Re: Prince of Persia for ProDOS? was Re: QIX for ProDOS

[Steve Nickolas <usotsuki@buric.co>]

Recall from earlier in the thread because I have more info.

On Tue, 30 Oct 2012, BLuRry wrote:
> I am slightly more concerned about the use of the aux zeropage and stack -- 
> aren't those off-limits for Prodos apps?

http://mirrors.apple2.org.za/apple.cabi.net/FAQs.and.INFO/A2.TECH.NOTES.ETC/A2.CLASSIC.TNTS/p8026.htm

--quote--
The area from $D100 through $DFFF in bank 2 of the auxiliary language 
card is for the use of third-party RAM-based drivers, to be discussed in a 
future ProDOS 8 Technical Note. At least one version of Apple II SANE is 
configured to load at $E000 in the auxiliary language card, which is 
perfectly acceptable since SANE is part of the system software (it just 
doesn't ship with the system). 
--endquote--

--quote--
The Rule of Auxiliary Memory:  If /RAM is enabled, all
auxiliary memory above location $800 may be used by an application
after first removing /RAM as discussed in the ProDOS 8 Technical
Reference Manual.  /RAM should be reinstalled upon completion.

If /RAM is not enabled, then auxiliary memory above $800 may be
used at the application programmer's discretion, but the areas
marked as reserved must be respected.
--endquote--

Since we don't intend to have a "quit to ProDOS" option, it's prolly safe 
to keep /RAM disconnected and we can prolly step on the Selector when 
we're bootstrapped?

Another source suggested that it might be possible to eat the stack, but 
$0100 and $0101 need to hold the SP or something.

-uso.