old/ASM/!ALL/swap.asm

.model small
.code 
org 100h
start:
	mov ah,	3ch
	mov cx,	0
	mov dx,	offset fname2
	int 21h

	mov di, offset handle2
	mov [di], ax

	mov ax,	3d00h
	mov dx,	offset fname
	int 21h

	mov di, offset handle
	mov [di], ax

	mov ah,	3fh
	mov bx, [di]
	mov cx,	500
	mov dx, offset string
	int 21h
	
	mov cx,	ax
	mov si,	cx
	mov word ptr string[si], 0A0Dh
	mov di,	2
	sub cx, 2
reading:
	mov si,	cx
	cmp word ptr string[si], 0A0Dh
	je lineend
	jmp normal
lineend:
	mov ah,	40h
	mov si, offset handle2
	mov bx, [si]
	mov si,	cx
	PUSH cx
	mov cx,	di
	mov dx,	offset string
	add dx,	si
	add dx,	2
	int 21h
	POP cx
	mov di, 0
normal:
	inc di
	loop reading
;------------------------------
	mov ah,	40h
	mov si, offset handle2
	mov bx, [si]
	mov si,	cx
	mov cx,	di
	add cx,	2
	mov dx,	offset string
	add dx,	si
	int 21h
	mov ah,	3eh
	mov di, offset handle
	mov bx,	[di]
	int 21h

	mov ah,	3eh
	mov di, offset handle2
	mov bx,	[di]
	int 21h

	int 20h

fname	db 'inp.txt',0
fname2	db 'out.txt',0
handle	dw ?
handle2 dw ?
cool	dw 0A0Dh
string	db 501 dup (?)
end start