;this program converts a hex number in dx to ASCII codes
.model small
.stack 100h
.data

num = 0e39fh

.code
        mov ax,@data
        mov ds,ax
        mov ax,0b800h
        mov es,ax
        
        mov ax,3
        int 10h
        
        mov bx,0
        
        mov di,num
        shr di,12           ;leave only the last 4 bits
        call convert
        
        mov di,num
        shr di,8            ;leave only the last 8 bits
        call convert
        
        mov di,num
        shr di,4            ;leave only the last 12 bits
        call convert
        
        mov di,num          ;do not change the number        
        call convert
        
mov ah,4ch
   int 21h
;***********************
convert:
        AND di,0fh          ;make di 0 in all places except last 4 bits
        mov ax,di
        cmp ax,10           ;check # vs char
        jb digit
        add ax,7            ;if character: add 55
digit:  add ax,48           ;if #: add 48
        mov es:[bx],al      ;print to screen
        add bx,2            ;advance bx to next block
    ret 
end