Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!rutgers!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: A3000 DATA Cache (Can we PLEASE Settle this?)
Message-ID: <22458@cbmvax.commodore.com>
Date: 14 Jun 91 15:54:45 GMT
References: <1991May26.091925.20814@news.iastate.edu> <21999@cbmvax.commodore.com> <274.2857ae21@intersil.uucp>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Distribution: na
Organization: Commodore, West Chester, PA
Lines: 49

In article <274.2857ae21@intersil.uucp> hamilton@intersil.uucp writes:
>In article <21999@cbmvax.commodore.com>, daveh@cbmvax.commodore.com (Dave Haynie) writes:

>> Under 2.02, it's supposed to default to 

>> 	(INST: CACHE BURST) (DATA: CACHE NOBURST)

>> In SetCPU's words.

>Under ever incarnation of 2.0 I've ever seen, 

Which tells me nothing.  Until recently, modern versions of 2.0 set things up
the way I mention here.  I think recently, they have changed things around 
some.  I believe the ROM now boots you with the I-Cache on, the D-Cache off.
That's so you can still boot cache-sensitive 1.3 autoboot games directly from
floppy, and they'll still work (at least, as well as they would with I-Cache
enabled on 1.3).  The SetPatch program, the first thing run by the OS, will
immediately set things back the way Bryce and the boys like them, which, last
I checked, was "(INST: CACHE BURST) (DATA: CACHE NOBURST)".  

>my machine has always booted with : (INST: CACHE NOBURST) (DATA: NOCACHE 
>NOBURST) in (Set)CPU's words.

I can think of three reasons this might be happening:

1) The software guys changed it and didn't tell anyone.

2) You're running a really old version of 2.0x.

3) You have the latest ROM image on disk, but an old version of SetPatch.

4) You have "SetCPU data nocache" or some-such buried somewhere in your
   startup-sequence.


>Performance does increase when I turn on the datacache and a little more
>when I enable burst modes, but why don't they come up enabled on my machine
>(and, it seems like, most everyone elses)?  

I don't know about everyone else, you're absolutely the first person I have
heard from who's claiming things don't come up correctly under 2.0, but of
course, you didn't say which 2.0.  I don't recall exactly when the cache
stuff was settled on.


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: hazy     BIX: hazy
	"This is my mistake.  Let me make it good." -R.E.M.