From:	"John S. Fine" <johnfine AT erols DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: cwsdpr0.exe 4/15/99
Date:	Thu, 15 Apr 1999 14:20:44 -0400
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yjtseng wrote:
> 
> So. May I make a bold conclusion that,  in cwsdpmi.exe, the linear address
> will always equal  the physical address

  I don't think that is true.

  I know very little about cwsdpmi, but unless I am seriously
mistaken in the little I think I know, I have a counter
example.

  I run with QEMM and without QDPMI.  Most, but not all,
addresses are mapped physical==linear.  When I run a
DJGPP program it uses cwsdpmi.  I believe it takes
control from QEMM using the VPCI interface.  Using
VCPI it inherits all of QEMM's mappings.

  My DJGPP programs can see things mapped under QEMM at
the same linear address they had under QEMM, even when
that doesn't match physical address.

  I expect there are many more cases in which cwsdpmi
has mappings that don't match linear vs physical.  Even
if most of the mappings do match, I don't think you can
count on it.
-- 
http://www.erols.com/johnfine/
http://www.geocities.com/SiliconValley/Peaks/8600/

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