Поиск заданной символьной цепочки на произвольном магнитном диске.

;TASM, COM - файл
.model tiny
.code
.386
ORG 100h
START:
;
    mov ah,0Ah
    lea dx,Strin
    int 21h
 
    mov ah,9
    lea dx,LF
    int 21h
 
    mov ah,2Fh
    int 21h
    mov [DTA],bx
 
    mov ah,4Eh
    lea dx,Maska
    mov cx,0FFh
    int 21h
 
CmpNoFile   macro
    mov si,[DTA]
    test byte ptr [si+15h],00001000b
    jnz short ok_metka
    test byte ptr [si+15h],00010000b
    jnz short ok_metka
    endm
 
    CmpNoFile
 
    call File
ok_metka:
    mov ah,4Fh
    int 21h
    jc short exit
 
    CmpNoFile
 
    call File
    jmp short ok_metka
;-----------------------------------
exit:
    ret
;--------------------------------
File    proc    near
    mov dx,[DTA]
    add dx,1Eh
    mov ax,3D00h
    int 21h
    mov [ID_read],ax
 
    lea si,Strin        
    inc si
    inc byte ptr [si]
    inc si
file3:
    call Read
    cmp ax,0
    jz short file2
    mov [Ind],ax
    lodsb
    dec si
    lea di,buf
    mov bx,di
file1:
    mov cx,[Ind]
 
    repne scasb
    dec di
    test cx,cx
    jz short fileExit
 
    xor cx,cx
    mov cl,[si-1]
push si
    repe cmpsb
    dec di
pop si
    test cx,cx
    jnz short no_file
    call Vivod
no_file:
push di
    sub di,bx
    sub [Ind],di
pop di
    mov bx,di
    jmp short file1
fileExit:
    call Lseek
    jmp short file3
file2:
    call Close
    mov dword ptr [Seek],0
    mov word ptr [Ind],0
    dec byte ptr [si-1]
    ret
;--------------------
Vivod   proc    near
push di
push ax
push cx
    mov di,[DTA]
    add di,1Eh
    mov dx,di
    xor al,al
    mov cx,13
    repne scasb
    dec di
    mov byte ptr [di],'$'
    mov ah,9
    int 21h
    lea dx,LF
    int 21h
pop cx
pop ax
pop di
    ret
Vivod   endp
;-------------------------
Close   proc    near
    mov bx,[ID_read]
    mov ah,3Eh
    int 21h
    ret
Close   endp
;-----------------------
Lseek   proc    near
    mov bx,[ID_read]
    lea dx,buf
    sub di,dx
    mov dx,di
    inc dx
    add [Seek],edx
    mov cx,word ptr [Seek+2]
    mov ax,4200h
    int 21h
    ret
Lseek   endp
;---------------------
Read    proc    near
    lea dx,Buf
    mov ah,3Fh
    mov bx,[ID_read]
    mov cx,0FB00h
    int 21h
    ret
Read    endp
;--------------------------------
LF      db  10,13,'$'
Seek        dd  0
ID_read     dw  0
Ind     dw  0
;---------------------------------
File    endp
;--------------------------------
Maska   db  '*.*',0
DTA dw  ?
Strin   db  254,255 dup ('$')
Buf:
 
    end start