The arguments for the $PROCEDURE_DESCRIPTOR macro are the same as
    the $ROUTINE macro, with the following exceptions:

    o  The ENTRY argument is required.

    o  There are no CODE_SECTION, LINKAGE_SECTION, DATA_SECTION,
       DATA_SECTION_POINTER, or STANDARD_PROLOGUE arguments.

    o  There is an additional END_PROLOGUE argument. This argument
       must be a label that you define at the end of the routine's
       prologue sequence. This argument is required for stack and
       register procedure types.