The NMI return pointer register (NRP) contains the return pointer that directs the CPU to the proper location to continue program execution after NMI processing. A branch using the address in NRP (BNRP) in your interrupt service routine returns to the program flow when NMI servicing is complete. The NRP is shown in Figure 8-36 and described in Table 8-320.
Figure 8-36 NMI Return Pointer Register (NRP) LEGEND: R = Readable by the MVC instruction; W = Writeable by the MVC instruction; -x = value is indeterminate after reset |
Table 8-320 NMI Return Pointer Register (NRP) Field DescriptionsBit | Field | Value | Description |
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31 | Reserved | 0 | Reserved. The reserved bit location is always read as 0. A value written to this field has no effect. |
30-0 | Return Address | 0-7FFF FFFFh | Contains the return address. It is written by the CPU while taking an NMI. It is read by the CPU to execute the BNRP instruction. |