SCO OpenServer

flushtlb(D3oddi)

flushtlb -- flush the translation lookaside buffer

Synopsis

void flushtlb();

Description

flushtbl( ) is used to flush the Translation Lookahead Buffer (TLA) for older hardware.

Arguments

None.

Return values

None.

Usage

The flushtlb( ) function is supplied for users of very early versions of 16 and 25 MHz 386 systems using Micro Channel cards, where, when accessing an I/O port above 0x1000, a driver must flush the translate lookaside buffer (TLB). A call to flushtlb( ) prevents corruption of the I/O address. Note that the call to flushtlb( ) must be protected by a call to spl7(D3oddi) to prevent interrupts from occurring while flushtlb is operating.

Context and synchronization

context

Hardware applicability

Very early versions of 16 and 25 MHz 386 systems using Micro Channel cards.

Version applicability

Blockable oddi: 1

Differences between versions

This function is not required for any current hardware. Current drivers can just delete calls to this function.

SVR5 DDI compatibility

This function is not supported for DDI drivers. It is not required for current hardware and so can just be deleted when porting drivers to DDI.

References

inb(D3oddi), spl(D3oddi), spl7(D3oddi)

Examples

The following example is for a driver routine that gets a byte from an I/O port and checks the address before beginning processing. A driver should also have a similar routine for writing data to an I/O port.

   int
   getbyte(port)
   {
       int x, ret;
       /*
        * If port address is less than hex 1000,
        *   get byte and return.
        */
       if (port < 0x1000)      
           return(inb(port));
                           /*           else,       */
       x = spl7();         /* block all interrupts  */
       flushtlb();         /* flush TLB             */
       ret = inb(port);    /* get byte from port    */
       splx(x);            /* reset previous spl    */
       return(ret);        /* return byte to caller */
   }