Date: Mon, 13 Oct 1997 15:18:57 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: "Gurunandan R. Bhat" <grbhat AT unigoa DOT ernet DOT in>
cc: Leath Muller <leathm AT solwarra DOT gbrmpa DOT gov DOT au>,
        firewind <firewind AT metroid DOT dyn DOT ml DOT org>, djgpp AT delorie DOT com
Subject: Re: DJGPP+Allegro: Porting from DOS to Linux. Easy or Hard!?!
In-Reply-To: <Pine.LNX.3.91.971012084325.273C-100000@aditya.unigoa.ernet.in>
Message-ID: <Pine.SUN.3.91.971013151823.11407W-100000@is>
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On Sun, 12 Oct 1997, Gurunandan R. Bhat wrote:

> Isn't it the _stub_ that does the rm -> pm switch. I always thought that 
> the DPMI host makes DPMI services available via INT 31H in much the way 
> that DOS makes DOS services available via INT 21H.

It's both, actually.  The DPMI host provides a function to switch the
CPU into protected mode.  The stub *calls* this function to do the
switch.  The DPMI host then actually switches the CPU into PM by using
whatever low-level support it has available (VCPI, XMS, etc.) from
installed memory manager (EMM386, QEMM, HIMEM...).