Re: Choplifter, still no go on Apple IIc +

[Larry Stedman <stedman@binghamton.edu>]

Michael, I'll have to hunt up the Zip Chip diagnostics and see what it 
tells me.  The IIc+ works fine otherwise...  in fact, one can easily 
tell whether it's in 1 MHz mode or 4 by how fast the Choplifter opening 
demo runs!

Yep, it's definitely replicable.  What's odd is that two different 
Choplifter downloads behave in different ways!  One freezes when the 
tank fires, the other, IIRC, doesn't get that far and dumps me out of 
the program and a P appears on the screen.  

That's why I keep hoping that there's a version out there somewhere that 
would work on a IIc+!!

I have a IIc and IIe and both versions work fine on both, so it's 
definitely something connected with the IIc+ architecture.

Really appreciate all the input and feedback on this thread so far... 
it's been fun--and helpful!

In article <0YudnXxkivqr2OfbnZ2dnUVZ_qyjnZ2d@comcast.com>,
 "Michael J. Mahon" <mjmahon@aol.com> wrote:

> Larry Stedman wrote:
> > Alas, the POKE 48984, 192 or POKE 48984,0 did not work.  Neither did the 
> > new download that Bill posted.
> > 
> > The same thing happens... everything seems to be working properly right 
> > up until the first tank firing and then everything FREEZES.
> > 
> > So, any other ideas?  It'd be great to hear that someone has this 
> > working on iic+ before I put more time frittering into it!
> 
> The POKE is there only to make the BLOAD legal.  If the game
> malfunctions after loading, then there is some other problem.
> 
> I've never seen any documentation on Zip Chip (or //c+)
> incompatibilities, but since it "overloads" a soft switch
> by triggering on multiple consecutive references, there is
> always the (remote) possibility that some programs hit upon
> the magic spell to gain access to its internals.
> 
> Of course, there could also be a bug that is only exercised
> by very few programs.  Such are the hazards of testing as
> a means of determining correctness.  ;-)
> 
> Another possibility is that your machine's accelerator is
> failing in some peculiar way--for example, one of the cache
> SRAMs may have a fault.  It might be useful to run the Zip
> Chip diagnostic program to check out the cache.
> 
> The fact that it always fails the same way at least means
> that you are not chasing something intermittent.  ;-)
> 
> If no one else has a //c+ set up to verify this, I may have
> to figure out where mine is...   ;-)
> 
> -michael
> 
> NadaNet file server for Apple II computers!
> Home page:  http://members.aol.com/MJMahon/
> 
> "The wastebasket is our most important design
> tool--and it's seriously underused."

Larry Stedman
Suburban Milky Way