$LOCKED_PAGE_START is used with $LOCKED_PAGE_END to delineate
    code that may be locked at image initialization time by the
    $LOCK_PAGE_INIT macro. The code delineated by these macros must
    contain complete routines-execution may not fall through either
    macro, nor may the locked code be branched into or out of. Any
    attempt to branch into or out of the locked code section or to
    fall through the macros will be flagged by the compiler with an
    error.