
{  PURPOSE:
{    This procedure builds a stack frame save area at the beginning of a stack in front of
{    the ring crossing frame.
{
{  NOTE:
{    The design of this procedure is to make it look like pmp$call_ring_crossing_proc called
{    the owner of the ring crossing frame.  When the owner of the ring_crossing frame returns
{    pmp$call_ring_crossing_proc will execute and call pmp$ring_crossing_procedure.
{
{              PMP$BUILD_RING_CROSSING_FRAME (RING_CROSSING_SFSA)
{
{    RING_CROSSING_SFSA: (input) This parameter specifies the address (pva) of the stack frame
{              save area in the stack segment whose previous save area pointer points to a
{              stack frame save area in a stack segment for a higher ring.
{
