Re: MAME For IIGS?

[spec@vax2.concordia.ca (Mitchell Spector)]

In article joe@smoe.com (Joe Seeley) writes...

>Why not?  What excuse is there for no port of this to the IIGS?  Are there 
>any remaining developers out there with the requisite greatness of soul to 
>do this?

    The problem is (or would be, if someone made an attempt at a port)
the hardware limitations of the Apple IIgs. There are two major ones
which would make porting MAME virtually impossible:

SPEED:
-----

    Emulation through software requires extensive CPU power and raw
speed, which unfortunately, the IIgs has very little of. The stock
machine has a clock speed of just 2.6 MHz--which although is quite
noticably faster than a plain 68000 or 8086 running at the same speed,
is still quite sluggish. Add to that the bus is running at only 1 MHz
(the speed at which the computer draws to video) with no blitter or
sprites to help it along. There is FillMode, but I can see no way it
would help in this situtation.

    Certainly an accelerator board would help (especially those like
mine that have been pushed to run at 15 MHz) but the machine is only
speeding things up through a caching method; it still drops back down
to 2.6 MHz at times and the bus is certainly still running at a mere
1 MHz. Decoding JPEG images, for example, with my 15/64 Zip still takes
an incredibly long amount of time--decompressing very large ZIP or LHA
archives slows things to a crawl too.

    You *might* be able to gain some advantage by using plug-in cards
for the classic Apple II, using real hardware instead of emulating it.
Examples would be Z80 processor cards and sound cards which used the
General Instrument AY-8913 chip (I know many dozen arcade games used
those two, often together). Combining this with a high speed Zip GS
or TransWarp GS, and having the emulator skip several graphic frames,
you might come close to pulling it off (for some of the simple games
from the late 70's and early 80's at least).

GRAPHICS:
--------

    The Apple IIgs supports only two resolution modes--320x200 and
640x200, neither of which are suitable for the types of odd custom
modes most arcade games used. Even if you used either of these, in
say a stretched or partial screen view, you still only have access
to 4 or 16 colors without limitations. You can play with multiple
palettes for up to 256 colors in the 320 mode, but many games used
more than 16 colors per scanline. Again, for older games which used
low resolutions and small color palettes you might be able to get
away with it. In the end though, a Second Sight video board would
probably be required but few people own one and programming the
board is almost as difficult as task as porting MAME! ;-)

>Heck, the source is freely available.  There are versions for seemingly every
>somewhat modern platform under the sun including BEOS, Amiga and the Acorn
>(who ever even heard of that)?

    Well based on the above limitations, and the fact there are very
few developers left in the Apple II world, I see very little hope of
this project coming to life. I would _love_ to see it done, even if
just for the sake of doing something people think are impossible on
an Apple II, but in the meantime, I run it on my Pentium system.

    Note I said it is virtually impossible, but _not_ impossible.
Mike Searl wrote a Nintendo Gameboy emulator completely through
software that runs on the IIgs as one example (it doesn't support
sound yet and noticably slow, but it proves you can write software
emulators for this platform. Now if only he'd release it :). There
is also a rumour a B&W Macintosh emulator is being worked on, but
I'm rather doubtful it exists.

>The only thing I have noticed in this group the last two years running is an
>unusually high BS to signal ratio thanks to Tweedle Dee and Tweedle Dum.  The
>group is well nigh approaching oblivion.  Do something (constructive) about 
>it before it is too late!

    The only major constructive things being done presently, that I can
think of, is the game port of Bomberman coming from Ninjaforce (which
should be ready by the spring) and Marinetti, the TCP/IP stack which is
being further worked on. The GS/TCP project and Wolfenstein 3D port seem
to have fallen into permanent limbo.

    Compared to other orphaned platforms out there, development in the
Apple II world has come to a stand-still. I still hold a great interest
in my Apple IIgs (and other II's) and new software is what is will
ultimately keep my interest level up. comp.sys.apple2 is my link to
the II world, but with not much happening except fighting and other
noise, my interest is starting to dwindle (seeing the remaining users
and developers do nothing but fight and talk about other things does
little to spark anyone's interest I'd imagine).

>If you don't know what MAME is, this site may be of use:
>
>http://www.xs4all.nl/~delite/arcade_mame.html

    For those who are reading the above and haven't a clue what 
this "MAME" is, it stands for "Multi Arcade Machine Emulator".
It emulates all the hardware parts of stand-up arcade boxes
from the late 70's right up to late 80's, you just supply the
ROM firmware images (much the way XGS or Bernie to the Rescue
functions, although obtaining ROM images are more difficult).
There are currently over 300 classic arcade games supported
in the in PC port. It emulates _everything_, from the DIP
switches on back of the games to inserting quarters. :-) The 
graphics, music and sound-effects are often 100% identical,
and bring back a lot of memories!

Mitchell Spector
spec@vax2.concordia.ca