EZBCTAPI NMI output register information

When control returns to the caller, the general purpose registers (GPRs) contain:

Register contents
0	Reason code, if GPR 15 contains a nonzero return code; otherwise, used as a work register by the system
1	Used as a work register by the system
2 - 13	Unchanged
14	Used as a work register by the system
15	Return code

When control returns to the caller, the access registers (ARs) contain:

Register contents
0 - 1	Used as work registers by the system
2 - 13	Unchanged
14 - 15	Used as a work register by the system

Some callers depend on register contents remaining the same before and after issuing a service. If the system changes the contents of registers on which the caller depends, the caller must save them before issuing the service, and restore them after the system returns control.