esp]
jnz .done
pop eax
test al, al
jnz .loop
dec esi
pop eax
pop ebp
xor eax, eax ; set ZF flag
ret
.done:
cmp al, '/'
jnz @f
cmp byte [esp], 0
jnz @f
mov [esp+4], esi
@@:
pop eax
pop esi ebp
ret
fat_time_to_bdfe:
; in: eax=FAT time
; out: eax=BDFE time
push ecx edx
mov ecx, eax
mov edx, eax
shr eax, 11
shl eax, 16 ; hours
and edx, 0x1F
add edx, edx
mov al, dl ; seconds
shr ecx, 5
and ecx, 0x3F
mov ah, cl ; minutes
pop edx ecx
ret
fat_date_to_bdfe:
push ecx edx
mov ecx, eax
mov edx, eax
shr eax, 9
add ax, 1980
shl eax, 16 ; year
and edx, 0x1F
mov al, dl ; day
shr ecx, 5
and ecx, 0xF
mov ah, cl ; month
pop edx ecx
ret
bdfe_to_fat_time:
push edx
mov edx, eax
shr eax, 16
and dh, 0x3F
shl eax, 6
or al, dh
shr dl, 1
and dl, 0x1F
shl eax, 5
or al, dl
pop edx
ret
bdfe_to_fat_date:
push edx
mov edx, eax
shr eax, 16
sub ax, 1980
and dh, 0xF
shl eax, 4
or al, dh
and dl, 0x1F
shl eax, 5
or al, dl
pop edx
ret
fat_entry_to_bdfe:
; convert FAT entry at edi to BDFE (block of data of folder entry) at esi, advance esi
; destroys eax
mov eax, [ebp-4]
mov [esi+4], eax ; ASCII/UNICODE name
fat_entry_to_bdfe2:
movzx eax, byte [edi+11]
mov [esi], eax ; attributes
movzx eax, word [edi+14]
call fat_time_to_bdfe
mov [esi+8], eax ; creation time
movzx eax, word [edi+16]
call fat_date_to_bdfe
mov [esi+12], eax ; creation date
and dword [esi+16], 0 ; last access time is not supported on FAT
movzx eax, word [edi+18]
call fat_date_to_bdfe
mov [esi+20], eax ; last access date
movzx eax, word [edi+22]
call fat_time_to_bdfe
mov [esi+24], eax ; last write time
movzx eax, word [edi+24]
call fat_date_to_bdfe
mov [esi+28], eax ; last write date
mov eax, [edi+28]
mov [esi+32], eax ; file size (low dword)
xor eax, eax
mov [esi+36], eax ; file size (high dword)
test ebp, ebp
jz .ret
push ecx edi
lea edi, [esi+40]
mov esi, ebp
test byte [esi-4], 1
jz .ansi
mov ecx, 260/2
rep movsd
mov [edi-2], ax
@@:
mov esi, edi
pop edi ecx
.ret:
ret
.ansi:
mov ecx, 264/4
rep movsd
mov [edi-1], al
jmp @b
bdfe_to_fat_entry:
; convert BDFE at edx to FAT entry at edi
; destroys eax
; attributes byte
test byte [edi+11], 8 ; volume label?
jnz @f
mov al, [edx]
and al, 0x27
and byte [edi+11], 0x10
or byte [edi+11], al
@@:
mov eax, [edx+8]
call bdfe_to_fat_time
mov [edi+14], ax ; creation time
mov eax, [edx+12]
call bdfe_to_fat_date
mov [edi+16], ax ; creation date
mov eax, [edx+20]
call bdfe_to_fat_date
mov [edi+18], ax ; last access date
mov eax, [edx+24]
call bdfe_to_fat_time
mov [edi+22], ax ; last write time
mov eax, [edx+28]
call bdfe_to_fat_date
mov [edi+24], ax ; last write date
ret
ramdisk_root_first:
mov edi, RAMDISK+512*19
clc
ret
ramdisk_root_next:
add edi, 0x20
cmp edi, RAMDISK+512*33
cmc
ret
ramdisk_root_extend_dir:
stc
ret
uglobal
; this is for delete support
rd_prev_sector dd ?
rd_prev_prev_sector dd ?
endg
ramdisk_notroot_next:
add edi, 0x20
test edi, 0x1FF
jz ramdisk_notroot_next_sector
ret ; CF=0
ramdisk_notroot_next_sector:
push ecx
mov ecx, [eax]
push [rd_prev_sector]
pop [rd_prev_prev_sector]
mov [rd_prev_sector], ecx
mov ecx, [ecx*2+RAMDISK_FAT]
and ecx, 0xFFF
cmp ecx, 2849
jae ramdisk_notroot_first.err2
mov [eax], ecx
pop ecx
ramdisk_notroot_first:
mov eax, [eax]
cmp eax, 2
jb .err
cmp eax, 2849
jae .err
shl eax, 9
lea edi, [eax+(31 shl 9)+RAMDISK]
clc
ret
.err2:
pop ecx
.err:
stc
ret
ramdisk_notroot_next_write:
test edi, 0x1FF
jz ramdisk_notroot_next_sector
ramdisk_root_next_write:
ret
ramdisk_notroot_extend_dir:
pusha
xor eax, eax
mov edi, RAMDISK_FAT
mov ecx, 2849
repnz scasw
jnz .notfound
mov word [edi-2], 0xFFF
sub edi, RAMDISK_FAT
shr edi, 1
dec edi
mov eax, [esp+28]
mov ecx, [eax]
mov [RAMDISK_FAT+ecx*2], di
mov [eax], edi
shl edi, 9
add edi, (31 shl 9)+RAMDISK
mov [esp], edi
xor eax, eax
mov ecx, 128
rep stosd
popa
clc
ret
.notfound:
popa
stc
ret
rd_find_lfn:
; in: esi+ebp -> name
; out: CF=1 - file not found
; else CF=0 and edi->direntry
push esi edi
push 0
push ramdisk_root_first
push ramdisk_root_next
.loop:
call fat_find_lfn
jc .notfound
cmp byte [esi], 0
jz .found
.continue:
test byte [edi+11], 10h
jz .notfound
movzx eax, word [edi+26]
mov [esp+8], eax
mov dword [esp+4], ramdisk_notroot_first
mov dword [esp], ramdisk_notroot_next
test eax, eax
jnz .loop
mov dword [esp+4], ramdisk_root_first
mov dword [esp], ramdisk_notroot_next
jmp .loop
.notfound:
add esp, 12
pop edi esi
stc
ret
.found:
test ebp, ebp
jz @f
mov esi, ebp
xor ebp, ebp
jmp .continue
@@:
mov eax, [esp+8]
add esp, 16 ; CF=0
pop esi
ret
;----------------------------------------------------------------
;
; fs_RamdiskRead - LFN variant for reading sys floppy
;
; esi points to filename
; ebx pointer to 64-bit number = first wanted byte, 0+
; may be ebx=0 - start from first byte
; ecx number of bytes to read, 0+
; edx mem location to return data
;
; ret ebx = bytes read or 0xffffffff file not found
; eax = 0 ok read or other = errormsg
;
;--------------------------------------------------------------
fs_RamdiskRead:
cmp byte [esi], 0
jnz @f
or ebx, -1
mov eax, 10 ; access denied
ret
@@:
push edi
call rd_find_lfn
jnc .found
pop edi
or ebx, -1
mov eax, 5 ; file not found
ret
.found:
test ebx, ebx
jz .l1
cmp dword [ebx+4], 0
jz @f
xor ebx, ebx
.reteof:
mov eax, 6 ; EOF
pop edi
ret
@@:
mov ebx, [ebx]
.l1:
push ecx edx
push 0
mov eax, [edi+28]
sub eax, ebx
jb .eof
cmp eax, ecx
jae @f
mov ecx, eax
mov byte [esp], 6 ; EOF
@@:
movzx edi, word [edi+26] ; cluster
.new:
jecxz .done
test edi, edi
jz .eof
cmp edi, 0xFF8
jae .eof
lea eax, [edi+31] ; bootsector+2*fat+filenames
shl eax, 9 ; *512
add eax, RAMDISK ; image base
; now eax points to data of cluster
sub ebx, 512
jae .skip
lea eax, [eax+ebx+512]
neg ebx
push ecx
cmp ecx, ebx
jbe @f
mov ecx, ebx
@@:
mov ebx, edx
call memmove
add edx, ecx
sub [esp], ecx
pop ecx
xor ebx, ebx
.skip:
movzx edi, word [edi*2+RAMDISK_FAT] ; find next cluster from FAT
jmp .new
.eof:
mov ebx, edx
pop eax edx ecx
sub ebx, edx
jmp .reteof
.done:
mov ebx, edx
pop eax edx ecx edi
sub ebx, edx
ret
;----------------------------------------------------------------
;
; fs_RamdiskReadFolder - LFN variant for reading sys floppy folder
;
; esi points to filename; only root is folder on ramdisk
; ebx pointer to structure 32-bit number = first wanted block
; & flags (bitfields)
; flags: bit 0: 0=ANSI names, 1=UNICODE names
; ecx number of blocks to read, 0+
; edx mem location to return data
;
; ret ebx = size or 0xffffffff file not found
; eax = 0 ok read or other = errormsg
;
;--------------------------------------------------------------
fs_RamdiskReadFolder:
push edi
cmp byte [esi], 0
jz .root
call rd_find_lfn
jnc .found
pop edi
or ebx, -1
mov eax, ERROR_FILE_NOT_FOUND
ret
.found:
test byte [edi+11], 0x10
jnz .found_dir
pop edi
or ebx, -1
mov eax, ERROR_ACCESS_DENIED
ret
.found_dir:
movzx eax, word [edi+26]
add eax, 31
push 0
jmp .doit
.root:
mov eax, 19
push 14
.doit:
push esi ecx ebp
sub esp, 262*2 ; reserve space for LFN
mov ebp, esp
push dword [ebx+4] ; for fat_get_name: read ANSI/UNICODE names
mov ebx, [ebx]
; init header
push eax ecx
mov edi, edx
mov ecx, 32/4
xor eax, eax
rep stosd
mov byte [edx], 1 ; version
pop ecx eax
mov esi, edi ; esi points to block of data of folder entry (BDFE)
.main_loop:
mov edi, eax
shl edi, 9
add edi, RAMDISK
push eax
.l1:
call fat_get_name
jc .l2
cmp byte [edi+11], 0xF
jnz .do_bdfe
add edi, 0x20
test edi, 0x1FF
jnz .do_bdfe
pop eax
inc eax
dec byte [esp+262*2+16]
jz .done
jns @f
; read next sector from FAT
mov eax, [(eax-31-1)*2+RAMDISK_FAT]
and eax, 0xFFF
cmp eax, 0xFF8
jae .done
add eax, 31
mov byte [esp+262*2+16], 0
@@:
mov edi, eax
shl edi, 9
add edi, RAMDISK
push eax
.do_bdfe:
inc dword [edx+8] ; new file found
dec ebx
jns .l2
dec ecx
js .l2
inc dword [edx+4] ; new file block copied
call fat_entry_to_bdfe
.l2:
add edi, 0x20
test edi, 0x1FF
jnz .l1
pop eax
inc eax
dec byte [esp+262*2+16]
jz .done
jns @f
; read next sector from FAT
mov eax, [(eax-31-1)*2+RAMDISK_FAT]
and eax, 0xFFF
cmp eax, 0xFF8
jae .done
add eax, 31
mov byte [esp+262*2+16], 0
@@:
jmp .main_loop
.done:
add esp, 262*2+4
pop ebp
mov ebx, [edx+4]
xor eax, eax
dec ecx
js @f
mov al, ERROR_END_OF_FILE
@@:
pop ecx esi edi edi
ret
iglobal
label fat_legal_chars byte
; 0 = not allowed
; 1 = allowed only in long names
; 3 = allowed
times 32 db 0
; ! " # $ % & ' ( ) * + , - . /
db 1,3,0,3,3,3,3,3,3,3,0,1,1,3,3,0
; 0 1 2 3 4 5 6 7 8 9 : ; < = > ?
db 3,3,3,3,3,3,3,3,3,3,0,1,0,1,0,0
; @ A B C D E F G H I J K L M N O
db 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3
; P Q R S T U V W X Y Z [ \ ] ^ _
db 3,3,3,3,3,3,3,3,3,3,3,1,0,1,3,3
; ` a b c d e f g h i j k l m n o
db 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3
; p q r s t u v w x y z { | } ~
db 3,3,3,3,3,3,3,3,3,3,3,3,0,3,3,0
endg
fat_name_is_legal:
; in: esi->(long) name
; out: CF set <=> legal
; destroys eax
push esi
xor eax, eax
@@:
lodsb
test al, al
jz .done
cmp al, 80h
jae .big
test [fat_legal_chars+eax], 1
jnz @b
.err:
pop esi
clc
ret
.big:
; 0x80-0xAF, 0xE0-0xEF
cmp al, 0xB0
jb @b
cmp al, 0xE0
jb .err
cmp al, 0xF0
jb @b
jmp .err
.done:
sub esi, [esp]
cmp esi, 257
pop esi
ret
fat_next_short_name:
; in: edi->8+3 name
; out: name corrected
; CF=1 <=> error
pushad
mov ecx, 8
mov al, '~'
std
push edi
add edi, 7
repnz scasb
pop edi
cld
jz .tilde
; tilde is not found, insert "~1" at end
add edi, 6
cmp word [edi], ' '
jnz .insert_tilde
@@: dec edi
cmp byte [edi], ' '
jz @b
inc edi
.insert_tilde:
mov word [edi], '~1'
popad
clc
ret
.tilde:
push edi
add edi, 7
xor ecx, ecx
@@:
; after tilde may be only digits and trailing spaces
cmp byte [edi], '~'
jz .break
cmp byte [edi], ' '
jz .space
cmp byte [edi], '9'
jnz .found
dec edi
jmp @b
.space:
dec edi
inc ecx
jmp @b
.found:
inc byte [edi]
add dword [esp], 8
jmp .zerorest
.break:
jecxz .noplace
inc edi
mov al, '1'
@@:
xchg al, [edi]
inc edi
cmp al, ' '
mov al, '0'
jnz @b
.succ:
pop edi
popad
clc
ret
.noplace:
dec edi
cmp edi, [esp]
jz .err
add dword [esp], 8
mov word [edi], '~1'
inc edi
inc edi
@@:
mov byte [edi], '0'
.zerorest:
inc edi
cmp edi, [esp]
jb @b
pop edi
popad
;clc ; automatically
ret
.err:
pop edi
popad
stc
ret
fat_gen_short_name:
; in: esi->long name
; edi->buffer (8+3=11 chars)
; out: buffer filled
pushad
mov eax, ' '
push edi
stosd
stosd
stosd
pop edi
xor eax, eax
push 8
pop ebx
lea ecx, [edi+8]
.loop:
lodsb
test al, al
jz .done
call char_toupper
cmp al, ' '
jz .space
cmp al, 80h
ja .big
test [fat_legal_chars+eax], 2
jnz .symbol
.inv_symbol:
mov al, '_'
or bh, 1
.symbol:
cmp al, '.'
jz .dot
.normal_symbol:
dec bl
jns .store
mov bl, 0
.space:
or bh, 1
jmp .loop
.store:
stosb
jmp .loop
.big:
cmp al, 0xB0
jb .normal_symbol
cmp al, 0xE0
jb .inv_symbol
cmp al, 0xF0
jb .normal_symbol
jmp .inv_symbol
.dot:
test bh, 2
jz .firstdot
pop ebx
add ebx, edi
sub ebx, ecx
push ebx
cmp ebx, ecx
jb @f
pop ebx
push ecx
@@:
cmp edi, ecx
jbe .skip
@@:
dec edi
mov al, [edi]
dec ebx
mov [ebx], al
mov byte [edi], ' '
cmp edi, ecx
ja @b
.skip:
mov bh, 3
jmp @f
.firstdot:
cmp bl, 8
jz .space
push edi
or bh, 2
@@:
mov edi, ecx
mov bl, 3
jmp .loop
.done:
test bh, 2
jz @f
pop edi
@@:
lea edi, [ecx-8]
test bh, 1
jz @f
call fat_next_short_name
@@:
popad
ret
;----------------------------------------------------------------
;
; fs_RamdiskRewrite - LFN variant for writing ramdisk
; fs_RamdiskCreateFolder - create folder on ramdisk
;
; esi points to file/folder name
; ebx ignored (reserved)
; ecx number of bytes to write, 0+ (ignored for folders)
; edx mem location to data (ignored for folders)
;
; ret ebx = number of written bytes
; eax = 0 ok read or other = errormsg
;
;--------------------------------------------------------------
@@:
mov eax, ERROR_ACCESS_DENIED
xor ebx, ebx
ret
fs_RamdiskCreateFolder:
mov al, 1 ; create folder
jmp fs_RamdiskRewrite.common
fs_RamdiskRewrite:
xor eax, eax ; create file
.common:
cmp byte [esi], 0
jz @b
pushad
xor edi, edi
push esi
test ebp, ebp
jz @f
mov esi, ebp
@@:
lodsb
test al, al
jz @f
cmp al, '/'
jnz @b
lea edi, [esi-1]
jmp @b
@@:
pop esi
test edi, edi
jnz .noroot
test ebp, ebp
jnz .hasebp
push ramdisk_root_extend_dir
push ramdisk_root_next_write
push edi
push ramdisk_root_first
push ramdisk_root_next
jmp .common1
.hasebp:
mov eax, ERROR_ACCESS_DENIED
cmp byte [ebp], 0
jz .ret1
push ebp
xor ebp, ebp
call rd_find_lfn
pop esi
jc .notfound0
jmp .common0
.noroot:
mov eax, ERROR_ACCESS_DENIED
cmp byte [edi+1], 0
jz .ret1
; check existence
mov byte [edi], 0
push edi
call rd_find_lfn
pop esi
mov byte [esi], '/'
jnc @f
.notfound0:
mov eax, ERROR_FILE_NOT_FOUND
.ret1:
mov [esp+28], eax
popad
xor ebx, ebx
ret
@@:
inc esi
.common0:
test byte [edi+11], 0x10 ; must be directory
mov eax, ERROR_ACCESS_DENIED
jz .ret1
movzx ebp, word [edi+26] ; ebp=cluster
mov eax, ERROR_FAT_TABLE
cmp ebp, 2
jb .ret1
cmp ebp, 2849
jae .ret1
push ramdisk_notroot_extend_dir
push ramdisk_notroot_next_write
push ebp
push ramdisk_notroot_first
push ramdisk_notroot_next
.common1:
call fat_find_lfn
jc .notfound
; found
test byte [edi+11], 10h
jz .exists_file
; found directory; if we are creating directory, return OK,
; if we are creating file, say "access denied"
add esp, 20
popad
test al, al
mov eax, ERROR_ACCESS_DENIED
jz @f
mov al, 0
@@:
xor ebx, ebx
ret
.exists_file:
; found file; if we are creating directory, return "access denied",
; if we are creating file, delete existing file and continue
cmp byte [esp+20+28], 0
jz @f
add esp, 20
popad
mov eax, ERROR_ACCESS_DENIED
xor ebx, ebx
ret
@@:
; delete FAT chain
push edi
xor eax, eax
mov dword [edi+28], eax ; zero size
xchg ax, word [edi+26] ; start cluster
test eax, eax
jz .done1
@@:
cmp eax, 0xFF8
jae .done1
lea edi, [RAMDISK_FAT + eax*2] ; position in FAT
xor eax, eax
xchg ax, [edi]
jmp @b
.done1:
pop edi
call get_time_for_file
mov [edi+22], ax
call get_date_for_file
mov [edi+24], ax
mov [edi+18], ax
or byte [edi+11], 20h ; set 'archive' attribute
jmp .doit
.notfound:
; file is not found; generate short name
call fat_name_is_legal
jc @f
add esp, 20
popad
mov eax, ERROR_FILE_NOT_FOUND
xor ebx, ebx
ret
@@:
sub esp, 12
mov edi, esp
call fat_gen_short_name
.test_short_name_loop:
push esi edi ecx
mov esi, edi
lea eax, [esp+12+12+8]
mov [eax], ebp
call dword [eax-4]
jc .found
.test_short_name_entry:
cmp byte [edi+11], 0xF
jz .test_short_name_cont
mov ecx, 11
push esi edi
repz cmpsb
pop edi esi
jz .short_name_found
.test_short_name_cont:
lea eax, [esp+12+12+8]
call dword [eax-8]
jnc .test_short_name_entry
jmp .found
.short_name_found:
pop ecx edi esi
call fat_next_short_name
jnc .test_short_name_loop
.disk_full:
add esp, 12+20
popad
mov eax, ERROR_DISK_FULL
xor ebx, ebx
ret
.found:
pop ecx edi esi
; now find space in directory
; we need to save LFN <=> LFN is not equal to short name <=> generated name contains '~'
mov al, '~'
push ecx edi
mov ecx, 8
repnz scasb
push 1
pop eax ; 1 entry
jnz .notilde
; we need ceil(strlen(esi)/13) additional entries = floor((strlen(esi)+12+13)/13) total
xor eax, eax
@@:
cmp byte [esi], 0
jz @f
inc esi
inc eax
jmp @b
@@:
sub esi, eax
add eax, 12+13
mov ecx, 13
push edx
cdq
div ecx
pop edx
.notilde:
push -1
push -1
; find <eax> successive entries in directory
xor ecx, ecx
push eax
lea eax, [esp+12+8+12+8]
mov [eax], ebp
call dword [eax-4]
pop eax
.scan_dir:
cmp byte [edi], 0
jz .free
cmp byte [edi], 0xE5
jz .free
xor ecx, ecx
.scan_cont:
push eax
lea eax, [esp+12+8+12+8]
call dword [eax-8]
pop eax
jnc .scan_dir
push eax
lea eax, [esp+12+8+12+8]
call dword [eax+8] ; extend directory
pop eax
jnc .scan_dir
add esp, 8+8+12+20
popad
mov eax, ERROR_DISK_FULL
xor ebx, ebx
ret
.free:
test ecx, ecx
jnz @f
mov [esp], edi
mov ecx, [esp+8+8+12+8]
mov [esp+4], ecx
xor ecx, ecx
@@:
inc ecx
cmp ecx, eax
jb .scan_cont
; found!
; calculate name checksum
push esi ecx
mov esi, [esp+8+8]
mov ecx, 11
xor eax, eax
@@:
ror al, 1
add al, [esi]
inc esi
loop @b
pop ecx esi
pop edi
pop dword [esp+8+12+8]
; edi points to last entry in free chunk
dec ecx
jz .nolfn
push esi
push eax
mov al, 40h
.writelfn:
or al, cl
mov esi, [esp+4]
push ecx
dec ecx
imul ecx, 13
add esi, ecx
stosb
mov cl, 5
call .read_symbols
mov ax, 0xF
stosw
mov al, [esp+4]
stosb
mov cl, 6
call .read_symbols
xor eax, eax
stosw
mov cl, 2
call .read_symbols
pop ecx
lea eax, [esp+8+8+12+8]
call dword [eax+4] ; next write
xor eax, eax
loop .writelfn
pop eax
pop esi
.nolfn:
xchg esi, [esp]
mov ecx, 11
rep movsb
mov word [edi], 20h ; attributes
sub edi, 11
pop esi ecx
add esp, 12
mov byte [edi+13], 0 ; tenths of a second at file creation time
call get_time_for_file
mov [edi+14], ax ; creation time
mov [edi+22], ax ; last write time
call get_date_for_file
mov [edi+16], ax ; creation date
mov [edi+24], ax ; last write date
mov [edi+18], ax ; last access date
and word [edi+20], 0 ; high word of cluster
and word [edi+26], 0 ; low word of cluster - to be filled
and dword [edi+28], 0 ; file size - to be filled
cmp byte [esp+20+28], 0
jz .doit
; create directory
mov byte [edi+11], 10h ; attributes: folder
mov ecx, 32*2
mov edx, edi
.doit:
push edx
push ecx
push edi
add edi, 26 ; edi points to low word of cluster
push edi
jecxz .done
mov ecx, 2849
mov edi, RAMDISK_FAT
.write_loop:
; allocate new cluster
xor eax, eax
repnz scasw
jnz .disk_full2
dec edi
dec edi
; lea eax, [edi-(RAMDISK_FAT)]
mov eax, edi
sub eax, RAMDISK_FAT
shr eax, 1 ; eax = cluster
mov word [edi], 0xFFF ; mark as last cluster
xchg edi, [esp]
stosw
pop edi
push edi
inc ecx
; write data
cmp byte [esp+16+20+28], 0
jnz .writedir
shl eax, 9
add eax, RAMDISK+31*512
.writefile:
mov ebx, edx
xchg eax, ebx
push ecx
mov ecx, 512
cmp dword [esp+12], ecx
jae @f
mov ecx, [esp+12]
@@:
call memmove
add edx, ecx
sub [esp+12], ecx
pop ecx
jnz .write_loop
.done:
mov ebx, edx
pop edi edi ecx edx
sub ebx, edx
mov [edi+28], ebx
add esp, 20
mov [esp+16], ebx
popad
xor eax, eax
ret
.disk_full2:
mov ebx, edx
pop edi edi ecx edx
sub ebx, edx
mov [edi+28], ebx
add esp, 20
mov [esp+16], ebx
popad
push ERROR_DISK_FULL
pop eax
ret
.writedir:
mov edi, eax
shl edi, 9
add edi, RAMDISK+31*512
mov esi, edx
mov ecx, 32/4
push ecx
rep movsd
mov dword [edi-32], '. '
mov dword [edi-32+4], ' '
mov dword [edi-32+8], ' '
mov byte [edi-32+11], 10h
mov word [edi-32+26], ax
mov esi, edx
pop ecx
rep movsd
mov dword [edi-32], '.. '
mov dword [edi-32+4], ' '
mov dword [edi-32+8], ' '
mov byte [edi-32+11], 10h
mov eax, [esp+16+8]
mov word [edi-32+26], ax
xor eax, eax
mov ecx, (512-32*2)/4
rep stosd
pop edi edi ecx edx
add esp, 20
popad
xor eax, eax
xor ebx, ebx
ret
.read_symbol:
or ax, -1
test esi, esi
jz .retFFFF
lodsb
test al, al
jnz ansi2uni_char
xor eax, eax
xor esi, esi
.retFFFF:
ret
.read_symbols:
call .read_symbol
stosw
loop .read_symbols
ret
;----------------------------------------------------------------
;
; fs_RamdiskWrite - LFN variant for writing to sys floppy
;
; esi points to filename
; ebx pointer to 64-bit number = first wanted byte, 0+
; may be ebx=0 - start from first byte
; ecx number of bytes to write, 0+
; edx mem location to data
;
; ret ebx = bytes written (maybe 0)
; eax = 0 ok write or other = errormsg
;
;--------------------------------------------------------------
@@:
push ERROR_ACCESS_DENIED
fs_RamdiskWrite.ret0:
pop eax
xor ebx, ebx
ret
fs_RamdiskWrite:
cmp byte [esi], 0
jz @b
pushad
call rd_find_lfn
jnc .found
popad
push ERROR_FILE_NOT_FOUND
jmp .ret0
.found:
; must not be directory
test byte [edi+11], 10h
jz @f
popad
push ERROR_ACCESS_DENIED
jmp .ret0
@@:
; FAT does not support files larger than 4GB
test ebx, ebx
jz .l1
cmp dword [ebx+4], 0
jz @f
.eof:
popad
push ERROR_END_OF_FILE
jmp .ret0
@@:
mov ebx, [ebx]
.l1:
; now edi points to direntry, ebx=start byte to write,
; ecx=number of bytes to write, edx=data pointer
call fat_update_datetime
; extend file if needed
add ecx, ebx
jc .eof ; FAT does not support files larger than 4GB
push 0 ; return value=0
cmp ecx, [edi+28]
jbe .length_ok
cmp ecx, ebx
jz .length_ok
call ramdisk_extend_file
jnc .length_ok
; ramdisk_extend_file can return two error codes: FAT table error or disk full.
; First case is fatal error, in second case we may write some data
mov [esp], eax
cmp al, ERROR_DISK_FULL
jz .disk_full
pop eax
mov [esp+28], eax
popad
xor ebx, ebx
ret
.disk_full:
; correct number of bytes to write
mov ecx, [edi+28]
cmp ecx, ebx
ja .length_ok
.ret:
pop eax
mov [esp+28], eax ; eax=return value
sub edx, [esp+20]
mov [esp+16], edx ; ebx=number of written bytes
popad
ret
.length_ok:
; now ebx=start pos, ecx=end pos, both lie inside file
sub ecx, ebx
jz .ret
movzx edi, word [edi+26] ; starting cluster
.write_loop:
sub ebx, 0x200
jae .next_cluster
push ecx
neg ebx
cmp ecx, ebx
jbe @f
mov ecx, ebx
@@:
mov eax, edi
shl eax, 9
add eax, RAMDISK+31*512+0x200
sub eax, ebx
mov ebx, eax
mov eax, edx
call memmove
xor ebx, ebx
add edx, ecx
sub [esp], ecx
pop ecx
jz .ret
.next_cluster:
movzx edi, word [edi*2+RAMDISK_FAT]
jmp .write_loop
ramdisk_extend_file.zero_size:
xor eax, eax
jmp ramdisk_extend_file.start_extend
; extends file on ramdisk to given size, new data area is filled by 0
; in: edi->direntry, ecx=new size
; out: CF=0 => OK, eax=0
; CF=1 => error, eax=code (ERROR_FAT_TABLE or ERROR_DISK_FULL)
ramdisk_extend_file:
push ecx
; find the last cluster of file
movzx eax, word [edi+26] ; first cluster
mov ecx, [edi+28]
jecxz .zero_size
@@:
sub ecx, 0x200
jbe @f
mov eax, [eax*2+RAMDISK_FAT]
and eax, 0xFFF
jz .fat_err
cmp eax, 0xFF8
jb @b
.fat_err:
pop ecx
push ERROR_FAT_TABLE
pop eax
stc
ret
@@:
push eax
mov eax, [eax*2+RAMDISK_FAT]
and eax, 0xFFF
cmp eax, 0xFF8
pop eax
jb .fat_err
; set length to full number of sectors and make sure that last sector is zero-padded
sub [edi+28], ecx
push eax edi
mov edi, eax
shl edi, 9
lea edi, [edi+RAMDISK+31*512+0x200+ecx]
neg ecx
xor eax, eax
rep stosb
pop edi eax
.start_extend:
pop ecx
; now do extend
push edx esi
mov esi, RAMDISK_FAT+2*2 ; start scan from cluster 2
mov edx, 2847 ; number of clusters to scan
.extend_loop:
cmp [edi+28], ecx
jae .extend_done
; add new sector
push ecx
mov ecx, edx
push edi
mov edi, esi
jecxz .disk_full
push eax
xor eax, eax
repnz scasw
pop eax
jnz .disk_full
mov word [edi-2], 0xFFF
mov esi, edi
mov edx, ecx
sub edi, RAMDISK_FAT
shr edi, 1
dec edi ; now edi=new cluster
test eax, eax
jz .first_cluster
mov [RAMDISK_FAT+eax*2], di
jmp @f
.first_cluster:
pop eax ; eax->direntry
push eax
mov [eax+26], di
@@:
push edi
shl edi, 9
add edi, RAMDISK+31*512
xor eax, eax
mov ecx, 512/4
rep stosd
pop eax ; eax=new cluster
pop edi ; edi->direntry
pop ecx ; ecx=required size
add dword [edi+28], 0x200
jmp .extend_loop
.extend_done:
mov [edi+28], ecx
pop esi edx
xor eax, eax ; CF=0
ret
.disk_full:
pop edi ecx
pop esi edx
stc
push ERROR_DISK_FULL
pop eax
ret
fat_update_datetime:
call get_time_for_file
mov [edi+22], ax ; last write time
call get_date_for_file
mov [edi+24], ax ; last write date
mov [edi+18], ax ; last access date
ret
;----------------------------------------------------------------
;
; fs_RamdiskSetFileEnd - set end of file on ramdisk
;
; esi points to filename
; ebx points to 64-bit number = new file size
; ecx ignored (reserved)
; edx ignored (reserved)
;
; ret eax = 0 ok or other = errormsg
;
;--------------------------------------------------------------
fs_RamdiskSetFileEnd:
cmp byte [esi], 0
jnz @f
.access_denied:
push ERROR_ACCESS_DENIED
jmp .ret
@@:
push edi
call rd_find_lfn
jnc @f
pop edi
push ERROR_FILE_NOT_FOUND
.ret:
pop eax
ret
@@:
; must not be directory
test byte [edi+11], 10h
jz @f
pop edi
jmp .access_denied
@@:
; file size must not exceed 4Gb
cmp dword [ebx+4], 0
jz @f
pop edi
push ERROR_END_OF_FILE
jmp .ret
@@:
; set file modification date/time to current
call fat_update_datetime
mov eax, [ebx]
cmp eax, [edi+28]
jb .truncate
ja .expand
pop edi
xor eax, eax
ret
.expand:
push ecx
mov ecx, eax
call ramdisk_extend_file
pop ecx
pop edi
ret
.truncate:
mov [edi+28], eax
push ecx
movzx ecx, word [edi+26]
test eax, eax
jz .zero_size
; find new last sector
@@:
sub eax, 0x200
jbe @f
movzx ecx, word [RAMDISK_FAT+ecx*2]
jmp @b
@@:
; zero data at the end of last sector
push ecx
mov edi, ecx
shl edi, 9
lea edi, [edi+RAMDISK+31*512+eax+0x200]
mov ecx, eax
neg ecx
xor eax, eax
rep stosb
pop ecx
; terminate FAT chain
lea ecx, [RAMDISK_FAT+ecx+ecx]
push dword [ecx]
mov word [ecx], 0xFFF
pop ecx
and ecx, 0xFFF
jmp .delete
.zero_size:
and word [edi+26], 0
.delete:
; delete FAT chain starting with ecx
; mark all clusters as free
cmp ecx, 0xFF8
jae .deleted
lea ecx, [RAMDISK_FAT+ecx+ecx]
push dword [ecx]
and word [ecx], 0
pop ecx
and ecx, 0xFFF
jmp .delete
.deleted:
pop ecx
pop edi
xor eax, eax
ret
fs_RamdiskGetFileInfo:
cmp byte [esi], 0
jnz @f
mov eax, 2 ; unsupported
ret
@@:
push edi
call rd_find_lfn
fs_GetFileInfo_finish:
jnc @f
pop edi
mov eax, ERROR_FILE_NOT_FOUND
ret
@@:
push esi ebp
xor ebp, ebp
mov esi, edx
and dword [esi+4], 0
call fat_entry_to_bdfe2
pop ebp esi
pop edi
xor eax, eax
ret
fs_RamdiskSetFileInfo:
cmp byte [esi], 0
jnz @f
mov eax, 2 ; unsupported
ret
@@:
push edi
call rd_find_lfn
jnc @f
pop edi
mov eax, ERROR_FILE_NOT_FOUND
ret
@@:
call bdfe_to_fat_entry
pop edi
xor eax, eax
ret
;----------------------------------------------------------------
;
; fs_RamdiskDelete - delete file or empty folder from ramdisk
;
; esi points to filename
;
; ret eax = 0 ok or other = errormsg
;
;--------------------------------------------------------------
fs_RamdiskDelete:
cmp byte [esi], 0
jnz @f
; cannot delete root!
.access_denied:
push ERROR_ACCESS_DENIED
.pop_ret:
pop eax
ret
@@:
and [rd_prev_sector], 0
and [rd_prev_prev_sector], 0
push edi
call rd_find_lfn
jnc .found
pop edi
push ERROR_FILE_NOT_FOUND
jmp .pop_ret
.found:
cmp dword [edi], '. '
jz .access_denied2
cmp dword [edi], '.. '
jz .access_denied2
test byte [edi+11], 10h
jz .dodel
; we can delete only empty folders!
movzx eax, word [edi+26]
push ebx
mov ebx, eax
shl ebx, 9
add ebx, RAMDISK + 31*0x200 + 2*0x20
.checkempty:
cmp byte [ebx], 0
jz .empty
cmp byte [ebx], 0xE5
jnz .notempty
add ebx, 0x20
test ebx, 0x1FF
jnz .checkempty
movzx eax, word [RAMDISK_FAT + eax*2]
test eax, eax
jz .empty
mov ebx, eax
shl ebx, 9
add ebx, RAMDISK + 31*0x200
jmp .checkempty
.notempty:
pop ebx
.access_denied2:
pop edi
jmp .access_denied
.empty:
pop ebx
.dodel:
movzx eax, word [edi+26]
; delete folder entry
mov byte [edi], 0xE5
; delete LFN (if present)
.lfndel:
test edi, 0x1FF
jnz @f
cmp [rd_prev_sector], 0
jz @f
cmp [rd_prev_sector], -1
jz .lfndone
mov edi, [rd_prev_sector]
push [rd_prev_prev_sector]
pop [rd_prev_sector]
or [rd_prev_prev_sector], -1
shl edi, 9
add edi, RAMDISK + 31*0x200 + 0x200
@@:
sub edi, 0x20
cmp byte [edi], 0xE5
jz .lfndone
cmp byte [edi+11], 0xF
jnz .lfndone
mov byte [edi], 0xE5
jmp .lfndel
.lfndone:
; delete FAT chain
test eax, eax
jz .done
lea eax, [RAMDISK_FAT + eax*2]
push dword [eax]
and word [eax], 0
pop eax
and eax, 0xFFF
jmp .lfndone
.done:
pop edi
xor eax, eax
ret
; \end{diamond}
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