Port IO problem

[Aisin Geuru Suen Yue]

Windows NT was designed so that (theoretically) no application could crash the operating system. Part of that security model is that NT will not allow any user-mode (Ring 3) application to access hardware ports. For this reason, INP and OUT was removed from the PowerBASIC language in PB/DLL 32-bit and PB/CC.
However, Windows 95/98 is not a true 32-bit operating system and does not support the NT security model. So technically, an application *can* directly access a hardware port (although we highly recommend that you NOT do it). To do so, you simply use the "in" and "out" assembler instructions.
The following code encapsulates this for those of you not familiar with assembler:

SUB pbOut(BYVAL port AS INTEGER, BYVAL value AS INTEGER)
! mov AX, value
! mov DX, port
! out DX, AL
END SUB

FUNCTION pbInp(BYVAL port AS INTEGER) AS INTEGER
! mov DX, port
! in AL, DX
! mov FUNCTION[0], AL
END FUNCTION

I have read this message and try to use the function,
everything fine when compiling, but when I run it
the windows illegal operation window come-up, I am
using Windows 98 SE.
What's wrong, anybody can help.

[Lance Edmonds]

It is unlikely anyone is going to be able to suggest a solution, because you have not posted enough information on the problem.

If you single-step your program in the debugger, where *exactly* does the Illegal Operation occur? In otherwords, how do we know that it is occuring within these functions? (ie, you may have a problems elsewhere in your code that is causing this problem).

What port(s) are you trying to access? Does this code fail on the 1st attempt, or do they work for a while?

What exactly does your program do?

Also, which version of PB/DLL are you using?

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Aisin Geuru Suen Yue]

I am using Pbdll6 on P3-500 machine with Windows 98 Second edition OS, below are the source code for my control program,
using ISA bus, port address 608(Decimal),this program was transfer from VB6(working!) and modify to suit PBDll6, it compile,but have run time trouble with illegal call.

'================================================================
'Motion control by 8255
'
'
'================================================================
' Set ID for all the dialog control items

#COMPILE EXE
#INCLUDE "Win32Api.Inc"

%IDMOVE_X_MINUS          = 1
%IDMOVE_X_PLUS           = 2
%IDEXIT                  = 3
%BS_DEFAULT              = 1      'Set the button appearance

'------------------------------------------------------------
' Global variable to recieve the user input and variable

GLOBAL PORTBASE AS INTEGER
                                                  
'-------------------------------------------------------------
'Routine for outport data to port

SUB pbOut(BYVAL oport AS INTEGER, BYVAL value AS INTEGER)
  '! mov DX, oport
  '! mov AL, value
  '! out DX, AL

  ! mov AX, value
  ! mov DX, oport
  ! out DX, AL
END SUB

'------------------------------------------------------------
'Routine for replace doevents in VB
SUB DOEVENT() EXPORT
   STATIC Msg AS tagMsg
   IF PeekMessage(Msg, %NULL, 0, 0, %PM_REMOVE) THEN
      TranslateMessage Msg
      DispatchMessage Msg
      END IF
      END SUB
'----------------------------------------------------------------
'Routine for delay timing
SUB Delay(DelayInMilliseconds AS SINGLE)
DIM tmout AS SINGLE
tmout = DelayInMilliseconds + timeGetTime()
DO UNTIL timeGetTime() >= tmout
CALL DOEVENT
LOOP
END SUB

'----------------------------------------------------------------
'Routine for Pulsing the X-Axis motor in clockwise direction
SUB Move_X_minu(STEPP AS SINGLE)

DIM X AS INTEGER
    FOR X = 1 TO STEPP

    CALL pbOut(PORTBASE+1,3)           'turn on portB bit 2

    'now bring control port bit 2 to high and low
    'to latch the data to it's output.

    CALL pbOut(PORTBASE+2,2)
    CALL pbOut(PORTBASE+2,0)

        Delay(1)                   'off time if current sinking

           CALL pbOut(PORTBASE+1,2)      'turn off portB bit 2


           CALL pbOut(PORTBASE+2,2)       'but keep bit 1 low
           CALL pbOut(PORTBASE+2,0)

        Delay (1)                 'on time if current sinking

NEXT X
END SUB
'--------------------------------------------------------------
'Routine for pulsing the x-axis motor anti-clockwise
SUB Move_X_PLUS(STEPP AS SINGLE)

DIM X AS INTEGER

    FOR X = 1 TO STEPP

    CALL    pbOut(PORTBASE+1,3)        'turn on portB bit 2

    'now bring control port bit 2 to high and low
    'to latch the data to it's output.

    CALL pbOut(PORTBASE+2,2)
    CALL pbOut(PORTBASE+2,0)

        Delay(1)               'off time if current sinking

            CALL pbOut(PORTBASE+1,1)     'turn off portB bit 2
            CALL pbOut(PORTBASE+2,2)     'but keep bit 1 low
            CALL pbOut(PORTBASE+2,0)

        Delay (1)                 'on time if current sinking

NEXT X
END SUB

'----------------------------------------------------------------
CALLBACK FUNCTION MoveXminus()

Move_X_minu (200)

END FUNCTION

'--------------------------------------------------------
CALLBACK FUNCTION MoveXplus()

Move_X_plus (200)

END FUNCTION

'--------------------------------------------------------
CALLBACK FUNCTION Exit_prog()

  DIALOG END CBHNDL, 0

END FUNCTION

'--------------------------------------------------------------

FUNCTION PBMAIN () AS LONG

  $REGISTER NONE

  LOCAL hDlg   AS LONG

' ** Create a new dialog template
  DIALOG NEW 0, "Motion of X-Y Table", ,, 300, 200, 0, 0 TO hDlg

' ** Add controls to it
'-------------------------------------------------------------
CONTROL ADD BUTTON, _
hDlg, _
%IDMOVE_X_MINUS, _
"MOVE X-", _
100, _
10, _
50, _
12, _
CALL MOVE_X_MINU

'--------------------------------------------------------------
CONTROL ADD BUTTON, _
hDlg, _
%IDMOVE_X_PLUS, _
"MOVE X+", _
100, _
30, _
50, _
12, _
CALL MOVE_X_PLUS

'--------------------------------------------------------------

CONTROL ADD BUTTON, hDlg, %IDEXIT, "Exit", _
110, 75, 40, 14, 0 CALL exit_prog

'------------------------------------------------------------
    
    PORTBASE=608                      'address IN ISA bus
    CALL pbOut(PORTBASE+3,128)
'8255 control word,send data 128 to port 611 
'for set all port are output

                                        
' ** Display the dialog
  DIALOG SHOW MODAL hDlg


END FUNCTION

[John Hutchins]

I have had no problems with 95/98 with the following:
'------------------------------------------------------------------------------------------------
' TITLE: Out32
' DESC: Writes data (ByteValue)to I/O port (PortAddress).
' SYNTAX: Out32 PortAddress, ByteValue
' NOTES: This procedure is for use with I/O ports using 8 bit data ie. ISA expansion cards.
' This procedure may also be used to write data to SPP mode parallel ports

DECLARE SUB Out32(BYVAL PortAddress AS INTEGER,BYVAL ByteValue AS BYTE)

SUB Out32(BYVAL PortAddress AS INTEGER,BYVAL ByteValue AS BYTE)

! push dx
! mov dx,PortAddress
! mov al,ByteValue
! out dx,al
! pop dx

END SUB


'------------------------------------------------------------------------------------------------
' TITLE: In32
' DESC: Returns data from I/O port (PortAddress).
' SYNTAX: In32 PortAddress TO Variable?
' NOTES: This procedure is for use with I/O ports using 8 bit data ie. ISA expansion cards.
' This procedure may also be used to return the last data written to a SPP mode parallel
' port. It will NOT work with EPP mode parallel ports.


DECLARE FUNCTION In32(BYVAL PortAddress AS INTEGER) AS BYTE

FUNCTION In32(BYVAL PortAddress AS INTEGER) AS BYTE
LOCAL ByteValue AS BYTE

! push dx
! mov dx,PortAddress
! in al,dx
! mov ByteValue,al
! pop dx

FUNCTION = ByteValue
END FUNCTION

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