Re: Request a discrete refresh circuit schematic

[heuser.marcus@freenet.de]

Knut Roll-Lund wrote:
>
> To save a little logic he made all graphics programming a nightmare...
> :-)

The addressing of the video memory isn't that bad, IMHO.
For anything speedy you need an address table anyway and it does not
matter what addresses are in it.

Or do you really want a (slow) multiply by 40 for each line?

In any case you actually *have* lines with 40 bytes in the standard
hires graphics mode - which can't be said of other popular computers of
the time *cough* C64 *cough*...

The color generation and its effect of the video memory organization
(two bytes to form seven pixels, the color bit etc.) is an entirely
different case but AFAIK completely independent of the memory refresh.
But you can do a lot with masks and tables, too.

The 8-bit Ataris for example have cleaner video modes (linear video
memory, "better" color generation via color palette registers) but they
are not necessarily faster when doing the same type of hires graphics
and certain things are even beyond them.


> I was wondering why, but assuming it saved some IC's, and could until
> now not see what would make it worthwhile.

I guess even Woz didn't foresee how fast hires graphics would
eventually be when he made his concept.
 
bye
Marcus