.model tiny
.code
.startup

	mov ah,0fh			;stary mod
	int 10h
	cbw
	push ax
	mov al,13h			;novy mod
	int 10h

        std				;opacny direct
	cwd				;vynul dx
	xor bx,bx			;vynul bx
	mov cx,0ffffh			;nastav cx -1(ffff)
	mov si,offset(diff+8)		;si <- diff+11 (0)
	mov es,[si]			;es <- [si]

step:	add dh,[si]			;dh+[si]
	add cx,[si-2]			;cx+[si-2]
part:	mov ax,1010h			;ax=1010h
	int 10h
	inc bx				;bx+1
	test bl,03fh			;bl*3fh -> pouze flagy
	jnz step			;bl=3f skok step
	;lodsb				;si-1
	lodsw				;si-2
	and bh,bh			;bh*bh
	jz part				;bh=0 skok part

	xor cx,cx
line:	xor ah,ah
	xchg ax,bx
	mov di,199*320
	mov ax,255
	sub ax,bx
	test al,1
	jnz evenx
	mov di,256
	mov al,64
	mov cl,199
	add ax,bx	
evenx:	cwd
	xchg ax,bp
	mov ax,di
	mov si,320
	div si
	sub cx,ax
	jnc yfix
	neg cx
	neg si
yfix:	mov al,1
	xchg ax,bp
	sub ax,dx
	jnc xfix
	neg bp
	neg ax
xfix:	cmp ax,cx
	jc lfix
	xchg ax,cx
	xchg si,bp
lfix:	mov bh,al
	mov dx,cx
	neg dx
	sar dx,1
	mov ax,cx
	xchg ax,bx
	inc cx
plot:	stosb
	inc di
	add di,si
	add dl,ah
	adc dh,0
	jnc skip
	add di,bp
	sub dx,bx
skip:	loop plot
	inc al
	jnz line	

	mov ah,8
	int 21h
	pop ax
	int 10h
	ret

	;  0 1 2 3 4  5  6  7 8 9 10 11  12
diff    db 0,0,1,1,-1,-1,1, 0, 0, 0a0h
end