Re: Hopefully last dumb newbie question.

[Jon Christopher Co <jon@tridel.net>]

Slick wrote:


> Now the question. What exactly does the Alternate Display Mode DA do? I think it has
> something to do with the secondary text screen (Address $800-C00 on earlier models),
> but am not sure. None of the books at my library have anything about it. I do know
> about the shadowing to banks $e0 and $e1, and have looked at assembly language
> programming on the IIGS. I just never had the money to buy ORCA or APW. I've used
> the Hyper C (ProDOS 8, and free) assembler to write programs.

You are right there.  since the GS does not support the secondary text screen, they
placed a DA which simulates this support.  I think (not sure) all it does is copy the
data from $800-$COO into text memory to make it visible..  which i think is not on
$800 anymore.