Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!cbmvax.cbm.commodore.com!daveh
From: daveh@cbmvax.cbm.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: GVP 68030 reviewed in Sentry / 68040
Message-ID: <8906131337.AA06462@cbmvax.UUCP>
Date: 13 Jun 89 13:37:42 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 18

Sounds like you've got some good rumor sources.  Of course the '030
has an internal harvard architecture, so you'd have a good reason to
expect the '040 to have one as well.  The '040 design does look alot
like an 88x00 system; separate MMU/ATC/Cache units for both I and D,
4-set associative like the 88200.  Also, they're physically mapped,
as opposed to the logically mapped caches on the '030, which is 
required for bus snooping, and can result in fewer cache flushes in
a system that knows how to use a physical cache.  I guess the main
point against physical caches to date has been the speed loss, but
Motorola seemed to have that pretty well taken care of in the '030
anyway, so the '040 should be just fine.

The Intel thing with it's single big cache seems an obvious 
compromise to the world of MS-DOS.  Extra wide buses to try and
wring more performance out of it is a good idea, but it all 
ultimately gets crammed into the internal 32 bit bus it looks.

-Dave