title: How to save user-input integer to a register
body: <p>I am unsure of how to actually store user-input data to a register. I would like to prompt the user for a signed base-10 integer, then store that integer to the <code>bx</code> register. What I have does not seem to be actually storing any data from what I can tell: </p>
  
  <pre><code>;get user input
  
     mov   ah, 0Ah
     int   21h
  
  
  while:
      mov   bx, ax        ;save char to bx
      cmp   ax, 13        ;is char = carriage return?
      jmp   endwhile      ;if so, we're done
      int   21h           ;get another char
      loop  while
  endwhile:
      ret                 ;end loop
  
  ;print data stored in bx to console
  
      mov   ah, 09
      mov   dx, [bx]
      int   21h
  </code></pre>
  
  <p>Anything in particular sticking out that I'm doing wrong?</p>