Assembly language program to find sum of first N natural numbers

Add.asm

store macro res
            div x
            mov res,dl;dividing and storing the last bit in dl i.e. is the remainder
            mov dx,0
endm

ansprint macro res
            mov dl,res
            add dl,30h
            mov ah,02h
            int 21h
endm
data segment

    number dw  ? 
            result dw  ? 
    msg db 10,13,"enter a last number to find sum $"
    msgres db 10,13,"sum = $"
           
            res db 8 dup(0)
            x dw 10

data ends 

code segment   
assume cs:code,ds:data
start: 

            mov ax,data
            mov ds,ax
           
    ;displaying the message
            mov dx,offset msg
            mov ah,09h
            int 21h
           
            ;taking the input
            mov ah,01h
            int 21h
            sub al,30h
            mov bh,al
            mov ah,01h
            int 21h
            sub al,30h
            mov bl,al
            mov ax,bx
            aad
            mov bx,ax
                            
                             
                            
            ;storing the number
            mov number,ax
            mov bx,0001h
            mov ax,0000h
            mov cx,number
            label1:
                        add ax,bx
                        inc bl
            loop label1      
                         
    mov result,ax
   
    ;displaying the result message
            mov dx,offset msgres
            mov ah,09h
            int 21h 
                                     
            mov dx,0000h  
            mov ax,result
            ;storing the result
            store res+3
            store res+2
            store res+1
            store res+0
           
            ;displaying the 1st part of result
            ansprint res+0
            ansprint res+1
            ansprint res+2
            ansprint res+3
           
           
           
    ;terminate the program
            mov ax,4c00h
            int 21h                         
                                                                                   
   
code ends
end start