Path: utzoo!mnetor!uunet!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.m68k
Subject: Re: 68030 MMU Questions
Message-ID: <3433@cbmvax.UUCP>
Date: 7 Mar 88 21:18:41 GMT
References: <1030@marlin.NOSC.MIL>
Distribution: comp.sys.m68k
Organization: Commodore Technology, West Chester, PA
Lines: 20

in article <1030@marlin.NOSC.MIL>, aburto@marlin.NOSC.MIL (Alfred A. Aburto) says:
> 
> 	Perhaps I'm out-of-luck anyway because the Amiga is multitasking and
> 	task switching without flushing the address translation cache (ATC)
> 	can mess things up.  If this is the case then I'm stuck because the
> 	ATC flushing must be done by the operating system and there is not
> 	much I can do from the user side(except to keep the data cache off).

This shouldn't be a problem.  The address translation cache should be 
flushed on task swap by something like UNIX, where multiple tasks can
occupy the same virtual addresses at the same time.  But on the Amiga, there
should be a direct mapping of virtual to physical addresses.  I'm no wiz
on the software aspects of the MMU, but that sounds like the main reason
for the cache flush.  Are there any others?

> 	Al Aburto
-- 
Dave Haynie  "The B2000 Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {ihnp4|uunet|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
		"I can't relax, 'cause I'm a Boinger!"