String printing in assembly 8086

string.asm

.model small
.stack 100h
.data
    a db ?
    b db ?
    txt1 dw 'Enter 1st input: $'
    txt2 dw 'Enter 2nd input: $'
    txt3 dw 'a: $'
    txt4 dw 'b: $'
    txt5 dw 'sum: $'

.code
    main proc
        mov ax,@data        ;Load data?
        mov ds,ax
        
        
        lea dx,txt1         ;output first string        
        mov ah,9
        int 21h    
        
        mov ah,1
        int 21h             ;input a
        mov a,al
        
        mov ah,2
        mov dl,0ah 
        int 21h   
        mov dl,0dh          ;output newline and caret ret
        int 21h  
        
        mov ah,9
        lea dx,txt2         ;output second string
        int 21h 
        
        mov ah,1
        int 21h
        mov b,al            ;input b
        
        mov ah,2
        mov dl,0ah 
        int 21h   
        mov dl,0dh          ;output newline and caret ret
        int 21h
        
        mov ah,9
        lea dx,txt3         ;output 3rd string
        int 21h
        
        mov ah,2
        mov dl,a            ;output value of a
        int 21h
        
        mov ah,2
        mov dl,0ah 
        int 21h   
        mov dl,0dh          ;output newline and caret ret
        int 21h
        
        mov ah,9
        lea dx,txt4         ;output 4th string
        int 21h 
        
        mov ah,2
        mov dl,b            ;output value of b
        int 21h
        
        mov ah,2
        mov dl,0ah 
        int 21h   
        mov dl,0dh          ;output newline and caret ret
        int 21h
        
        mov bl,a
        mov bh,b 
        add bl,bh
        sub bl,30h
        mov a,bl
        
        mov ah,9
        lea dx,txt5         ;output 5th string
        int 21h 
        
        mov ah,2
        mov dl,a            ;output value of a
        int 21h
        
        
                        
        main endp
    end main