{
Access functions for I/O ports for GPC on an x86 platform. This unit
is *not* portable. It works only on x86 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) 1998-2000 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.
}

{$gnu-pascal}
{$ifndef __i386__}
{$error The Ports unit is only for the x86 platform}
{$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. }
function  IOPerm (From, Num : MedCard; On : Integer) : Integer; asmname 'ioperm';
function  IOPL (Level : Integer) : Integer;                     asmname 'iopl';
function  SetEUID (EUID : Integer) : Integer;                   asmname 'seteuid';

implementation

function InPortB (PortNumber : ShortWord) : Byte;
var aValue : volatile Byte; (*@@*)
begin
  asm ('inb %%dx, %%al' : '=a' (aValue) : 'd' (PortNumber));
  InPortB := aValue
end;

function InPortW (PortNumber : ShortWord) : ShortWord;
var aValue : volatile ShortWord; (*@@*)
begin
  asm ('inw %%dx, %%ax' : '=a' (aValue) : 'd' (PortNumber));
  InPortW := aValue
end;

procedure OutPortB (PortNumber : ShortWord; aValue : Byte);
begin
  asm ('outb %%al, %%dx' : : 'd' (PortNumber), 'a' (aValue))
end;

procedure OutPortW (PortNumber, aValue : ShortWord);
begin
  asm ('outw %%ax, %%dx' : : 'd' (PortNumber), 'a' (aValue))
end;

{$ifdef MSDOS}

function IOPerm (From, Num : MedCard; On : Integer) : Integer;
var Dummy : Integer;
begin
  Dummy := From;
  Dummy := Num;
  Dummy := On;
  IOPerm := 0
end;

function IOPL (Level : Integer) : Integer;
var Dummy : Integer;
begin
  Dummy := Level;
  IOPL := 0
end;

function SetEUID (EUID : Integer) : Integer;
var Dummy : Integer;
begin
  Dummy := EUID;
  SetEUID := 0
end;

{$endif}

end.
