Date: Tue, 27 Feb 1996 08:50:27 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: James Tsillas <jtsilla AT ccs DOT neu DOT edu>
Cc: djgpp AT delorie DOT com
Subject: Re: Please help me chain keyboard ISR
In-Reply-To: <JTSILLA.96Feb25222633@atlas.ccs.neu.edu>
Message-Id: <Pine.SUN.3.91.960227084655.8780F-100000@is>
Mime-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On 26 Feb 1996, James Tsillas wrote:

> Question: is this the best way to do this? I guess I don't really
> understand how interrupts are reflected in protected mode. Are the real
> mode handlers bypassed? It seems that the chain is working since the

Under DPMI, hardware interrupts are always passed to protected-mode first 
(after a mode switch, if the interrupt happened when the CPU was in real 
mode, like during a DOS call), and only if unhandled, are they passed to 
real mode.  This is explained in the DJGPP FAQ list (faq200b.zip from the 
same place you get DJGPP), section 18.9.