Process Stack (on entry)

As defined in Intel® Itanium ™ Processor-specific Application Binary Interface, section 3.3.5, the return pointer register (rp) shall contain a valid return address, such that if the application program returns from the main entry routine, the implementation shall cause the application to exit normally, using the returned value as the exit status. Further, the unwind information for this "bottom of stack" routine in the implementation shall provide a mechanism for recognizing the bottom of the stack during a stack unwind.