org 100h

%macro dodawanie 0
    pop ax
    pop bx
    add ax, bx
    push ax
%endmacro
%macro odejmowanie 0
    pop ax
    pop bx
    sub ax, bx
    push ax
%endmacro
%macro mnozenie 0
    pop ax
    pop bx
    mul bx
    push ax
%endmacro
%macro dzielenie 0
    pop bx
    pop ax
    mov dx, 0
    div bx
    push ax
%endmacro

push word [x]
push word [y]
push word 20
dodawanie
dodawanie
push word 3
dzielenie
pop word [z]

mov ax, 4c00h
int 21h

x: dw 20
y: dw 20
z: dw 0