Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 beta 3/9/83; site uthub.UUCP Path: utzoo!utcsri!utai!uthub!thomson From: thomson@uthub.UUCP (Brian Thomson) Newsgroups: net.micro.68k,net.micro.16k Subject: Re: Pre-fetch Message-ID: <221@uthub.UUCP> Date: Thu, 18-Jul-85 13:42:41 EDT Article-I.D.: uthub.221 Posted: Thu Jul 18 13:42:41 1985 Date-Received: Thu, 18-Jul-85 14:35:01 EDT References: <891@bunker.UUCP>, <644@terak.UUCP> Organization: CSRG, University of Toronto Lines: 10 Xref: utai net.micro.68k:719 net.micro.16k:241 Yes, the 32016 does properly handle (i.e. ignore) page fault and protection traps on prefetches, but it still isn't quite perfect. We have seen a 32016 continue to prefetch after partially executing an SVC instruction, such that it uses the old user-mode PC for the prefetch address but does the accesses in system mode. This can be a problem if the system-space address is, eg., a device register or if the page is valid but mapped to nonexistent memory. -- Brian Thomson, CSRI Univ. of Toronto {linus,ihnp4,uw-beaver,floyd,utzoo}!utcsrgv!uthub!thomson