name echo         

; .model small

ZAS      SEGMENT   STACK
         DW        64 DUP(?)
ZAS      ENDS

DATA     SEGMENT
ENTR     DW        13
DATA     ENDS


CODE     SEGMENT
         ASSUME    CS:CODE, SS:ZAS, DS:DATA
start:   MOV AX, SEG DATA
         MOV DS, AX
         mov ah,7
         int 21h
         MOV DL, OFFSET ENTR
         cmp al,DX
         jz koniec
         mov dl, al
         mov ah, 2
         int 21h
         jmp start
koniec:  mov ah, 4ch
         int 21h
CODE     ENDS
         end start