From: davewt@NCoast.ORG (David Wright)
Subject: Re: Emulator for Amiga?
Organization: North Coast Public Access *NIX, Cleveland, OH
Date: Wed, 16 Dec 1992 04:18:32 GMT

In article <1992Dec14.190929.28143@zip.eecs.umich.edu> dmuntz@quip.eecs.umich.edu (Dan Muntz) writes:
>
>The problem with this is that more people probably have Vectrexen than 
>Amigas (especially when you consider that an A1000, A500, and probably the 
	I think you have over-estimated the # of Vectrex units and
under-estimated the # of Amiga's in the US. The are FAR more A1000's still in
service than Vectrex units, let alone the 500/2000 line.
>Amigas (especially when you consider that an A1000, A500, and probably the 
>A2000 would be too slow).  A 486DX33 is capable of emulating a 4mhz Z80A,
	I don't think the speed makes as much difference on the Amiga. The
68000 used in the low-end Amiga's is MUCH more similar to the 6809 than the
80x86-baed PC's, and so emulating them through software would be fairly
close to real speed. Say 60-75%. Given that the slowest Amiga is running
at 7.14Mhz, and even if the emulation speed was only 50%, you still have over
3.5Mhz of 6809 speed. The Vectrex was only 1Mhz wasn't it?
>really kills the emulation speed.  Assuming the 6809 emulator works
>well on the 486, the best choice would probably be the 486 w/DOS (no
>OS overhead :-).  Unfortunately, for portability the BIOS calls should
>be used for graphics.  Anyone want to suggest what screen resolution would
>be necessary to get decent results?

	And this is another problem with an emulator on PC's. The primary
CPU would have to do all the graphics work, unless the emulator only ran on
high-end display cards with their own processor. ALL of the Amiga's have
graphics coprocessors that could EASILY keep up with Vectrex-class
monochrome line drawing, without using even 1 primary CPU cycle. I would
be willing to bet that I could even get someone to emulate the color of
the Vectrex overlays by masking out bitplanes. The 3-D stuff could be
done using any of the 3-D gogles that are available.

	And of course there is still the sound problem. You would need some
kind of sound board on the PC to generate Vectrex quality sound, and again
the primary CPU would have to do this as well as the CPU emulation and
graphics. This would NOT be fun to do on anything but a fast '386 of '486
system.

	You have to remember that all Amiga models except the 1200 and
4000 are only capable of handling bitplane graphics (with the stock
displays), not chunky pixel, and that where bitplane graphics really shine
is doing mono & low-color line drawing.
	If I wasn't busy working on MUDs, and I had a free implementation
of a 6809 assembler to work from I would work on this myself. I suspect
that the only reason there ISN'T one for the Amiga already is the very low
number of people who even know what a Vectrex IS anymore. (I have had
people think mine (when it was turned off) was a Mac that I painted
black). Personally, I would like an emulator on my Amiga so I could get
rid of the annoying screen flicker in some games, and get nice crisp sound,
I have yet to get rid of that background hum by grounding various places
inside as was posted here earlier....


						Dave


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