Rik Ling wrote in message <35eede43.0@news.povray.org>...
>A few more observations:
>
>Regarding the "small percentage" of users who stand to benefit from any
>3DNow! optimizations, let me remind people that intel will be rolling out
>their MMX2 instruction set as of Q1 1999, and it too will have the same
>kinds of SIMD FP instructions as the 3DNow! set has today.  Also, CPUs with
>3DNow! will also be produced by Cyrix and IDT/Centaur.  Eight to twelve
>months from now, every new x86 compatible processor sold will have these
>capabilities.


I apologize, it seems I haven't been watching the news lately :) Anyway I
still
think that nerve-breaking assembler hardcoding for a single platform is
something we just could't demand from the POV-Team. My point of view is
also affected by the fact that it isn't likely I'll be able to afford and
upgrade
in the next two or three years.

>It seems prudent to start optimizing for the K6-2 platform now, so that
when
>MMX2 becomes available the majority of the "grunt-work" will already have
>been completed, leaving only the fine tuning to be done.  Lets face it,
>regardless of whether it's 3DNow! or MMX2 or some sort of extended MVI for
>Alpha, the basic mechanics of the interface will probably remain
consistent.

Well, I am not sure the MMX2, 3DNow! MVI etc. are identical. Well, maybe
they (will) offer similar functionality, but on the coding side of things
they
are, I guess, just different. Also, optimising is very processor-dependent
(things like conveyors, registers, etc.)

>Besides, I own a K6-2-300, and the potential to realize a two to four times
>increase in FP performance just makes me foam at the mouth... :)  I'll
start
>looking into what might be required to do this (although my programming
>skills are a little rusty - this'll be a good refresher)  Anyone who wishes
>to help can contact me at rli### [at] pipcomcom

Well, an unofficial compile made by a group of volunteers is a better idea
than
asking the POV-Team do it and/offer support for it.

>Also, you don't actually need a 100MHz FSB mainboard to run a K6-2-300.  It
>will run quite happily with a 66MHz FSB and a 4.5 multiplier.  Certainly
>your overall system performance will suffer but programs like POV, which
>have a very tight execution loop that has been (hopefully) optimized to
stay
>within the 16 to 32KB of on-chip cache, won't care about that.  66x4.5 (or
>75x4) should yield 95% of the performance of 100x3 in this case.  POV is
>nice that way...
>
>The 2.2volt requirement is a little more tricky, but most newer boards
(even
>the low cost ones) will go as low as 2.1 volts now.  On the whole
>(especially if the 3DNow! instruction set can be utilized for a perfomance
>gain in POV) the K6-2 would probably give the best bang for your buck.
>Also, wouldn't you like that new 500MHz intel katmai processor to REALLY
>scream by using MMX2 in addition to its raw horsepower?
>
>Rik Ling
>Graphics Lurker (and K6 defender)
>rli### [at] pipcomcom
>

Thanks for enlightening me.

Peter.

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