title: Hex to Ascii Conversion in x86 alp
body: <p>I am currently learning alp(x86).I recently stumbled upon a program which is used to display characters stored in array which are ,basically in hex form.in order to display them we should convert them into ascii and then display them.</p>
  
  <pre><code>    ;display procedure for 64bit
       display:
      mov rsi,char_answer+15
      mov rcx,16
      cnt:    mov rdx,0
              mov rbx,16h
              div rbx
              cmp dl,09h
              jbe add30
              add dl,07h
      add30:    add dl,30h
              mov [rsi],dl
              dec rsi
              dec rcx
              jnz cnt
      scall 1,1,char_answer,16
      ret
  </code></pre>
  
  <p>so in above code i could not get why we are comparing with 09h and then adding 30h or 07h.</p>
  
  <p>Thankyou.</p>