.model small
.stack 100

.data
MSG DB "Hello World !", 0dh, 0ah, "$"

DISPLAY MACRO STRING
    PUSH AX
    PUSH DX

    MOV DX, OFFSET STRING
    MOV AH, 09H
    INT 21H

    POP DX
    POP AX
ENDM

.code
mov ax, @data
mov ds, ax

MOV DL, 'O'
CALL DISP
MOV DL, 'K'
CALL DISP

mov ah, 4ch
int 21h

DISP PROC NEAR
    PUSH AX

    MOV AH, 2
    INT 21H

    POP AX
    RET
DISP ENDP

End