assume cs:code
data segment
    db ‘welcome to masm!‘
    db 2,24h,71h
data ends

stack segment
    db 16 dup(0)
stack ends
code segment
    start:mov ax,stack
    mov ss,ax
    mov sp,0

    mov ax,data
    mov ds,ax

    mov cx,3
    mov ax,0B800H
    mov es,ax
    mov si,10h
    mov ax,0
    s:
    mov ah,ds:[si]
    push cx
    push si
    mov cx,16
    mov si,0
    add si,160*10+80
    mov bx,0
    mov di,1
    add di,160*10+80

    s1:
    mov al,[bx]
    mov es:[bx+si],al
    mov es:[bx+di],ah
    inc bx
    inc si
    inc di
    loop s1

    pop si
    inc si
    pop cx
    mov dx,es
    add dx,0ah
    mov es,dx

    loop s

    s2:
    jmp short s2

    mov ax,4c00h
    int 21h
code ends
end start