How to declare counter in assembly language / emu8086?

Question

I am new in assembly language. I just need some advice or tips on how can I declare counter loop that decrement the input number. For example, input = 5, print = 55555.5555.555.55.5

include emu8086.inc
org 100h

print 'Input a number: '

MOV AH,01H ;input
INT 21H
MOV BL,AL

MOV DL,BL

SUB BL,30H
MOV CL,BL

printn

print 'Output: '
DISP:
MOV AH,02H
INT 21H

DEC CL
JNZ DISP

MOV AH,4CH
INT 21H

Input: 5
Output: 55555

This is very basic for you guys, and for me it is very hard to learn but I won't stop learning. I just need some advice for this one.

Answer 1

The solution can be so

include emu8086.inc
org 100h

print 'Input a number: '

MOV AH,01H ;input digit to output 
INT 21H
MOV DL,AL

MOV AH,01H ;input number of times to output 
INT 21H
MOV CL,AL
SUB CL,30H

printn

print 'Output: '
DISP:
MOV AH,02H
INT 21H

DEC CL
JNZ DISP

MOV AH,4CH
INT 21H

This solves the problem of different inputs, but there is no checking if input is valid.