From: hyc@hanauma.jpl.nasa.gov (Howard Chu)
Subject: Re: Whaddabout the so-called Jaguar? (was Re: Atari)
Organization: SAR Systems Development & Processing, JPL
Date: Wed, 16 Dec 1992 00:54:36 GMT

In article <92341.132533U28037@uicvm.uic.edu> Jason Kratz <U28037@uicvm.uic.edu> writes:
>In article <1ftevbINNff9@aludra.usc.edu>, rjung@aludra.usc.edu (Robert A. Jung)
>says:
>>        "The Nintendo chip will allow the Super NES to really take on
>>        Atari's Jaguar system, which is also based on RISC technology

>RISC technology?  Are you crazy?  I can understand them using a 68030 or a 386
>but RISC technology?  Yeah right.  A game machine based on RISC technology
>would cost more than the NeoGeo.  If Atari wanted to make any money off of the
>Jaguar it sure as hell won't have a RISC chip in it.  Check out the price of
>a computer based on RISC processors compared to a 486.  There is a big price
>difference.

You folks seem to be forgetting one of Atari's hallmark design features -
always use dedicated coprocessors for specialized tasks. I'm fairly confident
that Atari is going to stick with a 68030 or some equivalent as the main
processor for any systems they introduce in the near future. They have too
much experience with the 680x0 processor family to just throw it all out and
start from scratch somewhere else. Also, if the new Jaguar is supposed to be
able to play regular ST/Falcon games, it will pretty much *have* to include
most of the elements of an ST or Falcon. (No big deal, seeing that the Falcon
has an "ST-on-a-chip" custom ASIC already...) [I know Motorola and DEC claim
tremendous speeds for their RISC chips emulating other processors, but if
emulation is going to be the primary mode of operation for the thing, it's
silly not to go with the actual chip (unless speeds are vastly improved?).]

Let's go back to the 8-bit Atari designs... Chips like Antic, Pokey, and GTIA,
remember them? These were all microprocessors in their own right, although they
had very limited instruction sets. I think it's very likely that whatever
system we see in the future named Jaguar will include a dedicated video
controller chip that maintains a "program" (i.e., a display list), has a
Reduced Instruction Set, where all instructions execute in a single clock
cycle, and maybe even a fair-sized register file. This is really nothing
tremendously new from Atari's standpoint, they've developed this sort of thing
for years. It's just that nowadays the rest of the computer industry has a
recognizable *name* for what's been around all along...

And finally, even if we're talking about a more mainstream RISC processor,
like an i960 or TI whatever, there's still no reason for it to be the main
compute engine in the system. Indeed, the Intel RISC chips were never intended
for use as general-purpose compute engines and yield pretty miserable
performance when applied to these uses. (Which is why Intel stopped support
of this application mode, and why companies like Alliant that used them this
way have gone chapter 11, even though chips like the i860 and i960 still find
tremendous use as graphics accelerators and system controllers, respectively.)

I think it's safe to say that the words "based on RISC technology" in the
previous quote take a very loose interpretation of the facts...

P.S.: As other folks have already noted, the Atari TT video has 64 bit access
to memory, so it's neither an unusual nor pricey feature for Atari to carry
on into other systems. And re: needing a "blitter from hell" to blit 64 bit
pixels, if they are in fact using 64 bits per pixel - I've already heard
rumors in this regard. I'm sure there will be a monstrously fast blitter in
the Jaguar; I'd bet the cost of a new Lynx cartridge that it'll be there.
-- 
  -- Howard Chu @ Jet Propulsion Laboratory, Pasadena, CA

All true wisdom is conveyed in one-line witticisms.
Newsgroups: rec.games.video