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From: markp@valid.UUCP (Mark P.)
Newsgroups: net.micro.68k
Subject: Re: 68030 data cache vs. IO devices
Message-ID: <709@valid.UUCP>
Date: Fri, 10-Oct-86 17:49:49 EDT
Article-I.D.: valid.709
Posted: Fri Oct 10 17:49:49 1986
Date-Received: Sat, 11-Oct-86 21:35:06 EDT
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Organization: Valid Logic, San Jose, CA
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> [stuff deleted]
> 
> Your second problem raises another question.  What happens if one of the 16
> bytes crosses a page boundary?  Does the slurping stop at the page boundary,
> or does the 68030 try to read from the next page?  Without thinking about it
> deeply, it seems possible that this could cause problems if the next page
> isn't mapped, or is mapped to an I/O device.
> 
> 						John Witters

This is physically (pun intended) impossible, as cache block transfers are
necessarily aligned to block-aligned boundaries (i.e. transfer always starts
with A<3..2>=00).  So as long as you don't use 8-byte or smaller pages,
which you probably won't, you're okay.

	Mark Papamarcos
	Valid Logic
	hplabs!ridge!valid!markp