Re: Asteroids hack

> 1) More common. Go with the bigger target market...
> 2) Already has all the analog sound hardware for Asteroids.

Except there'll be many missing Deluxe sounds, and the Asteroids sounds
can be approxmiated with the pokey that's on the Deluxe.

> I didn't want to try to recreate the analog sounds in hardware, and I didn't
> want to hack the Asteroids Deluxe sound routines into LL or AST, so I liked
> the Asteroids board. (I figure that the Asteroids thrust sound will be OK
> in LL)

Avoiding making software changes and doing it in hardware, eh? ;-)

> [Overclocking] - Ed and I talked about this a long time and figured the best
> way to do it would be to roll something like http://www.free-ip.com/6502/
> into a Virtex or Spartan FPGA. Plenty fast then. :-) The lack of BCD would
> be a problem for Atari stuff IIRC, so that would have to get fixed.

Apparently the 65C02 has higher clock rate versions, too. I'm just looking
for a source for them.

> [Overclocking] - If my memory serves, Asteroids runs essentially async from
> the VSM.

Completely async. It runs at exactly 45 redraws per second, which is
around 22.2ms. It's actually computed in foreground code and the
foreground code spins on a semaphore that's clocked off the NMI.

> from the IRQ for the CPU?)-- if the game code has lots more cycles to do
> stuff because of a faster CPU, all the better.

Bingo. Sometimes the 1Mhz Asteroids would start flickering if there was
lots of activity. As it's coded now, if the foreground code can't do it
fast enough, it'll effectively "skip" drawing a frame.

-->Neil

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Neil Bradley C++ - A language where you can make your
Synthcom Systems, Inc. privates public
ICQ #29402898

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Received on Sat May 5 16:12:49 2001