Date:	Tue, 18 Jul 2000 07:48:16 +0200 (DFT)
From:	Szopko Szilard <szopko AT me DOT akki DOT hu>
To:	djgpp AT delorie DOT com
Subject:	TSR program containing interrupt handler in DPMI.
Message-ID:	<Pine.A41.4.05.10007180744410.12678-100000@me.akki.hu>
MIME-Version:	1.0
Reply-To:	djgpp AT delorie DOT com

Dear Colleagues!


My name is Szilard Szopko. I'm working at the Research Institute of
Applied Chemistry in Miskolc in Hungary. I have to program hardware and I
have a problem which I haven't been able to solve yet.

I'm working on a CAN-PCI331 type CAN-BUS interface card. I have to fit
this device to a program written in TURBO PASCAL under MS-DOS operating
system. The install disk of the card contains only a driver written in
GNUC. I have tried to include the routines of the driver into PASCAL, but
it seems, it's not possible. So I have thought, I write a TSR program
using the functions of the driver. This program is an interface beetwen
the card and the PASCAL program. The PASCAL program and the interface
program communicate through any kind of reserved memory area. The
interface program has an interrupt handler routine chained to the 1Ch
interrupt handler. This routine examine the status of the memory area used
in the communication, and call the functions of the driver, if it's
suitable.

The functions of the driver use DPMI so I have to write the interrupt
handler and the hole program in DJGPP. I know, how to write an interrupt
handler and a TSR program in real mode, but I have never wrote them in
protected mode. The writing of a interrupt handler is not a problem, the
DJGPP offers well used routines for this purpose. The making of a TSR
program seems more difficult. I have found two functions called
__dpmi_terminate_and_stay_resident and
__dpmi_install_resident_service_provider_callback. When I wanted to take
resident a program in real mode I had to call the keep function at the end
of the program. It seems the first function is similar to the keep
function in its operation, but if I would like to use this routine I have
to call the second function before. The second routine has a
__dpmi_callback_info type parameter. I don't know how to fill its fields,
and I haven't found document explains this to me. I don't want to try.

So I have the following questions:

How shall I write a TSR program in protected mode?
How shall I use the __dpmi_terminate_and_stay_resident and
__dpmi_install_resident_service_provider_callback functions?
What does the argument of the two functions mean exactly?
How does the fields of the __dpmi_callback_info structure mean exactly and
how shall I fill it to take a program TSR?
Whould you send me some small sample program?

Would You help me? It will be very important and urgent!
My E-mail address: szopko AT me DOT akki DOT hu


								Best Regards!

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