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Mail Archives: djgpp-workers/2001/05/01/07:31:39

Date: Tue, 1 May 2001 14:05:42 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender: eliz AT is
To: The Owl <theowl AT freemail DOT c3 DOT hu>
cc: sandmann AT clio DOT rice DOT edu, djgpp-workers AT delorie DOT com
Subject: Re: win2000/ntvdm/djgpp (fwd)
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On Tue, 1 May 2001, The Owl wrote:

> 1. the dpmi app issues a real mode (v86) int 2f/1687 to learn about the
>    dpmi mode switch entry point. the interrupt is serviced by dosx in its
>    RMINT2FHANDLER function (it has been set as the int 2f handler during
>    dosx initialization). the mode switch routine is inside dosx and is
>    called DPMI_CLIENT_PMODE_ENTRY.
> 
> 2. the dpmi app calls DPMI_CLIENT_PMODE_ENTRY to enter protected mode.
>    this function first issues a real mode int 21/62 to get the current
>    real mode PSP segment, then switches to pmode by using ntvdm's Bop
>    interface. once in pmode, dosx allocates various selectors, one of
>    them will be the PSP alias selector. then dosx notifies ntvdm about
>    the startup of a new dpmi app. ntvdm executes _DpmiInitApp AT 0 which
>    will set _CurrentPSPSelector (among other things).

Thanks, I think I understand now.

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