Re: GS Emulator

[foegelle@sleepy.cc.utexas.edu (Michael Foegelle)]

In article <2vloo1$jsc@news.service.uci.edu>,
Jimmy Shaw <eaiu184@rigel.oac.uci.edu> wrote:

>However, I doubt if it came be done in the real world.  Apple had teams
>of programmers writing the Mac emulator for the PPC, I doubt it such
>organization is even possible, given the state of the GS; even
>if every single detail on the GS is made available, both hardware,
>software, firmware, rom, etc.  Certainly not a "one-man" project,
>even if it's the fabled BurgerBill.  (This, of course, is not a flame on 
>the various GS programmers, whom I have the utmost respect for.)

I believe the difference here is that the power PC MAC can't really be
considered an "emulator" in the truest sense of the word, since I believe 
it consisted of an entire re-write/compilation of the MAC firmware on the
Power PC so that it runs in native mode.  (I may be totally off on this but
I thought that was part of the idea.)  Granted it still has to emulate the
68030 or whatever processor to run the Mac software, but it's a much more 
integrated system than your typical emulator.  The hardware, etc, was designed
to work Mac-like.

>Then again, the Mac-emulator on the PC, Executor, is being written
>by a small group of programmers, I think.  Heck, if the PC can
>emulate the architecture of the Mac, surely the PPC can emulate
>the "lowly" 65816. :-)

At any rate, I suspect a PC or PPC based 65816 emulator wouldn't be too hard
to accomplish, and emulation rates would be about what our realtime rates are.
GS video could be moderately emulated, but there wouldn't be most of the timing
flags and interrupts available that allow tricks like 3200 color graphics to
work right.  Using a Gravis Ultrasound, the GS sound shouldn't be too hard to 
emulate, but there aren't many PC users with GUS overall..  Still, those 
wanting to run GS software might go buy GUS's just for that purpose.  That 
still leaves emulating all the lousy soft switches and interrupts, not to 
mention having to copy Apple's ROMs to your emulator.  So unless Apple releases
the copyright (unlikely) or someone writes some clone ROMs that can withstand
Apple's scrutiny (even MORE unlikely) that only leaves the people owning a GS
already the opportunity to use the emulator.  

So...  It's a neat idea, I'd love to see it done, but I certainly don't have 
the time right now, and I don't know who else does.  

>Jimmy
>
>--
>Jimmy Shaw				OS/2: It costs less, it does more.
>eaiu184@orion.oac.uci.edu
>--------------------------------------------------------------------------

Michael Foegelle

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