Add Two numbers from keyboard in 8086

add_two_numbers_from_keyboard.asm

.model small
.stack 100h
.data
    first db 10,13, "Enter first character : $"
    second db 10,13, "Enter second character : $"
    output db 10,13, "The output is  : $"
    
.code
    main proc
        
        mov ax, @data
        mov ds, ax
        
        ; macro for displaying message
        disp macro msg
            lea dx, msg
            mov ah, 09h
            int 21h
        endm
        
        ; macro for reading character from keyboard
        read macro 
            mov ah, 01h
            int 21h
        endm
        
        ; printing character
        print macro
            mov ah, 02h
            int 21h
        endm
       
        ; first a message is displayed
        disp first
        ; reading first character
        read
        ; moving the input character to bl register
        mov bl, al
        ; displaying the second message
        disp second
        ; reading second character
        read
        ; adding the content of al to bl
        add bl, al
        ; the number is in ascii form, so converting into decimal.
        sub bl, 30h
        ; displaying the output message
        disp output
        
        mov dl, bl
        print         
        
    main endp
end main