Re: vm02: calling all IIcs - Take 2

[Tom Greene <tom@cowgod.org>]

On Aug 29, 12:59 am, David Schmenk <dschm...@YUCH.gmail.com> wrote:
> Thanks again to Tom for trying this out.  Maybe I can convince him to
> try this one out:
>
> http://schmenk.is-a-geek.com/tarfiles/VM02ALPHA3.DSK.zip
>
> I also discovered a couple of other issues now fixed.  Certain ROM
> routines will disable interrupts.  Some of my sample classes that call
> ROM routines for low res and hi res graphics all of the sudden stopped
> responding to interrupts.  I now re-enable interrupts after every native
> method.  I also discovered that my comparison opcodes would adjust the
> stack pointer, then compare the values that were now above the stack.
> Tsk, tsk.  When an interrupt would occur during the comparison, the
> values would get trashed.
>
> Glen Bredon wrote a nifty little TSR style program that would hook the
> VBL interrupt to keep time.  His notes mentioned problems with various
> IIc models.  He actually didn't bother calling the mouse firmware to
> service the interrupt on a IIc.  The VBL interrupt would continue
> interrupting anyway.  So I now look to see if any hardware claimed the
> interrupt.  If not, I assume it's the VBL interrupt.  Hope this works,
>
> Dave...

Sure thing... alas I didn't get any better results, it still runs fine
on the IIc+ but freezes on the other two ROMs.

One thing I notice with both versions is that keyboard input seems to
extend the run time a bit. That is to say, if I start the helloworld
program and just let it run without touching anything, it runs for
about 30 seconds before freezing. If I start the program and then
pound on the keyboard continuously, it runs about 35 to 40 seconds.

Tom