Re: Revisited: Sega XY freeplay

Clay Cowgill wrote:
> Once you locate the coin switch reads, just step through the code and fine
> the timing loop. From there, hack on the ROM image (I wish MAME's debugger
> would let you modify program memory...) and test to make sure you killed the
> timer. ;-)
>

It is pretty easy to recompile MAME and change all the ROM loader functions so that
you can edit them in the debugger. If anyone needs help with this or is interested
I can help with any questions.

The biggest PITA about the MAME debugger is that it will only break on 'writes' to
a memory location and not on a read :-( (Unless this has changed in the last
3 months).

> Since I never seem to get around to this, I'll look for my disassemblies of
> all the G-80 stuff. I think I noted the coin-timer in at least one...
> Probably a two-byte patch to just jump over it...
>
> -Clay
>
> > ----------
> > From: Mark Jenison[SMTP:jenison@cig.mot.com]
> > Reply To: vectorlist@lists.cc.utexas.edu
> > Sent: Wednesday, September 01, 1999 9:20 AM
> > To: vectorlist@lists.cc.utexas.edu
> > Subject: Revisited: Sega XY freeplay
> >
> > I had to resubscribe to vectorlist today...apparently I was unsubscribed
> > (and
> > just after my post about the way reply was set up...how coincidental!). I
> > thought the list was awfully quiet. :-)
> >
> > Does anyone understand how Sega implemented the timed-coining for their
> > vector
> > games? Is it all in software, or is it hardware?
> >
> > ----------------------------------------------------------------------
> > Mark Jenison E-mail address: jenison@cig.mot.com
> > Cellular Infrastructure Group Motorola--Arlington Heights, IL
> > ----------------------------------------------------------------------
> >
Received on Wed Sep 1 14:11:55 1999