add 4 numbers failed.asm

    ;add 4 numbers failed 
    
    .model small
    .stack 100h
    .data 
    
    a db ?
    b db ?
    
    .code   
    main proc 
    
    mov ax,@data 
    mov ds,ax
    
    mov ah,1
    int 21h
    
    mov bl,al
    mov ah,1
    int 21h
    
    mov bh,al
    mov ah,1
    int 21h
    
    mov ch,al
    mov ah,1
    int 21h
    
    mov ch,al
    add bl,bh
    sub bl,48
    
    mov a,bl 
    mov a,cl
    
    sub a,48
    mov bl,a 
    
    add bl,ch
    sub bl,48
    mov b,bl
    mov ah,2
    mov dl,b
    int 21h
    
    exit:
    mov ah,4ch
    int 21h
    
    main endp
    end main