improved_switc.asm

.model small
.stack 100h  

.data
  a db ?   
  c dw 'you are in level $'
  d dw 'restrictin ...you are in server room $'   
  e dw 'Invalid level entered $'
.code  

main proc 
     
     mov ax, @data
     mov ds, ax 
     
  input:
     mov ah, 1
     int 21h  
     ;caution without al register variable cannot hold value
     mov a, al  
      
     mov ah, 2 
     mov dl, ' '
     int 21h 
        
      cmp a, '0'
     je levelexit
     cmp a, '1'
     je levelexit 
      cmp a, '2'
     je levelexit
      cmp a, '3'
     je levelexit
      cmp a, '4'
     je levelexit
      cmp a, '5'
     je levelexit
      cmp a, '6'
     je warning 
     
     
    ; jge Invalid    
    jg invalid
       
         
     
 Invalid:
        ;LOAD EFFECTIVE ADDRESS
    mov ah, 9
    lea dx, e     
    int 21h 
    
    jmp exit
    
     
 warning:  
       ;LOAD EFFECTIVE ADDRESS
    mov ah, 9
    lea dx, d     
    int 21h      
    
    jmp exit   
    
         
  levelexit:
        ;LOAD EFFECTIVE ADDRESS
    mov ah, 9
    lea dx, c     
    int 21h 
 
    mov ah, 2  
    mov dl, ' '
    int 21h  
    
    mov ah, 2  
    mov dl, a
    int 21h 
        
     exit:    
     ; successful termination
     mov ah, 4ch        
     int 21h  
        
    main endp
end main