KONST_S	equ 254
KONST_P	equ 360
KONST_G	equ 24

org 256

	mov ah,4ah
	mov bx,2*4096
	int 21h
	jc exit

	cld
	mov si,80h
	lodsb
	cbw
	add si,ax
	xor ax,ax
	int 33h
	inc ax
	jnz exit
	mov [si],ax

	mov ah,3dh
	mov dx,82h
	int 21h
	jc exit

	xchg ax,bx
	mov cx,321*201
	mov dx,area
	mov ah,3fh
	int 21h
	sub cx,ax
	jnz exit

	mov ah,0fh
	int 10h
	cbw
	push ax
	mov al,13h
	int 10h
	
	mov al,7
	mov dx,319
	int 33h
	inc ax
	mov dx,199
	int 33h

	mov ax,1200h
	xor bx,bx
	cwd
	mov di,1010h
	mov si,180
	mov bp,-82
next	push cx
	mov cl,ah
	xchg ax,di
	int 10h
	pop cx
	xchg ax,di
	add ax,bp
	add dx,si
	dec si
	inc bp
	add cx,byte 40h
	inc bl
	jnz next

fill	mov ax,3
	int 33h
	shr bx,1
	jnc draw
	pop ax
	int 10h
exit	ret

draw	push cs
	pop ds
	mov ax,cs
	add ax,4096
	mov es,ax
	xor di,di
	mov si,area+321

line	mov bx,320
	push cx
plot	mov bp,KONST_P
	push bx
	push dx
	xchg ax,dx
	imul ax
	idiv bp
	xchg ax,bx
	mov ax,cx
	imul ax
	idiv bp
	add bx,ax
	pop dx
	mov bp,KONST_G
	mov al,[si-321]
	sub al,[si]
	sbb ah,ah
	push dx
	imul dx
	idiv bp
	sub bx,ax
	lodsb
	sub al,[si]
	sbb ah,ah
	imul cx
	idiv bp	
	pop dx
	sub ax,bx
	pop bx
	add ax,KONST_S
	add ah,ah
	jz done
	sbb al,al
	not al
done	stosb
	dec cx
	dec bx
	jnz plot
	pop cx
	inc si
	dec dx
	cmp di,320*200
	jc line	

	push es
	pop ds
	mov ax,0a000h
	mov es,ax
	xor si,si
	xor di,di
	mov cx,320*200/2

	mov dx,03dah
lead	in al,dx
	test al,8
	jnz lead
fall	in al,dx
	test al,8
	jz fall

	rep
	movsw	
	jmp fill

area