Path: utzoo!yunexus!geac!daveb
From: daveb@geac.UUCP (David Collier-Brown)
Newsgroups: comp.arch
Subject: Re: Is the Intel memory model safe from NO-ONE ?!?
Keywords: descriptors, segments, performance
Message-ID: <2726@geac.UUCP>
Date: 10 May 88 13:14:31 GMT
Article-I.D.: geac.2726
Posted: Tue May 10 09:14:31 1988
References: <1806@obiwan.mips.COM> <2904@omepd> <353@cf-cm.UUCP> <22830abd:a11@snark.UUCP> <52404@sun.uucp> <2430@louie.udel.EDU>
Reply-To: daveb@geac.UUCP (David Collier-Brown)
Organization: The Geac Segment Descriptor Department.
Lines: 15

In article <2430@louie.udel.EDU> rminnich@udel.EDU (Ron Minnich) writes:
>Before any one goes off the handle about cost, remember the cost
>of all those programs that duplicate this stuff in C code. 

  Actually I prefer to deal with bounds-checking at the
segment-descriptor level: shrinking a descriptor around my array
makes it possible for the hardware (memory managment unit) to do the
checks in parallel with the fetch...  All I get is a need for an
exception handler (once), not a need to write or generate a
test-and-branch after every reference.
-- 
 David Collier-Brown.                 {mnetor yunexus utgpu}!geac!daveb
 Geac Computers International Inc.,   |  Computer Science loses its
 350 Steelcase Road,Markham, Ontario, |  memory (if not its mind) 
 CANADA, L3R 1B3 (416) 475-0525 x3279 |  every 6 months.