Re: Re: [stella] StellaX PAL detection

Subject: Re: Re: [stella] StellaX PAL detection
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Thu, 31 Jan 2002 22:06:39 +0100
I´m not sure that I have the latest Stella, but it the one I have doesn´t
emulate the 6507 data bus correctly. This is not that hard to do from
scratch, but might be a different thing now, since the whole emulator has

In the latest release version this is still the case, but in the
most current development version it has been fixed. You can
actually "play" Video Pinball on Stella too now. ;-)

And support for the DPC has been added too. Stella's sound
engine isn't capable of outputting the special sound data
yet though, so you won't be able to hear the melody.

Also, doesn´t seem that addressing any RESXX register within 24 cpu cycles
after an HMOVE, leaves the object in the right position. BTW, how PCAE or
Z26 handle this?

The results depend on what was in the corresponding HMPx register
before the HMOVE. I think we have a table for handling that in z26,
which John and I got from systematically trying out all possible
combinations on a real VCS. We only experimented with accesses to one
motion register during the 24 cycles after HMOVE though. So games
that do more accesses, like Kool Aide Man still don't get emulated
properly, and we have to cheat for them.

Therefore it would be nice, if someone with access to the TIA
schematics could have a look at how the horizontal object motion
really works and how accesses to the TIA motion registers are
handled by the TIA. That would be a great help, and might even make
the emulator code a little simpler.

Ciao, Eckhard Stolberg

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