NTSTATUS
KeI386FlatToGdtSelector(
  IN  ULONG SelectorBase,
  IN  USHORT Length,
  IN  USHORT Selector
  );

Routine Description:

    This function converts a 32-bit flat address to a GDT selector-offset
    pair.  The segment set up is always 16-bit ring 0 data segment.

Arguments:

    SelectorBase - Supplies 32 bit flat address to be set as the base address
                   of the desired selector.

    Length - Supplies the Length of the segment.  The Length is a 16 bit value
             and zero means 64KB.

    Selector - Supplies the selector to be set up.

Return Value:

    STATUS_SUCCESS - If the requested LID is released.

    STATUS_ABIOS_NOT_PRESENT - If there is no ABIOS support in the system.

    STATUS_ABIOS_INVALID_SELECTOR - If the selector supplied is invalid.