A forthcoming Intellivision Console Emulator for Atari!
(And no, not just for CT60 this time!)
The Atari scene has been getting back into emulation of other hardware in a
fairly big way recently. Thanks to the efforts of Peter P. we've had a
couple of gaps in the emulator inventory for Tos machines plugged. I'm
referring of course, to the Commodore 64 emulator 'Frodo', and the 'SMS
Plus' Sega Master System and Gamegear emulator both ported by him. We took a
look at Frodo in the last issue of Alive, and SMS Plus is getting due
consideration elsewhere in this issue.
The only downside for many people, is that both of these emulators are C
language ports, and need some serious power to run decently. An '060 based
machine is highly recommended, perhaps even compulsory, which does not help
those people who chose not to go down the CT60 route.
But now, there is a third emulator for Tos machines, of foreign hardware,
and this one won't need such a high level of power to decently run it.
I found this by chance, browsing Pouet.net, and a link in one of the one-
liners led me to a picture of what was described as an Intellivision Console
emulator, running inside an Atari ST emulation, on a Game Park GP32! Apart
from the insane level of nesting applications in an onion skin like fashion,
the fact that there was a new and previously unknown emulator for Tos
machines led me to follow up on the story.
The Mattel Intellivision was produced in response to the success of the
Atari VCS console, with the first test marketing done in 1979, and going
properly on sale in 1980. It was the first 16-bit console, with a General
Instruments 16-bit 1 Mhz 1610 microprocessor. This was followed by a 4K
internal ROM operating system and with 2K RAM. The hand controllers went a
fair bit further than the VCS with a 12 button keypad.
Graphically, it displayed a 159 by 96 pixel background resolution in 16
colors and with 8 moving objects. The sound was a fairly standard three-
channel music generator.
It rise and fell with the fortunes of the early videogame boom and crash,
effectively going bust by 1984, although it did have an afterlife, and some
limited production afterwards. In fact, it got to the end of the 1980's
before the plug was finally pulled.
Since then, there has been a keen collectors and nostalgia scene, and
continued interest in the old games, and emulators for the system coded for
the mainstream. There are even some homebrew efforts, and I saw one such of
these, in the form of a demo made for it at one of the ALT Parties.
Interestingly, it turns out to have been made by the same guy, who is coding
this Atari emulator.
I backtracked the Pouet picture to a website, and found that a nice guy
called Arnauld Chevalier, or 'Knox' was behind all of this. He also had some
interest in the Atari ST as well, having done some GFA Basic code for that
machine. At this point, I decided to drop a line to him.
As he is a gentleman, Arnauld soon got back to me. Yes, he had heard of
Alive! even read the odd issue or two, what a hero!
"Your name -- or at least the 'CiH' signature -- does actually sound
familiar. I've read a couple of Alive issues, which is definitively a great
diskmag. Yes, I'm the guy who's writing this Intellivision emulator for
Atari ST. It's called "AtarInty" (how original, hu?) and I'd say the current
version should be considered as some Alpha/pre-Beta kind of stuff."
"Below is a rough evaluation of current emulation accuracies:- CPU : 95%-
Audio : 99% (which was easy since both machines share the same soundchip!)-
Video : below 70% Right now, the biggest flaw probably is the lack of
sprites collision detections, which are performed by the Intellivision
hardware. Most games are not yet playable because of that."
"AtarInty was tested only once on my real 520STF. All other tests were
conducted on Steem, emulating a 520STE. But the final version will probably
require 1 Meg. It's very unlikely to run on Falcon, as I simply never had a
chance to write any code on it and do not know its hardware specificities.
(It will be released under GPL, anyway.)"
"The project has been pending for a while, but I'm planning to release
something before the end of the year. Well, I should better hurry... I'd be
glad to send you a ST disk image with the last version if you want, but I
can't right now. (It's on my laptop and I don't have it handy.) Thanks for
your interest and keep up the good work! -- Arnauld"
Which would seem to satisfy my curiosity, apart from one small point. How
fast is it going to run? He's talking about the ST as the platform of choice
after all. So I wrote again...
"Out of interest, what sort of speed are you getting for the emulation,
assuming you are using an 8mhz 68000 ST as a reference?"
"I haven't done any precise benchmark, but many games are running at 100% ona
standard 8mhz 520ST, with 25 frames per second (instead of 50 for a
PAL/SECAM Intellivision). Some slowdowns occur when a complex screen is
drawn, though. It really depends on the video output complexity. Also, I'm
not even using the blitter, so everything's done by the 68000 for now.
So it won't need a CT60 after all! It looks like a properly hand-coded
effort, rather than a port. I'd guess it'll be something like "Specci" on
the ST and Falcon, with mostly full speed capable on the ST, and full speed
on the Falcon and other 16mhz machines.
There is a rather nice website, in French and English, with information, and
some home-made Intellivision roms, at:- http://knox.ac.free.fr
Anyway, there will be a review, when the emulator is released.
Here's a couple of piccies of Arnaud's homebrew stuff, to whet your appetite!
CiH, for the Alive Xmas Special,Dec '05