unit DriverIOCtl;

interface

uses Windows, Classes, SysUtils;

procedure WritePortB(Port: DWord; Value: byte);

function ReadPortB(Port: DWord): byte;



implementation

const
  GPD_TYPE = 40000;
  METHOD_BUFFERED = 0;
  FILE_READ_ACCESS = 1;
  FILE_WRITE_ACCESS = 2;

var HMassSpFileDevice: THandle;

function CTL_CODE(ADeviceType, AFunction, AMethod, AAccess:DWord ):DWord;
begin
Result := (ADeviceType shl 16) or (AAccess shl 14) or (AFunction shl 2) or AMethod;
end;


{Writes one byte to absolute I/O port.}
procedure WritePortB(Port: DWord; Value: byte);
type WriteBufferB = record
        Port: DWord;
        Data: byte;
        end;
var buf: WriteBufferB;
    ret: Cardinal;
begin
buf.Port := Port;
buf.Data := Value;
if (not DeviceIOControl(HMassSpFileDevice, CTL_CODE(GPD_TYPE, $910, METHOD_BUFFERED, FILE_WRITE_ACCESS), @buf, 5, nil, 0, ret, nil)) or (ret <> 0)
        then raise Exception.Create('Cannot write to device');
end;



{Reads one byte from absolute I/O port.}
function ReadPortB(Port: DWord): byte;
var tmpport: DWord;
    ret: Cardinal;
begin
tmpport := Port;
if (not DeviceIOControl(HMassSpFileDevice, CTL_CODE(GPD_TYPE, $900, METHOD_BUFFERED, FILE_READ_ACCESS), @tmpport, 4, @Result, 1, ret, nil)) or (ret <> 1)
        then raise Exception.Create('Cannot read from device');
end;


initialization
{Get handle of file object created by kernel mode driver}
begin
HMassSpFileDevice := CreateFile('\\.\PortIODev', GENERIC_READ or GENERIC_WRITE, FILE_SHARE_READ, nil, OPEN_EXISTING, 0, 0);
if HMassSpFileDevice = INVALID_HANDLE_VALUE
    then raise Exception.Create('Cannot open device driver');
end;



finalization
{Release handle}
begin
CloseHandle(HMassSpFileDevice);
end;

end.