Do programming exercise 10, except that if the user fails to enter a hex-digit character In three tries, display a message and terminate the program

#. Do programming exercise 10, except that if the user fails to enter a hex-digit character In three tries, display a message and terminate the program

Solution:

.model small
.stack 100h
.data
msg1 db 10,13,'ENTER A HEX DIGIT:$'
msg2 db 10,13,'IN DECIMAL IS IT:$'
msg3 db 10,13,'DO YOU WANT TO DO IT AGAIN? y/n$'
msg4 db 10,13,'ILLEGAL CHARACTER- ENTER 0-9 OR A-F:$' 
msg5 db 10,13,'Try Some time later...!$'

.code

  

   again: 
  
    mov cx,0   
    mov ax,@data   
    mov ds,ax   
    lea dx,msg1   
    mov ah,9
   
   
    int 21h       
    mov ah,1   
    int 21h       
    mov bl,al        
    jmp go
   
   
    go:
               
    cmp bl,'9'   
    ja hex   
    jb num   
    je num
   
   
    hex:
          
    cmp bl,'F'    
    ja illegal
   
   
   lea dx,msg2   
   mov ah,9   
   int 21h
  
  
   mov dl,49d    
   mov ah,2    
   int 21h
  
  
  sub bl,17d    
  mov dl,bl    
  mov ah,2    
  int 21h         
  jmp inp
 
 
   inp:
  
   lea dx,msg3    
   mov ah,9    
   int 21h         
   mov ah,1    
   int 21h         
   mov cl,al    
   cmp cl,'y'    
   je again    
   cmp cl,'Y'    
   je again    
   jmp exit
  
  
  num:       
  cmp bl,'0'   
  jb illegal       
  lea dx,msg2    
  mov ah,9   
  int 21h             
  mov dl,bl   
  mov ah,2   
  int 21h       
  jmp inp
 
 
  illegal:
                    
  inc cx       
  cmp cx,3       
  je i2               
  lea dx,msg4       
  mov ah,9       
  int 21h               
  mov ah,1
 
  int 21h               
  mov bl,al                
  jmp go
 
 
  i2:      
  lea dx,msg5      
  mov ah,9      
  int 21h      
  jmp exit    
 
  exit:
 
  mov ah,4ch
  int 21h     

Output: