VXB_RESOURCE * AIO_pRes;
unsigned AIO_IRQ;
unsigned AIO_ADDR;
?? AIO_IVEC;

DEV_HDR * pHdr;


STATUS AIO_OpenDevice( void * reserved_parameters ){
  int busno, devno, funcno;

    /* Locate the device on the PCI bus */
    if (pciFindDevice (0x494F, 0x0100, 0, &busno, &devno, &funcno) == OK) // might be kernel only
    {
        // Device found
        // acquire address of important register block at BAR[2]
        pciConfigInLong (busno, devno, funcno, PCI_CFG_BASE_ADDRESS_2, &AIO_ADDR );
        AIO_ADDR &= 0xFFFC; // clear out I/O bits etc

        // acquire IRQ# from PCI Config registers
        pciConfigInByte (busno, devno, funcno, PCI_CFG_DEV_INT_LINE, &AIO_IRQ );

        // convert PCI IRQ# to Interrupt Vector ID needed by intConnect()
        AIO_IVEC = INUM_TO_IVEC (sysInumTbl[(int)AIO_IRQ]);
    }
    else
        return (ERROR);


    pciConfigInByte( bus, devno, funcno, 0x18, &AIO_ADDR ); // 0x18 == BAR2

    if ((AIO_ADDR <= 0x0100) || (AIO_ADDR == 0xFFFC))
    {
        AIO_ADDR = 0;
        return ERROR;
    }
}

STATUS AIO_IRQ_Handler((void *)() customerIRQhandler){
  return intConnect (AIO_IVEC, customerIRQhandler, 0);
}

void AIO_DIO_Configure(bool A, B, CHi, CLo){
  return sysOutByte(AIO_ADDR+3, (A?0:0x10) | (B?0:0x02) | (CHi?0:0x08) | (CLo?0:0x01) | 0x80 ); // "0" is output per port bit, "0x80" is "set mode", all other bits are left "0" for "82C55 Mode 0" compatibility
}

void AIO_DIO_WriteAll(UInt32 Data){
    if (AIO_ADDR)
        sysOutLong (AIO_ADDR, Data & 0x00FFFFFF); // write to port A B C, don't write "D31 set" to +3 or it would issue a Mode command...
}

UInt32 AIO_DIO_ReadAll(void){
    if (AIO_ADDR)
        return sysInLong(AIO_ADDR) & 0x00FFFFFF;  // read ports A B C, don't readback the mode byte
}

byte AIO_IRQ_Status(){
    if (AIO_ADDR)
        return sysInByte(AIO_ADDR+0x29, 0xFF) & 0x01; // "1" means an IRQ is latched
}

void AIO_IRQ_Enable(){
    if (AIO_ADDR)
        sysOutByte(AIO_ADDR+0x28, 0xFF);
}

void AIO_IRQ_Clear(){
    if (AIO_ADDR)
        sysOutByte(AIO_ADDR+0x29, 0xFF);
}

void AIO_IRQ_Disable(){
    if (AIO_ADDR)
        sysOutByte(AIO_ADDR+0x29, 0xFF);
}

void AIO_CloseDevice(){
    AIO_ADDR = 0;
}




void main(void) // test routine / sample program
{
    if (OpenDevice() == SUCCESS)
    {
        DIO_Configure(OUTPUT, OUTPUT, INPUT, OUTPUT); // port A, B, CHi, CLo direction control
        DIO_WriteAll(0x012345L); // write 24 bits of output; bits for CHi ("4"), will be ignored as it is an input
        UInt32 DIO_Data = DIO_ReadAll(); // read 24 bits of input; reads from outputs provide stored register value ("readback")

        IRQ_Handler(myISR);
        IRQ_Clear();
        IRQ_Enable();

        ... handle IRQ stuff ...

        CloseDevice();
    }
}