Date:	Sun, 22 Nov 1998 14:36:05 +0200 (IST)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
X-Sender:	eliz AT is
To:	Willy Lee <willy2 AT jps DOT net>
cc:	djgpp AT delorie DOT com
Subject:	Re: TSRs with DJGPP?
In-Reply-To:	<3657E72D.99420240@jps.net>
Message-ID:	<Pine.SUN.3.91.981122142926.17686U-100000@is>
MIME-Version:	1.0
Reply-To:	djgpp AT delorie DOT com

On Sun, 22 Nov 1998, Willy Lee wrote:

> I should explain that I'm trying to hook Int 0x15, function 0x4F, which
> is supposed to be called by the Int 0x09 (keyboard interrupt) handler
> from real-mode. 

Int 15h is a software interrupt, and these are NOT reflected to protected 
mode.  You need to install a real-mode handler.

> What's the best thing for me to do here? Looks like I need to set a
> real-mode vector to point to a real-mode address for my handler. Do I
> need to setup a real-mode callback? Or should I just make the handler 
> completely real-mode?

See the FAQ for the instructions on how to install a real-mode handler.  
If something's unclear there, ask specific questions.  In general, a 
callback should be enough, unless it isn't fast enough for your needs 
(since a callback involves a mode switch).

> If I setup a real-mode callback, can I still chain to the old protected
> mode vector using _go32_dpmi_chain_....? 

No, this function is for chaining to protected-mode interrupts only.  
There is no function in the library for chaining to real-mode interrupts, 
you will need either to modify the register structure passed to your 
real-mode handler, before it returns; or call the previous handler from 
your handler using the _go32_... functions that simulate far procedure 
calls (look them up in the library reference).

- Raw text -