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From: almas on 29 Mar 2008 18:18
Hi every body.
I have a text.... many lines, end of line is OD OA
I want to change the beginig of each line
the first 5 bytes remplaced by "�"

Below my code... sorry it is not OK
Who have an idea ?

I use DOS Operating System compiler is A86

mov si,0080h
lodsb
cbw ;extend AL to AX
xchg bx,ax ;swap size to bx for indexing
mov byte [bx+si],0 ;null terminate command line
mov di,inbuff ;our buffer
; dospc: cmp byte [si],32 ;any leading spaces ? ; jne nospc ;nooo
inc si ;yeahh, dump it ; jmp dospc ;check next
nospc: mov cx,1 ;we're here, so we got one arg
copy1: lodsb ;load byte SI to AL
cmp al,0 ;0 ?(end of line)
je done ;yeahh
stosb ;noo, move AL to DI, incrase DI
jmp short copy1 ;go on
done: mov byte [di],0 ;null terminate END of PARSE
gotfile:
mov ax,3d12h ; open file READ/WRITE/NO SHARE
mov dx,offset inbuff ;filename
int 21h

fopok: xchg ax,bx
; ; handle ; mov word [bytes],256 ; buffer size
; ; NOTE BX will not change I put value 0 into count 1 and 2
; ; xor ax,ax ; mov offset count1,ax ; clear out ; mov offset count2,ax

readlop: mov ah,3fh ; read file ; mov bx,[filehandle]
mov cx,[bytes] ;read buffer full
mov dx,offset address ;buffer
int 21h
cmp ax,0 ;nothing read ? (end of file)
ja main ;nooo, do the work
jmp short quit ;yeahh, we're done
main:
mov [bytes],ax ;bytes read
mov cx,ax ;counter
mov si,address ;file buffer
; ---------- here the "engine" --------------
push cx
mov cx,5 ; i want to remplace 5 bytes by �
push bx ; save the handle
xor bx,bx ; will be used like counter

mloop:
lodsw
inc bx ; count
inc bx
cmp ax,0D0Ah ; is it end of line ?
jz mloop
lodsb
inc bx
cmp al,0Dh
jz mon0a
mov byte si,0A8h ; new line, then remplace by �
lodsb
inc bx
mon0a:
cmp al,0Ah
jz mloop
mov byte si, 0A8h ; again change with �
loop mloop
pop cx
sub cx,bx ; resize file buffer
pop bx ; restore handle

; ----------- end of my "engine " -----------

mov ax,4200h ; seek set file position beginning
mov cx,[count1] ;most significant part of offset
mov dx,[offset count2] ;least significant part of offset
int 21h

mov cx,[bytes] ;get offset size
mov dx,[offset count1] ;the most significant part
mov ax,[count2] ;the least significant part
add ax,cx ;add offset to least sig part
adc dx,0 ;add with carry
mov [offset count1],dx ;save them back for next loop
mov [count2],ax

mov ah,40h ; write to file mov bx,[filehandle]
mov dx,offset address ;buffer
int 21h
cmp word [bytes],256 ;less than 256 bytes left ?
jb quit ;yeahh, must be last read
jmp short readlop ;noo, go on reading
quit: ; cmp word [filehandle],0 ;any filehandle

mov ah,3eh ; close file
int 21h
nofile: ret ; int 20h

; DATA
bytes dw ,100h ; size buffer for file
filesize: db: 0,0
filehandle dw 0,0
count1 dw 0,0 ; at the begining, value must be 0
count2 dw 0,0
inbuff: db: 0,0
address: db: ,0,0


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