Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!oliveb!amiga!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 32 bit questions
Message-ID: <6392@cbmvax.UUCP>
Date: 24 Mar 89 03:40:29 GMT
References: <1455@wpi.wpi.edu>
Organization: Commodore Technology, West Chester, PA
Lines: 43

in article <1455@wpi.wpi.edu>, pawn@wpi.wpi.edu (Kevin Goroway) says:

> I was just told that Commodore displayed a 25 Mz version of the 68020 board
> at the Hanover Show in Germany?  Is there any truth to this?  

Not sure just what was shown in Germany, other than of course the stuff that
everyone already knows about.

> Second...
> I have SetCPU in startup sequence, no options...What are the options?  Are
> there any reasons to use them? Dave?

That depends on the version of SetCPU you're using -- the latest from the net,
V1.4, does lots of interesting things if you're on a 68020 or 68030 system.
Typing "SetCPU ?" will give you a list of options, something like this:

	SetCPU V1.4 by Dave Haynie
	Usage: SetCPU [INST|DATA] [[NO]CACHE|[NO]BURST]
	              [[NO]FASTROM [TRAP]] [NOMMUTEST]
	              [CHECK 680x0|68851|6888x|MMU|FPU]

So if you've got a 68020, you can turn the instruction cache on and off.  On
an '030 system, you may be able to turn the data cache and cache line burst
mode on and off (you will if the '030 card designer did The Right Thing). If
you have an MMU in your system, FASTROM will build a 32 bit image of the 
system ROM and then use the MMU to translate that image back to $00FC0000,
so you get full speed on ROM based things.  Normally FASTROM sets up the
MMU for 24 bit address wrapping, but with the TRAP option, addresses are a
full 32 bits long, and any access beyond $00FFFFFF will result in a 
privilege violation exception (popularly known as GURU #2).  The NOMMUTEST 
option turns off the MMU test, since some 68020 boards have design errors
that prevent proper testing for MMUs (if yours does, NOW would be a good time
to prod the manufacturer for a fix to this problem).  The CHECK options let
you check for a particular Motorola chip, or in general an MMU or FPU.  If
you're using an A2620, this will let you do stuff differently in a Startup
Sequence depending on whether you're booting with the 68020 or the 68000.

> thanks!

-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
              Amiga -- It's not just a job, it's an obsession