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6.15.12 BP compatibility (partly): Port, PortW arrays

The following listing contains the interface of the Ports unit.

This unit provides access routines for the hardware ports on the IA32, as a partial replacement for BP's Port and PortW pseudo arrays.

Since port access is platform-specific, this unit cannot be used in code intended to be portable. Even on the IA32, its use can often be avoided – e.g. Linux provides a number of ioctl functions, and DJGPP provides some routines to achieve things that would require port access under BP. Therefore, it is recommended to avoid using this unit whenever possible.

     { Access functions for I/O ports for GPC on an IA32 platform. This
       unit is *not* portable. It works only on IA32 platforms (tested
       under Linux and DJGPP). It is provided here only to serve as a
       replacement for BP's Port and PortW pseudo arrays.
     
       Copyright (C) 1998-2005 Free Software Foundation, Inc.
     
       Author: Frank Heckenbach <frank@pascal.gnu.de>
     
       This file is part of GNU Pascal.
     
       GNU Pascal is free software; you can redistribute it and/or modify
       it under the terms of the GNU General Public License as published
       by the Free Software Foundation; either version 2, or (at your
       option) any later version.
     
       GNU Pascal is distributed in the hope that it will be useful, but
       WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
       General Public License for more details.
     
       You should have received a copy of the GNU General Public License
       along with GNU Pascal; see the file COPYING. If not, write to the
       Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
       02111-1307, USA.
     
       As a special exception, if you link this file with files compiled
       with a GNU compiler to produce an executable, this does not cause
       the resulting executable to be covered by the GNU General Public
       License. This exception does not however invalidate any other
       reasons why the executable file might be covered by the GNU
       General Public License. }
     
     {$gnu-pascal,I-}
     {$if __GPC_RELEASE__ < 20030303}
     {$error This unit requires GPC release 20030303 or newer.}
     {$endif}
     {$ifndef __i386__}
     {$error The Ports unit is only for the IA32 platform}
     {$endif}
     
     unit Ports;
     
     interface
     
     { Port access functions }
     function  InPortB  (PortNumber: ShortWord): Byte;
     function  InPortW  (PortNumber: ShortWord): ShortWord;
     procedure OutPortB (PortNumber: ShortWord; aValue: Byte);
     procedure OutPortW (PortNumber, aValue: ShortWord);
     
     { libc functions for getting access to the ports -- only for root
       processes, of course -- and to give up root privileges after
       getting access to the ports for setuid root programs. Dummies
       under DJGPP. }
     {$ifdef MSDOS}
     function  IOPerm (From, Num: MedCard; On: Integer): Integer;
       attribute (name = 'ioperm');
     function  IOPL (Level: Integer): Integer; attribute (name = 'iopl');
     function  SetEUID (EUID: Integer): Integer; attribute (name
       = 'seteuid');
     {$else}
     function  IOPerm (From, Num: MedCard; On: Integer): Integer;
       external name 'ioperm';
     function  IOPL (Level: Integer): Integer; external name 'iopl';
     function  SetEUID (EUID: Integer): Integer; external name 'seteuid';
     {$endif}