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From: winter@hpmcaa.mcm.hp.com (Kirt Alan Winter)
Newsgroups: comp.os.os2.programmer
Subject: Re: OS/2 device drivers
Message-ID: <1991Apr10.211127.13982@hpmcaa.mcm.hp.com>
Date: 10 Apr 91 21:11:27 GMT
References: <1991Apr09.151935.19325@lut.fi>
Organization: HP Cardiology Business Unit - McMinnville, OR
Lines: 32

cale@lut.fi (Antti Kirmanen) writes:
> 
> I'm currently trying to write a device driver for OS/2.
> My problem is, that I should use inp and outp functions to
> communicate with a port. OS/2 programmers reference manual
> says, that I should use DosPortAccess() function call but then ...
> Program crashes allways in the first outp() or inp() call.
> I'm using Microsoft C 6.0 with OS/2 1.1
> 
> Can anyone help me. A simple example would be great.
> Thanks in advance....

Well, I just faced the same problem (though not inside a device driver),
so I can perhaps shed a little light on the problem.

The routines that do port I/O must execute at the IOPL (sorry if my
OS/2 terminology is a bit sloppy, I'm new at this).  Near as I can tell,
it is useless to put the outp and inp calls in the library, as they will
not work.

I ended up writing my own inp and outp in assembly, so I could declare
them as IOPL in the module definition file.

For a better explanation, refer to Ray Duncan's _Advanced OS/2 Programming_,
chapter 14.

Kirt 
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 Kirt Alan Winter                                    winter@hpmcaa.mcm.hp.com
 Hewlett Packard - Cardiology Business Unit          (503) 472-5101 x371
 McMinnville, Oregon
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