Robert A. Colbert wrote:
>
> >Dark Mage utilizes SC bank-switching, but does not use RAM. I've not
> >been able to successfully use SC RAM at all yet. It always crashes.
>
> Check the source code for Stell-A-Sketch - there is a nifty little >routine I have in there to move a chunk of memory. Feel free to use >it, but be warned that moving a chunk of memory is time consuming :)
Yeah, I'm already pretty familiar with that routine ;) The problem is
not writing RAM access stuff, but re-writing all the *other* stuff I
have that inadvertently causes the game to immediately go wonky as soon
as I merely enable write in the control byte of my WAV file... I haven't
had an overwhelming need to use RAM that has gotten me to the point
where I spend the many excrutiating hours re-writing a lot very touchy
code... The 12 character display in Dark Mage, for example uses a STA.W
extended mode write to zero page for cycle timing purposes... RESCUE has
a ton of that sort of thing. What I really need is more ROM ;) I know
I can write bank-switching code for either the SC or a standard hardware
decode, but I'd like to pack as much as I can into 4K before going that
route. I still have mild hopes that a complete and slick version of
RESCUE will fit...
One 4K game that I've played a bit of recently that is very impressive,
IMO, is Activision's Spider Fighter. That game puts a lot of single
scanline, fast moving, animated stuff on screen without any flicker.
The trick they use is to have one free-moving sprite teamed up with 4
pseudo-free-moving sprites that actually jiggle in horizontal ranges to
give a high-speed illusion that 5 enemies are flying around freely. Some
amazing code that I can't quite figure out, starting right at $F000,
allows all that, plus bunch of missiles to fly as well... Very nice. I
think I should be able to do a decent version of RESCUE in 4K
considering that game as a sort of similar precedent.
--
mor@xxxxxxx
http://www.crl.com/~mor/
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