From: dewar@merv.cs.nyu.edu (Robert Dewar)
Subject: Re: question re Ada equivalent of C function
Date: 1998/02/22
Date: 1998-02-22T00:00:00+00:00 [thread overview]
Message-ID: <dewar.888162643@merv> (raw)
In-Reply-To: 01bd3f7d$43882660$4a2c5c8b@aptiva
<<As both Linux and NT are real operating systems, neither will allow you to
directly
access an IO port from a user program. By messing around with rights and
such
you might be able to pull it off using inline-assembly tricks, but at this
low level
both Linux vs NT and GNAT vs OA are incompatible.
>>
Although this may be a valid description of restrictions in NT and Linux,
it is by no means a necessary restriction. In OS/2, you can use inp and
outp from a protected mode program if you use a .DEF file to declare
the IOSEG segment that the run-time library uses to perform
input/output to the port. The code for the segment must be marked
with the IOPL keyword in the .DEF file. FOr more details, have a look
at the OS/2 documentation, or look in the Microsoft C Run-Time
Library Reference document (an excellent source for all sorts of
information on C-callable routines and their compatibility across
systems).
I am not suggesting that everyone move to OS/2, just pointing out that
the chain of reasoning that X is a "real operating system", therefore
X cannot allow you to directly access an IO port is misleading.
next prev parent reply other threads:[~1998-02-22 0:00 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-02-21 0:00 question re Ada equivalent of C function David Fisher
1998-02-21 0:00 ` Brian Rogoff
1998-02-21 0:00 ` Robert Dewar
1998-02-22 0:00 ` Brian Rogoff
1998-02-21 0:00 ` Jerry van Dijk
1998-02-21 0:00 ` David Fisher
1998-02-22 0:00 ` Jerry van Dijk
1998-02-22 0:00 ` Robert Dewar [this message]
1998-02-22 0:00 ` Andi Kleen
1998-02-22 0:00 ` Simon Wright
1998-02-22 0:00 ` Simon Wright
1998-02-22 0:00 ` Nick Roberts
1998-02-22 0:00 ` frc
1998-02-21 0:00 ` Robert Dewar
1998-02-21 0:00 ` Corey Ashford
1998-02-22 0:00 ` Nick Roberts
1998-02-22 0:00 ` Larry Kilgallen
1998-02-22 0:00 ` Robert Dewar
1998-02-22 0:00 ` frc
1998-02-22 0:00 ` Linux/POSIX packages for GNAT Markus Kuhn
1998-02-22 0:00 ` Robert Dewar
1998-02-23 0:00 ` Markus Kuhn
1998-02-23 0:00 ` Robert Dewar
1998-02-23 0:00 ` Markus Kuhn
1998-02-24 0:00 ` question re Ada equivalent of C function Dale Stanbrough
1998-02-23 0:00 ` Linux/POSIX packages for GNAT Andi Kleen
1998-02-22 0:00 ` Robert Dewar
1998-02-23 0:00 ` Markus Kuhn
1998-02-23 0:00 ` Robert Dewar
1998-02-22 0:00 ` Andi Kleen
1998-02-22 0:00 ` Markus Kuhn
1998-02-22 0:00 ` Robert Dewar
1998-02-22 0:00 ` Samuel Tardieu
1998-02-23 0:00 ` Nick Roberts
1998-02-23 0:00 ` Samuel Tardieu
1998-03-05 0:00 ` Testing exception handlers James M. Darlack
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