Re: Apple II Graphics Programming (Assembly)

[Calibrator <calibrator@freenet.de>]

On 8 Jul., 19:21, Toinet <antoine.vig...@laposte.net> wrote:
>
> Why do you want to preserve the different screen holes of the HGR
> screens?

I would do it for speed reasons (see my answer to Mark) but
Rob (ict@ccess) apparently uses them for embedded code.
See this thread:
http://groups.google.com/group/comp.sys.apple2/browse_frm/thread/6764c2d36dd29d52#

> I understand that when you deal with the text screen as useful data is
> recorded there but for high resolution pages where you will probably
> use page flipping, sprites, page erasing, etc. then speed is required
> and Paul's second algorithm is fine.

If speed is very important you would use a line table anyway
and except for the page erasing I don't see why one would
access the screen holes with a sprite routine (or anything
else using the line table) at all.

> If you want to save room, use the routine in ROM. If you want speed,
> forget about the screen holes.

It's always a trade-off of course but if speed is paramount
I claim that bytes written to screen holes are wasted cycles.

bye
Marcus