I got a EXCEPTION_PRIV_INSTRUCTION

Question

Hi there,
I'm trying to control the parallel port using java.
Here's my code(very simple):
import parport.ParallelPort;
public class Principal {
     public static void main(String[] args) {
          ParallelPort lpt1 = new ParallelPort(0x378);
          for(int i=1; i<128; i=i*2){
               lpt1.write(i);
               try {
                    Thread.sleep(500);
               } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
}Here's the code of the ParalellPort:
package parport;
     public class ParallelPort {
        /** The port base address (e.g. 0x378 is base address for LPT1) */
        private int portBase;
        /** To cunstruct a ParallelPort object,
          * you need the port base address
        public ParallelPort (int portBase)
           this.portBase = portBase;
        /** Reads one byte from the STATUS pins of the parallel port.
          * The byte read contains 5 valid bits, corresponing to 5 pins of input
          * from the STATUS pins of the parallel port (the STATUS is located
          * at "portBase + 1", e.g. the STATUS address for LPT1 is 0x379).
          * This diagram shows the content of the byte:
          *  Bit | Pin # | Printer Status  | Inverted
          * -----+-------+-----------------+-----------
          *   7  |  ~11  | Busy            |   Yes
          *   6  |   10  | Acknowledge     |
          *   5  |   12  | Out of paper    |
          *   4  |   13  | Selected        |
          *   3  |   15  | I/O error       |
          * Note that Pin 11 is inverted, this means that "Hi" input on pin
          * means 0 on bit 7, "Low" input on pin means 1 on bit 7.
        public int read ()
           return ParallelPort.readOneByte (this.portBase+1);
        /** Writes one byte to the DATA pins of parallel port.
          * The byte is written to the DATA pins of the port. The DATA pins are
          * located at the base address of the port (e.g. DATA address for LPT1
          * is 0x378).
          * This diagram shows how the byte is written:
          *  Bit | Pin # | Printer DATA
          * -----+-------+--------------
          *   7  |   9   |   DATA 7
          *   6  |   8   |   DATA 6
          *   5  |   7   |   DATA 5
          *   4  |   6   |   DATA 4
          *   3  |   5   |   DATA 3
          *   2  |   4   |   DATA 2
          *   1  |   3   |   DATA 1
          *   0  |   2   |   DATA 0
        public void write (int oneByte)
           ParallelPort.writeOneByte (this.portBase, oneByte);
        /** Reads one byte from the specified address.
          * (normally the address is the STATUS pins of the port)
        public static native int readOneByte (int address);
        /** Writes one byte to the specified address
          * (normally the address is the DATA pins of the port)
        public static native void writeOneByte (int address, int oneByte);
        static
           System.loadLibrary("parport");
     }And here's the message i got when i try to run it:
# An unexpected error has been detected by Java Runtime Environment:
#  EXCEPTION_PRIV_INSTRUCTION (0xc0000096) at pc=0x1000107b, pid=2464, tid=896
# Java VM: Java HotSpot(TM) Client VM (1.6.0_03-b05 mixed mode)
# Problematic frame:
# C  [parport.dll+0x107b]
# An error report file with more information is saved as hs_err_pid2464.log
# If you would like to submit a bug report, please visit:
#   http://java.sun.com/webapps/bugreport/crash.jsp
#Any ideas? I'm using Windows XP Sp2.
In my university i was able to use this algoritm, but there we use Sp1, could be it?
Before someone ask i'm suing UsePort to unlock the Paralell Port.
Thx a lot.

Answer 1

What is the parport native library?
It is not a JVM error, but a parport library error. It tries to execute privilidged instruction (like 'in' or 'out' for intel x86) in user mode, but this instruction should be executed only in kernel mode. You should write proper kernel driver and communicate with it via public OS api, or use some undocumented API to allow you application to use some privilidged instructions like port I/O for specific number of ports (search web for giveio.sys or inpout32.dll, they use second approach).