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Mail Archives: djgpp-workers/2001/04/25/16:44:04

Date: Wed, 25 Apr 2001 23:39:43 +0300
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
Sender: halo1 AT zahav DOT net DOT il
To: "The Owl" <theowl AT freemail DOT c3 DOT hu>
Message-Id: <6480-Wed25Apr2001233942+0300-eliz@is.elta.co.il>
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CC: sandmann AT clio DOT rice DOT edu, djgpp-workers AT delorie DOT com
In-reply-to: <3AE5877C.29248.5DE2385@localhost> (theowl@freemail.c3.hu)
Subject: Re: win2000/ntvdm/djgpp (fwd)
References: <2427-Tue24Apr2001004115+0300-eliz AT is DOT elta DOT co DOT il> from "Eli Zaretskii" at Apr 24, 2001 12:41:16 AM <3AE5877C DOT 29248 DOT 5DE2385 AT localhost>
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> From: "The Owl" <theowl AT freemail DOT c3 DOT hu>
> Date: Tue, 24 Apr 2001 14:02:36 +0200
> 
> > To get W2K to see it, do we need to do a dpmi_int with the real mode PSP,
> > or a protected mode Int 21 with the PM selector for the PSP?
> 
> pmode int and pmode selector.

Having thought about this, I must admit this worries me a bit.  What
will CWSDPMI do when the application issues a PM Int 21h with the PSP
selector in EBX?  According to what I see in CWSDPMI's sources, it
simply chains to the real-mode handler of Int 21h, i.e. to DOS.  But
DOS doesn't know what to do with a PM selector of our PSP, so it might
become confused, with potentially disastrous consequences (file
operations will begin to fail, memory allocations might not work,
function 4Ch could hang, etc.).

Charles, am I right about what CWSDPMI will do, or did I miss
something?

So could we please talk about this some more?  Why do we need to issue
a PM interrupt, and why do we need to use the PM selector of our PSP?
Isn't __dpmi_int with the real-mode PSP segment good enough?

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