Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!cornell!uw-beaver!tektronix!percival!billc
From: billc@percival.UUCP (William Coldwell)
Newsgroups: comp.sys.amiga
Subject: Re: CMI 68000 2x
Keywords: CMI Processor Accelerator
Message-ID: <1341@percival.UUCP>
Date: 31 Aug 88 01:42:45 GMT
References: <3372@crash.cts.com>
Reply-To: billium@pro-charlotte.cts.com (Bill Blanke)
Distribution: na
Organization: Percy's UNIX, Portland, OR.
Lines: 84

In article <3372@crash.cts.com> billium@pro-charlotte.cts.com (Bill Blanke) writes:

:I was flipping through a magazine and saw an ad for CMI's processor
:accelerator. Its supposed to double the clock speed of the Amigas
:processor from 7.12 to 14.3 MHz. I've got a few questions about it.

 Hope I can answer them...

:(1) Does anybody have this on there Amiga? Has anybody seen it?

 Yes, and I see it every day - whether I want to or not.

:(2) How compatible is it with Amiga software. I remember someone
:    was saying how it was incompatible with dongles. Thats no problem
:    for me though since none of my software is dongled.

 So far, there really isn't anything that it's software incompatable
 with, and the problem with dongles is because they (those pesky software
 people) are using software loops to get the info from the dongle, and
 viola: it's finished twice as fast as it was expecting...

:(3) Does the 2x speed increase affect games. I guess what I'm asking
:   is if Amiga games are timer based (wait 1 second and then do this)
:   or processor cycle based (execute these instructions as fast as
:   you can, then do this-I would have to deal with an arkanoids ball
:   flighing around twice as fast as normal!). If all are timer based
:   (hopefully) does this mean sometimes sluggish games (like Obliterator)
:   would perk up and move more smoothly, but still remain at their
:   current speed?

 Yes, it does affect most games that are not timer based.  Generally making
 them more smoother, rather than "faster".  F-18 and Jet are the same speed,
 just smoother in all of the calculations.  Obliterator is nice, but you see
 a real difference with Barbarian.

:   If they are cycle based is there a way to revert back to 7.12 Mhz,
:   preferably through a hardware switch?

 Would you settle for a software switch? (That's what I do.) - If you
 want to make a toggle, that's fine (unless you work for the FCC, then
 in no means are we condoning such criminal activities...) - just make
 sure that you rip up your warranty card after doing it ;-).  Incidently,
 the Amiga runs at 7.16, not 7.12MHz.

:(4) What kind of speed increase could I expect over the normal 68000 with
:   ray tracing programs, general multi-tasking, Desktop Publishing
:   programs (not moving memory-blitter does that-I mean all the reflowing
:   of text and all the recalculating the program has to do) and
:   Transformer?

 Ok, general rule of thumb:  Anything done with the 68000 is twice as
 fast, especially math calculation functions.

:(5) How much better would the speed increase be with the math coprocessor?
:   Would the coprocessor be available for all programs or just those
:   that are writtin to use it? Would the 1.3 math libraries take care of
:   those that aren't?

 Only programs that use the IEEE libraries for math functions will use the
 68881/2, and no, 1.3 won't make programs that don't use the IEEE shtuf
 use the 68881 - but the ones that do... unreal.  Hey, you turkeys who
 are developing applications that use math functions, check to see if
 there is a MathIEEE resource, and have your routines use IEEE!!!!!
 Otherwise use FFP.  I'll be more than happy to post how to check whether
 there is a 68881 installed!

:If the overall speed increase is good I'd buy one. $200 is a great deal
:considering $$$ for 68020,30....

 The speed is pretty comparable to a 68020 with 16 bit memory, and with
 all of the people who have flooded us with orders, Thanks!

 Bill

 Look, just because I am working for CMI doesn't mean that I speak for
 anyone else here, and they don't speak for me - it's hard enough
 trying to speak for MYSELF!


-- 
    William J. Coldwell - Amiga Attitude Adjuster {aka Software Developer}
    (503) 684-9300 ...tektronix!reed!percival!billc  "Blame the hardware."
           [I break for 14MHz Processor Accelerators with 68881's.]
  Creative Microsystems Inc. / 10110 SW Nimbus Suite B1 / Portland, OR 97223