Register contents when Exit 16 passes control back to JES2

Upon return from this exit, the register contents must be:

A return code of:

0: Tells JES2 that if any additional exit routines are associated with this exit, call the next consecutive exit routine. If there are no additional exit routines associated with exit continue normal notify processing.
4: Tells JES2 to ignore any other exit routines associated with this exit and to continue normal notify processing.
8: Tells JES2 not to issue the notify $WTO.