Subversion Repositories Kolibri OS

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;;                                                              ;;

;; Copyright (C) KolibriOS team 2004-2008. All rights reserved. ;;

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

;;                                                              ;;

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

$Revision: 897 $

image_of_eax EQU esp+36

image_of_ebx EQU esp+24

; System function 70 - files with long names (LFN)

; diamond, 2006

iglobal

; in this table names must be in lowercase

rootdirs:

	db	2,'rd'

	dd	fs_OnRamdisk

	dd	fs_NextRamdisk

	db	7,'ramdisk'

	dd	fs_OnRamdisk

	dd	fs_NextRamdisk

	db	2,'fd'

	dd	fs_OnFloppy

	dd	fs_NextFloppy

	db	10,'floppydisk'

	dd	fs_OnFloppy

	dd	fs_NextFloppy

	db	3,'hd0'

	dd	fs_OnHd0

	dd	fs_NextHd0

	db	3,'hd1'

	dd	fs_OnHd1

	dd	fs_NextHd1

	db	3,'hd2'

	dd	fs_OnHd2

	dd	fs_NextHd2

	db	3,'hd3'

	dd	fs_OnHd3

	dd	fs_NextHd3

;**********************************************

	db	3,'cd0'

	dd	fs_OnCd0

	dd	fs_NextCd

	db	3,'cd1'

	dd	fs_OnCd1

	dd	fs_NextCd

	db	3,'cd2'

	dd	fs_OnCd2

	dd	fs_NextCd

	db	3,'cd3'

	dd	fs_OnCd3

	dd	fs_NextCd

;***********************************************

	db	0

virtual_root_query:

	dd	fs_HasRamdisk

	db	'rd',0

	dd	fs_HasFloppy

	db	'fd',0

	dd	fs_HasHd0

	db	'hd0',0

	dd	fs_HasHd1

	db	'hd1',0

	dd	fs_HasHd2

	db	'hd2',0

	dd	fs_HasHd3

	db	'hd3',0

;**********************************************

	dd	fs_HasCd0

	db	'cd0',0

	dd	fs_HasCd1

	db	'cd1',0

	dd	fs_HasCd2

	db	'cd2',0

	dd	fs_HasCd3

	db	'cd3',0

;**********************************************

	dd	0

fs_additional_handlers:

        dd      biosdisk_handler, biosdisk_enum_root

; add new handlers here

        dd      0

endg

file_system_lfn:

; in: eax->fileinfo block

; operation codes:

; 0 : read file

; 1 : read folder

; 2 : create/rewrite file

; 3 : write/append to file

; 4 : set end of file

; 5 : get file/directory attributes structure

; 6 : set file/directory attributes structure

; 7 : start application

; 8 : delete file

; 9 : create directory

    cmp dword [eax], 7

    je .do_exec

; parse file name

	xchg	ebx, eax

	lea	esi, [ebx+20]

	lodsb

	test	al, al

	jnz	@f

	mov	esi, [esi]

	lodsb

@@:

	cmp	al, '/'

	jz	.notcurdir

	dec	esi

	mov	ebp, esi

	test	al, al

	jnz	@f

	xor	ebp, ebp

@@:

	mov	esi, [current_slot]

	mov	esi, [esi+APPDATA.cur_dir]

	jmp	.parse_normal

.notcurdir:

	cmp	byte [esi], 0

	jz	.rootdir

	call	process_replace_file_name

.parse_normal:

	mov	edi, rootdirs-8

	xor	ecx, ecx

	push	esi

.scan1:

	pop	esi

	add	edi, ecx

	scasd

	scasd

	mov	cl, byte [edi]

	test	cl, cl

	jz	.notfound_try

	inc	edi

	push	esi

@@:

	lodsb

	or	al, 20h

	scasb

	loopz	@b

	jnz	.scan1

	lodsb

	cmp	al, '/'

	jz	.found1

	test	al, al

	jnz	.scan1

	pop	eax

; directory /xxx

.maindir:

	mov	esi, [edi+4]

.maindir_noesi:

	cmp	dword [ebx], 1

	jnz	.access_denied

	xor	eax, eax

	mov	ebp, [ebx+12]

	mov	edx, [ebx+16]

    ;    add     edx, std_application_base_address

	push	dword [ebx+4]	; first block

	mov	ebx, [ebx+8]	; flags

; ebx=flags, [esp]=first block, ebp=number of blocks, edx=return area, esi='Next' handler

	mov	edi, edx

	push    ecx

	mov	ecx, 32/4

	rep	stosd

	pop     ecx

	mov	byte [edx], 1	; version

.maindir_loop:

	call	esi

	jc	.maindir_done

	inc	dword [edx+8]

	dec	dword [esp]

	jns	.maindir_loop

	dec	ebp

	js	.maindir_loop

	inc	dword [edx+4]

	mov	dword [edi], 0x10	; attributes: folder

	mov	dword [edi+4], 1	; name type: UNICODE

	push	eax

	xor	eax, eax

	add	edi, 8

	push    ecx

	mov	ecx, 40/4-2

	rep	stosd

	pop     ecx

	pop	eax

	push	eax edx

; convert number in eax to decimal UNICODE string

	push	edi

	push    ecx

	push	-'0'

	mov	ecx, 10

@@:

	xor	edx, edx

	div	ecx

	push	edx

	test	eax, eax

	jnz	@b

@@:

	pop	eax

	add	al, '0'

	stosb

	test	bl, 1		; UNICODE name?

	jz	.ansi2

	mov	byte [edi], 0

	inc	edi

.ansi2:

	test	al, al

	jnz	@b

	mov	byte [edi-1], 0

	pop     ecx

	pop	edi

; UNICODE name length is 520 bytes, ANSI - 264

	add	edi, 520

	test	bl, 1

	jnz	@f

	sub	edi, 520-264

@@:

	pop	edx eax

	jmp	.maindir_loop

.maindir_done:

	pop	eax

	mov	ebx, [edx+4]

	xor	eax, eax

	dec	ebp

	js	@f

	mov	al, ERROR_END_OF_FILE

@@:

	mov	[image_of_eax], eax

	mov	[image_of_ebx], ebx

	ret

; directory /

.rootdir:

	cmp	dword [ebx], 1	; read folder?

	jz	.readroot

.access_denied:

	mov	dword [image_of_eax], 10      ; access denied

	ret

.readroot:

; virtual root folder - special handler

	mov	esi, virtual_root_query

	mov	ebp, [ebx+12]

	mov	edx, [ebx+16]

    ;    add     edx, std_application_base_address

	push	dword [ebx+4]	; first block

	mov	ebx, [ebx+8]	; flags

	xor	eax, eax

; eax=0, [esp]=first block, ebx=flags, ebp=number of blocks, edx=return area

	mov	edi, edx

	mov	ecx, 32/4

	rep	stosd

	mov	byte [edx], 1	; version

.readroot_loop:

	cmp	dword [esi], eax

	jz	.readroot_done_static

	call	dword [esi]

	add	esi, 4

	test	eax, eax

	jnz	@f

.readroot_next:

	or	ecx, -1

	xchg	esi, edi

	repnz	scasb

	xchg	esi, edi

	jmp	.readroot_loop

@@:

	xor	eax, eax

	inc	dword [edx+8]

	dec	dword [esp]

	jns	.readroot_next

	dec	ebp

	js	.readroot_next

	inc	dword [edx+4]

	mov	dword [edi], 0x10	; attributes: folder

	mov	dword [edi+4], ebx	; name type: UNICODE

	add	edi, 8

	mov	ecx, 40/4-2

	rep	stosd

	push	edi

@@:

	lodsb

	stosb

	test	bl, 1

	jz	.ansi

	mov	byte [edi], 0

	inc	edi

.ansi:

	test	eax, eax

	jnz	@b

	pop	edi

	add	edi, 520

	test	bl, 1

	jnz	.readroot_loop

	sub	edi, 520-264

	jmp	.readroot_loop

.readroot_done_static:

        mov     esi, fs_additional_handlers-8

        sub     esp, 16

.readroot_ah_loop:

        add     esi, 8

        cmp     dword [esi], 0

        jz      .readroot_done

        xor     eax, eax

.readroot_ah_loop2:

        push    edi

        lea     edi, [esp+4]

        call    dword [esi+4]

        pop     edi

        test    eax, eax

        jz      .readroot_ah_loop

        inc     dword [edx+8]

        dec     dword [esp+16]

        jns     .readroot_ah_loop2

        dec     ebp

        js      .readroot_ah_loop2

        push    eax

        xor     eax, eax

        inc     dword [edx+4]

        mov     dword [edi], 0x10       ; attributes: folder

        mov     dword [edi+4], ebx

        add     edi, 8

        mov     ecx, 40/4-2

        rep     stosd

        push    esi edi

        lea     esi, [esp+12]

@@:

        lodsb

        stosb

        test    bl, 1

        jz      .ansi3

        mov     byte [edi], 0

        inc     edi

.ansi3:

        test    al, al

        jnz     @b

        pop     edi esi eax

        add     edi, 520

        test    bl, 1

        jnz     .readroot_ah_loop2

        sub     edi, 520-264

        jmp     .readroot_ah_loop2

.readroot_done:

        add     esp, 16

	pop	eax

	mov	ebx, [edx+4]

	xor	eax, eax

	dec	ebp

	js	@f

	mov	al, ERROR_END_OF_FILE

@@:

	mov	[image_of_eax], eax

	mov	[image_of_ebx], ebx

	ret

.notfound_try:

        mov     edi, fs_additional_handlers

@@:

        cmp     dword [edi], 0

        jz      @f

        call    dword [edi]

        scasd

        scasd

        jmp     @b

.notfound:

	mov	dword [image_of_eax], ERROR_FILE_NOT_FOUND

	and	dword [image_of_ebx], 0

	ret

.notfounda:

        cmp     edi, esp

        jnz     .notfound

        add     esp, 8

        jmp     .notfound

.found1:

	pop	eax

	cmp	byte [esi], 0

	jz	.maindir

.found2:

; read partition number

	xor	ecx, ecx

	xor	eax, eax

@@:

	lodsb

	cmp	al, '/'

	jz	.done1

	test	al, al

	jz	.done1

	sub	al, '0'

	cmp	al, 9

	ja	.notfounda

	lea	ecx, [ecx*5]

	lea	ecx, [ecx*2+eax]

	jmp	@b

.done1:

	jecxz	.notfounda

	test	al, al

	jnz	@f

	dec	esi

@@:

	cmp	byte [esi], 0

	jnz	@f

	test	ebp, ebp

	jz	@f

	mov	esi, ebp

	xor	ebp, ebp

@@:

; now [edi] contains handler address, ecx - partition number,

; esi points to ASCIIZ string - rest of name

	jmp	dword [edi]

.do_exec:

          lea ebx, [eax+20]

          cmp byte [ebx],0

          jnz @F

          mov ebx, [ebx+1]

@@:

          push  dword [eax+4]

          push  dword [eax+8]

          push  ebx

          call _sys_exec

          mov [image_of_eax], eax

          add esp, 12

          ret

; handlers for devices

; in: ecx = 0 => query virtual directory /xxx

; in: ecx = partition number

;     esi -> relative (for device) name

;     ebx -> fileinfo

;     ebp = 0 or pointer to rest of name from folder addressed by esi

; out: [image_of_eax]=image of eax, [image_of_ebx]=image of ebx

fs_OnRamdisk:

	cmp	ecx, 1

	jnz	file_system_lfn.notfound

	mov	eax, [ebx]

	cmp	eax, fs_NumRamdiskServices

	jae	.not_impl

	mov	ecx, [ebx+12]

	mov	edx, [ebx+16]

   ;     add     edx, std_application_base_address

	add	ebx, 4

	call	dword [fs_RamdiskServices + eax*4]

	mov	[image_of_eax], eax

	mov	[image_of_ebx], ebx

	ret

.not_impl:

	mov	dword [image_of_eax], 2       ; not implemented

	ret

fs_NotImplemented:

	mov	eax, 2

	ret

fs_RamdiskServices:

	dd	fs_RamdiskRead

	dd	fs_RamdiskReadFolder

	dd	fs_RamdiskRewrite

	dd	fs_RamdiskWrite

	dd	fs_RamdiskSetFileEnd

	dd	fs_RamdiskGetFileInfo

	dd	fs_RamdiskSetFileInfo

	dd	0

	dd	fs_RamdiskDelete

	dd	fs_RamdiskCreateFolder

fs_NumRamdiskServices = ($ - fs_RamdiskServices)/4

fs_OnFloppy:

	cmp	ecx, 2

	ja	file_system_lfn.notfound

	mov	eax, [ebx]

	cmp	eax, fs_NumFloppyServices

	jae	fs_OnRamdisk.not_impl

	call	reserve_flp

	mov	[flp_number], cl

	mov	ecx, [ebx+12]

	mov	edx, [ebx+16]

   ;     add     edx, std_application_base_address

	add	ebx, 4

	call	dword [fs_FloppyServices + eax*4]

	and	[flp_status], 0

	mov	[image_of_eax], eax

	mov	[image_of_ebx], ebx

	ret

fs_FloppyServices:

	dd	fs_FloppyRead

	dd	fs_FloppyReadFolder

	dd	fs_FloppyRewrite

	dd	fs_FloppyWrite

	dd	fs_FloppySetFileEnd

	dd	fs_FloppyGetFileInfo

	dd	fs_FloppySetFileInfo

	dd	0

	dd	fs_FloppyDelete

	dd	fs_FloppyCreateFolder

fs_NumFloppyServices = ($ - fs_FloppyServices)/4

fs_OnHd0:

	call	reserve_hd1

	mov	[hdbase], 0x1F0

	mov	[hdid], 0

	push	1

	jmp	fs_OnHd

fs_OnHd1:

	call	reserve_hd1

	mov	[hdbase], 0x1F0

	mov	[hdid], 0x10

	push	2

	jmp	fs_OnHd

fs_OnHd2:

	call	reserve_hd1

	mov	[hdbase], 0x170

	mov	[hdid], 0

	push	3

	jmp	fs_OnHd

fs_OnHd3:

	call	reserve_hd1

	mov	[hdbase], 0x170

	mov	[hdid], 0x10

	push	4

fs_OnHd:

	call	reserve_hd_channel

	pop	eax

	mov	[hdpos], eax

	cmp	ecx, 0x100

	jae	fs_OnHdAndBd.nf

	cmp	cl, [DRIVE_DATA+1+eax]

fs_OnHdAndBd:

	jbe	@f

.nf:

	call	free_hd_channel

	and	[hd1_status], 0

	mov	dword [image_of_eax], 5       ; not found

	ret

@@:

	mov	[fat32part], ecx

	push	ebx esi

	call	choice_necessity_partition_1

	pop	esi ebx

	mov	ecx, [ebx+12]

	mov	edx, [ebx+16]

    ;    add     edx, std_application_base_address

	mov	eax, [ebx]

	cmp	eax, fs_NumHdServices

	jae	.not_impl

	add	ebx, 4

	call	dword [fs_HdServices + eax*4]

	call	free_hd_channel

	and	[hd1_status], 0

	mov	[image_of_eax], eax

	mov	[image_of_ebx], ebx

	ret

.not_impl:

	call	free_hd_channel

	and	[hd1_status], 0

	mov	dword [image_of_eax], 2       ; not implemented

	ret

fs_HdServices:

	dd	fs_HdRead

	dd	fs_HdReadFolder

	dd	fs_HdRewrite

	dd	fs_HdWrite

	dd	fs_HdSetFileEnd

	dd	fs_HdGetFileInfo

	dd	fs_HdSetFileInfo

	dd	0

	dd	fs_HdDelete

	dd	fs_HdCreateFolder

fs_NumHdServices = ($ - fs_HdServices)/4

;*******************************************************

fs_OnCd0:

	call	reserve_cd

	mov  [ChannelNumber],1

	mov  [DiskNumber],0

	push	6

	push	1

	jmp	fs_OnCd

fs_OnCd1:

	call	reserve_cd

	mov  [ChannelNumber],1

	mov  [DiskNumber],1

	push	4

	push	2

	jmp	fs_OnCd

fs_OnCd2:

	call	reserve_cd

	mov  [ChannelNumber],2

	mov  [DiskNumber],0

	push	2

	push	3

	jmp	fs_OnCd

fs_OnCd3:

	call	reserve_cd

	mov  [ChannelNumber],2

	mov  [DiskNumber],1

	push	0

	push	4

fs_OnCd:

	call	reserve_cd_channel

	pop	eax

	mov	[cdpos], eax

	pop	eax

	cmp	ecx, 0x100

	jae	.nf

	push	ecx ebx

	mov	cl,al

	mov	bl,[DRIVE_DATA+1]

	shr	bl,cl

	test	bl,2

	pop	ebx ecx

	jnz	@f

.nf:

	call	free_cd_channel

	and    [cd_status], 0

	mov	dword [image_of_eax], 5       ; not found

	ret

@@:

	mov	ecx, [ebx+12]

	mov	edx, [ebx+16]

    ;    add     edx, std_application_base_address

	mov	eax, [ebx]

	cmp	eax,fs_NumCdServices

	jae	 .not_impl

	add	ebx, 4

	call	dword [fs_CdServices + eax*4]

	call	free_cd_channel

	and	[cd_status], 0

	mov	[image_of_eax], eax

	mov	[image_of_ebx], ebx

	ret

.not_impl:

	call	free_cd_channel

	and	[cd_status], 0

	mov	dword [image_of_eax], 2       ; not implemented

	ret

fs_CdServices:

	dd	fs_CdRead

	dd	fs_CdReadFolder

	dd	fs_NotImplemented

	dd	fs_NotImplemented

	dd	fs_NotImplemented

	dd	fs_CdGetFileInfo

	dd	fs_NotImplemented

	dd	0

	dd	fs_NotImplemented

	dd	fs_NotImplemented

fs_NumCdServices = ($ - fs_CdServices)/4

;*******************************************************

fs_HasRamdisk:

	mov	al, 1	; we always have ramdisk

	ret

fs_HasFloppy:

	cmp	byte [DRIVE_DATA], 0

	setnz	al

	ret

fs_HasHd0:

	mov	al, [DRIVE_DATA+1]

	and	al, 11000000b

	cmp	al, 01000000b

	setz	al

	ret

fs_HasHd1:

	mov	al, [DRIVE_DATA+1]

	and	al, 00110000b

	cmp	al, 00010000b

	setz	al

	ret

fs_HasHd2:

	mov	al, [DRIVE_DATA+1]

	and	al, 00001100b

	cmp	al, 00000100b

	setz	al

	ret

fs_HasHd3:

	mov	al, [DRIVE_DATA+1]

	and	al, 00000011b

	cmp	al, 00000001b

	setz	al

	ret

;*******************************************************

fs_HasCd0:

	mov	al, [DRIVE_DATA+1]

	and	al, 11000000b

	cmp	al, 10000000b

	setz	al

	ret

fs_HasCd1:

	mov	al, [DRIVE_DATA+1]

	and	al, 00110000b

	cmp	al, 00100000b

	setz	al

	ret

fs_HasCd2:

	mov	al, [DRIVE_DATA+1]

	and	al, 00001100b

	cmp	al, 00001000b

	setz	al

	ret

fs_HasCd3:

	mov	al, [DRIVE_DATA+1]

	and	al, 00000011b

	cmp	al, 00000010b

	setz	al

	ret

;*******************************************************

; fs_NextXXX functions:

; in: eax = partition number, from which start to scan

; out: CF=1 => no more partitions

;      CF=0 => eax=next partition number

fs_NextRamdisk:

; we always have /rd/1

	test	eax, eax

	stc

	jnz	@f

	mov	al, 1

	clc

@@:

	ret

fs_NextFloppy:

; we have /fd/1 iff (([DRIVE_DATA] and 0xF0) != 0) and /fd/2 iff (([DRIVE_DATA] and 0x0F) != 0)

	test	byte [DRIVE_DATA], 0xF0

	jz	.no1

	test	eax, eax

	jnz	.no1

	inc	eax

	ret	; CF cleared

.no1:

	test	byte [DRIVE_DATA], 0x0F

	jz	.no2

	cmp	al, 2

	jae	.no2

	mov	al, 2

	clc

	ret

.no2:

	stc

	ret

; on hdx, we have partitions from 1 to [0x40002+x]

fs_NextHd0:

	push	0

	jmp	fs_NextHd

fs_NextHd1:

	push	1

	jmp	fs_NextHd

fs_NextHd2:

	push	2

	jmp	fs_NextHd

fs_NextHd3:

	push	3

fs_NextHd:

	pop	ecx

	movzx	ecx, byte [DRIVE_DATA+2+ecx]

	cmp	eax, ecx

	jae	fs_NextFloppy.no2

	inc	eax

	clc

	ret

;*******************************************************

fs_NextCd:

; we always have /cdX/1

	test	eax, eax

	stc

	jnz	@f

	mov	al, 1

	clc

@@:

	ret

;*******************************************************

; Additional FS handlers.

; This handler gets the control each time when fn 70 is called

; with unknown item of root subdirectory.

; in: esi -> name

;     ebp = 0 or rest of name relative to esi

; out: if the handler processes path, he must not return in file_system_lfn,

;      but instead pop return address and return directly to the caller

;      otherwise simply return

; here we test for /bd/... - BIOS disks

biosdisk_handler:

        cmp     [NumBiosDisks], 0

        jz      .ret

        mov     al, [esi]

        or      al, 20h

        cmp     al, 'b'

        jnz     .ret

        mov     al, [esi+1]

        or      al, 20h

        cmp     al, 'd'

        jnz     .ret

        push    esi

        inc     esi

        inc     esi

        cmp     byte [esi], '0'

        jb      .ret2

        cmp     byte [esi], '9'

        ja      .ret2

        xor     edx, edx

@@:

        lodsb

        test    al, al

        jz      .ok

        cmp     al, '/'

        jz      .ok

        sub     al, '0'

        cmp     al, 9

        ja      .ret2

        lea     edx, [edx*5]

        lea     edx, [edx*2+eax]

        jmp     @b

.ret2:

        pop     esi

.ret:

        ret

.ok:

        cmp     al, '/'

        jz      @f

        dec     esi

@@:

        add     dl, 80h

        xor     ecx, ecx

@@:

        cmp     dl, [BiosDisksData+ecx*4]

        jz      .ok2

        inc     ecx

        cmp     ecx, [NumBiosDisks]

        jb      @b

        jmp     .ret2

.ok2:

        add     esp, 8

        test    al, al

        jnz     @f

        mov     esi, fs_BdNext

        jmp     file_system_lfn.maindir_noesi

@@:

        push    ecx

        push    fs_OnBd

        mov     edi, esp

        jmp     file_system_lfn.found2

fs_BdNext:

        cmp     eax, [BiosDiskPartitions+ecx*4]

	inc	eax

	cmc

	ret

fs_OnBd:

        pop     edx edx

; edx = disk number, ecx = partition number

; esi+ebp = name

	call	reserve_hd1

	add     edx, 0x80

	mov     [hdpos], edx

	cmp     ecx, [BiosDiskPartitions+(edx-0x80)*4]

	jmp     fs_OnHdAndBd

; This handler is called when virtual root is enumerated

; and must return all items which can be handled by this.

; It is called several times, first time with eax=0

; in: eax = 0 for first call, previously returned value for subsequent calls

; out: eax = 0 => no more items

;      eax != 0 => buffer pointed to by edi contains name of item

; here we enumerate existing BIOS disks /bd

biosdisk_enum_root:

        cmp     eax, [NumBiosDisks]

        jae     .end

        push    eax

        movzx   eax, byte [BiosDisksData+eax*4]

        sub     al, 80h

        push    eax

        mov     al, 'b'

        stosb

        mov     al, 'd'

        stosb

        pop     eax

        cmp     al, 10

        jae     .big

        add     al, '0'

        stosb

        mov     byte [edi], 0

        pop     eax

        inc     eax

        ret

.end:

        xor     eax, eax

        ret

.big:

        push    ecx

        push    -'0'

        mov     ecx, 10

@@:

        xor     edx, edx

        div     ecx

        push    edx

        test    eax, eax

        jnz     @b

        xchg    eax, edx

@@:

        pop     eax

        add     al, '0'

        stosb

        jnz     @b

        pop     ecx

        pop     eax

        inc     eax

        ret

process_replace_file_name:

	mov	ebp, [full_file_name_table]

	mov	edi, [full_file_name_table.size]

	dec	edi

	shl	edi, 7

	add	edi, ebp

.loop:

	cmp	edi, ebp

	jb	.notfound

	push	esi edi

@@:

	cmp	byte [edi], 0

	jz	.dest_done

	lodsb

	test	al, al

	jz	.cont

	or	al, 20h

	scasb

	jz	@b

	jmp	.cont

.dest_done:

	cmp	byte [esi], 0

	jz	.found

	cmp	byte [esi], '/'

	jnz	.cont

	inc	esi

	jmp	.found

.cont:

	pop	edi esi

	sub	edi, 128

	jmp	.loop

.found:

	pop	edi eax

	mov	ebp, esi

	cmp	byte [esi], 0

	lea	esi, [edi+64]

	jnz	.ret

.notfound:

	xor	ebp, ebp

.ret:

	ret

sys_current_directory:

	mov	esi, [current_slot]

	mov	esi, [esi+APPDATA.cur_dir]

	mov	edx, esi

	dec	eax

	jz	.set

	dec	eax

	jz	.get

	ret

.get:

; sysfunction 30.2: [for app] eax=30,ebx=2,ecx->buffer,edx=len

; for our code: ebx->buffer,ecx=len

@@:

	lodsb

	test	al, al

	jnz	@b

	sub	esi, edx

	inc	esi

	mov	[esp+36], esi

	cmp	ecx, esi

	jbe	@f

	mov	ecx, esi

@@:

	cmp	ecx, 1

	jbe	.ret

	mov	esi, edx

	mov	edi, ebx

	mov	al, '/'

	stosb

	dec	ecx

	dec	ecx

	rep	movsb

	mov	byte [edi], 0

.ret:

	ret

.set:

; sysfunction 30.1: [for app] eax=30,ebx=1,ecx->string

; for our code: ebx->string to set

@@:

	inc	esi

	cmp	byte [esi-1], 0

	jnz	@b

	dec	esi

	cmp	byte [ebx], '/'

	jz	.set_absolute

; string gives relative path

.relative:

	cmp	byte [ebx], 0

	jz	.set_ok

	cmp	word [ebx], '.'

	jz	.set_ok

	cmp	word [ebx], './'

	jnz	@f

	add	ebx, 2

	jmp	.relative

@@:

	cmp	word [ebx], '..'

	jnz	.doset_relative

	cmp	byte [ebx+2], 0

	jz	@f

	cmp	byte [ebx+2], '/'

	jnz	.doset_relative

@@:

	dec	esi

	cmp	byte [esi], '/'

	jnz	@b

	mov	byte [esi], 0

	add	ebx, 3

	jmp	.relative

.doset_relative:

	add	edx, 0x1000

	mov	byte [esi], '/'

	inc	esi

	cmp	esi, edx

	jae	.overflow_esi

@@:

	mov	al, [ebx]

	inc	ebx

	mov	[esi], al

	inc	esi

	test	al, al

	jz	.set_ok

	cmp	esi, edx

	jb	@b

.overflow_esi:

	mov	byte [esi-1], 0 	; force null-terminated string

.set_ok:

	ret

.set_absolute:

	lea	esi, [ebx+1]

	call	process_replace_file_name

	mov	edi, edx

	add	edx, 0x1000

.set_copy:

	lodsb

	stosb

	test	al, al

	jz	.set_part2

.set_copy_cont:

	cmp	edi, edx

	jb	.set_copy

.overflow_edi:

	mov	byte [edi-1], 0

	ret