Date: Sun, 17 May 1998 14:04:42 +0300 (IDT)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Joseph Kaplan <kaplan AT hokie DOT larc DOT nasa DOT gov>
cc: djgpp AT delorie DOT com
Subject: Re: hardware interrupts
In-Reply-To: <kaplan-1405981731120001@hokie.larc.nasa.gov>
Message-ID: <Pine.SUN.3.91.980517140418.14173J-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
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On Thu, 14 May 1998, Joseph Kaplan wrote:

>   _go32_dpmi_chain_protected_mode_interrupt_vector(
>     interrupt_vector,
>     &protected_receive_handler);

Why do you need to chain?  Is there any other handler for this board
anywhere on your machine?

>   _go32_dpmi_get_real_mode_interrupt_vector(
>     interrupt_vector,
>     &real_previous_handler);

Why do you need to install a real-mode handler?  In DPMI mode, all the
hardware interrupts are automatically reflected to the protected-mode
handler, so you don't need the real-mode one.

> This is not working.

``Not working''--how?  Please explain what happens when your program
runs.

> What am I missing here?

First, your code only installs the handler, but you didn't show the
handler itself.  It might be that the problem is there.

Second, the code and data of the handler need to be locked.

Last but not least, I suggest to read section 18.9 of the DJGPP FAQ
list, if you haven't done that already.