even or odd using dos bios

//dos bios even or odd
data segment
string db 0dh,0ah,'Enter a Number Between 0-9 Or Press Q or q To Exit','$',0dh,0ah
msge db 0dh,0ah,'You Have Entered An Even Number','$',0dh,0ah
msgo db 0dh,0ah,'You Have Entered An Odd Number','$',0dh,0ah
data ends

code segment
assume cs:code,ds:data
start: mov ax,data
       mov ds,ax

 disp: lea dx,string
       mov ah,09h
       int 21h

       cmp ah,01h
       int 21h

       cmp al,'q'
       jz exit

       cmp al,'Q'
       jz exit

       cmp al,30h
       jb disp

       cmp al,39h
       ja disp

       sub al,30h
       RCR al,01h
       jc odd
       lea dx,msge
       jmp skip

  odd: lea dx,msgo

 skip: mov ah,09h
       int 21h
       jmp disp

 exit: mov ah,4ch
       int 21h
code ends
end start