Article View: comp.lang.asm.x86
Article #201Re: Big Real Mode above 4Gb
From: MGMidget
Date: Sun, 08 Sep 2002 16:55
Date: Sun, 08 Sep 2002 16:55
34 lines
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3228 bytes
"Frank Kotler" <fbkotler@attbi.com> wrote in message
news:3D7B1CC2.10203@attbi.com...
> MGMidget wrote:
> > I understand the basic principles of Big Real Mode where the selector
limit
> > is set to 4Gb. Is there a way to have the base be at 4Gb and the limit
at
> > 8Gb? Would this work, and what would the problems be? There is no OS
> > involved at the time I'm trying to execute this code.
>
> When you return to RM, addresses are calculated by segreg * 16 + offset
> again, so it wouldn't work. If it did, how would you address it?
>
> Best,
> Frank
I wanted to have the Real Mode memory addresses act like they are remapped
to the 4Gb to 8Gb region (sort of like V86 mode I suppose?). This would
allow me to reuse/recyle some Big Real Mode code that needs to address above
4Gb.
I was trying to either:
1) get an address remapping capability to work so that data access in
the 0-4Gb region is really remapped to 4Gb-8Gb in Big Real Mode.
2) or, find a way to extend the address to 36 bits in Big Real Mode -
perhaps via Paging in Big Real Mode (?).
Thanks,
-- TW
Technical Details
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 114917,c9b261141e7752 X-Google-Attributes: gid114917,public X-Google-Thread: fdc9c,c9b261141e7752 X-Google-Attributes: gidfdc9c,public X-Google-ArrivalTime: 2002-09-08 10:55:15 PST Path: arc1-ca.pugleaf.net!archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!news-out.nuthinbutnews.com!propagator2-sterling!news-in-sterling.newsfeed.com!news-in.nuthinbutnews.com!feed.textport.net!sn-xit-02!sn-xit-06!sn-post-01!supernews.com!corp.supernews.com!news.crayne.org!clax86!robomod!not-for-mail From: "MGMidget" <twestern@earthlink.net> Newsgroups: comp.lang.asm.x86,intel.microprocessors.pentium_iii Subject: Re: Big Real Mode above 4Gb Approved: CLAX86 Moderators <ccrayne@crayne.org> Date: Sun, 8 Sep 2002 16:55:59 +0000 (UTC) Organization: EarthLink Inc. -- http://www.EarthLink.net Message-ID: <M0Le9.15244$LI2.1129658@newsread2.prod.itd.earthlink.net> Sender: clax86@odin.asgard References: <DPwe9.14205$6i4.1145514@newsread1.prod.itd.earthlink.net> <3D7B1CC2.10203@attbi.com> Reply-To: "MGMidget" <twestern@earthlink.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-CLAX86-Policy: http://www.pacificsites.com/~ccrayne/clax86.html X-CLAX86-Faq: http://www2.dgsys.com/~raymoon/x86faqs.html X-CLAX86-Info-1: Send submissions to comp-lang-asm-x86@moderators.isc.org X-CLAX86-Info-2: Send technical complaints to ccrayne@crayne.org X-CLAX86-Info-3: Send complaints about policy to ccrayne@crayne.org X-Comment: moderators do not necessarily agree or disagree with this article. X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-MailScanner: PASSED (v1.2.6 40687 g88Gb0uA049426 mailbox1.ucsd.edu) X-MailScanner: Found to be clean X-SpamAssassin: not spam, (##) score=1.8, required 5, FROM_NAME_NO_SPACES, KNOWN_BAD_DIALUPS X-UIDL: CkT"!0&3!!ccM!!>ib"! X-Complaints-To: abuse@supernews.com Lines: 35