Mail Archives: djgpp/1996/11/15/19:12:15
From: | Glen Miner <gminer AT ca DOT newbridge DOT com>
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Newsgroups: | comp.os.msdos.djgpp
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Subject: | Re: Memory Protection
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Date: | Fri, 15 Nov 1996 12:37:02 -0500 (EST)
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Organization: | Newbridge Networks Corporation
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Lines: | 24
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Message-ID: | <Pine.SUN.3.90.961115123053.21409A-100000@coop10>
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NNTP-Posting-Host: | 138.120.136.238
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Mime-Version: | 1.0
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To: | DJ Delorie <dj AT delorie DOT com>
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In-Reply-To: | <199611151733.MAA21304@delorie.com>
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To: | djgpp AT delorie DOT com
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DJ-Gateway: | from newsgroup comp.os.msdos.djgpp
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> > Ahh, this makes sense now. I suppose my next question is: how does the
> > dosmem put/get functions get around this? Do they resize before and
> > after? Wouldn't this be painfully inneffeicient?
>
> They use a different segment, which overlaps the DOS memory instead of
> the program's memory.
Ahh, I see. I don't know much about pmode programming, but I know real
mode inside and out, and this is starting to make more sense.
> For further protection, you can create a segment that covers only the
> video memory and use that instead.
How would this be done? This would be ideal; if you could setup another
segment (a 64k window to vidoe memory), and it would be "unprotected",
then you could just use the movedata function with that segment's
selector, right?
Peace
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