port95.pas

《Delphi7编程100例》代码,书配资料

{********************************************************}
{                     unit Port95                        }
{                                                        }
{ Access to the I/O ports under Win95/98 in Pascal-style }
{                                                        }
{         Copyright (c) 1997,1998 Vlad Sharnin           }
{                                                        }
{             E-mail: [e-mail]                 }
{          Home page: http://vladshar.ufanet.ru          }
{                                                        }
{********************************************************}
unit Port95;

interface

type
  TPort = class
    procedure SetPort(Index: Word; Value: Byte);
    function GetPort(Index: Word): Byte;
    property Port[Index: Word]: Byte read GetPort write SetPort; default;
  end;

  TPortW = class
    procedure SetPortW(Index: Word; Value: Word);
    function GetPortW(Index: Word): Word;
    property PortW[Index: Word]: Word read GetPortW write SetPortW; default;
  end;

var
  Port: TPort;
  PortW: TPortW;

implementation

procedure TPort.SetPort(Index: Word; Value: Byte); assembler; register;
asm
  mov  al,cl
  out  dx,al
end;

function TPort.GetPort(Index: Word): Byte; assembler; register;
asm
  in  al,dx
end;

procedure TPortW.SetPortW(Index: Word; Value: Word); assembler; register;
asm
  mov  ax,cx
  out  dx,ax
end;

function TPortW.GetPortW(Index: Word): Word; assembler; register;
asm
  in  ax,dx
end;

initialization
  Port := TPort.Create;
  PortW := TPortW.Create;
finalization
  Port.Free;
  PortW.Free;
end.