{
{    The purpose of this request is to establish a procedure that will process
{ the specified condition(s) in the specified block.  Condition handlers are
{ stacked in the order they are established.  When a condition arises, the most
{ recently established handler for that condition is given control.
{
{    On block exit all condition handlers established in that block are
{ automatically disestablished.
{
{       PMP$ESTABLISH_CH_IN_BLOCK (CONDITIONS, CONDITION_HANDLER, BLOCK,
{             ESTABLISH_DESCRIPTOR, STATUS)
{
{  CONDITIONS: (input)  This parameter specifies the conditions for which the
{        handler is being established.
{
{  CONDITION_HANDLER: (input)  This parameter specifies the user's condition
{        handler.
{
{  BLOCK: (input)  This parameter specifies the block in which the handler is
{        to be established.
{
{  ESTABLISH_DESCRIPTOR: (input, output)  This parameter specifies the variable
{        that describes the established condition handler.  This variable must
{        in the stack segment specified by block at an address greater than
{        that of block.  The values of this variable are initialized by the
{        request processor and need not be initialized by the requestor.
{        WARNING:  re-use of an establish_descriptor (e.g., two establish
{        requests for the same block which utilize the same descriptor) will
{        cause undefined results.
{
{  STATUS: (output) This parameter specifies the request status.
{       CONDITIONS:
{             pme$invalid_condition_selector
{             pme$incorrect_condition_name
{             pme$descriptor_address_error
{             pme$unselectable_condition
{             pme$handler_stack_error
{             pme$inconsistent_stack
{
