recursiveProcedure assembly

; multi-segment executable file template.

data segment
    ; add your data here!
    N db ?
    suma db 0
    first db 1
    returnInst dw ?
ends

stack segment
    dw   128  dup(0)
ends

code segment
sum proc
    cmp first, 1d
    je firstTime

    cmp cl, 01d
    je end

    mov al, cl
    mov ah, 0d
    mov dl, 3d
    div dl

    cmp ah, 0d
    jne calling

    add bl, cl

    calling:
        dec cx
        call sum
    end:
        push bx
        push returnInst
        ret

    firstTime:
        pop returnInst
        pop cx
        mov al, 0d
        mov first, 0d
        call sum
sum endp
start:
; set segment registers:
    mov ax, data
    mov ds, ax
    mov es, ax

    mov ah, 01h
    int 21h
    sub al, 48d
    mov ah, 0d
    mov dl, 10d
    mul dl
    mov N, al

    mov ah, 01h
    int 21h
    sub al, 48d
    add N, al

    mov cl, N
    mov ch, 0d
    push cx

    call sum

    pop ax
    mov sum, al

    mov ax, 4c00h ; exit to operating system.
    int 21h
ends

end start ; set entry point and stop the assembler.