Use this system macro to return the real address of the next prefix
page.
Format
- REG=Rx
- Register that contains the real or absolute address of a prefix
page. R0 cannot be used.
Entry Requirements
- The caller must be in 31-bit mode.
- The caller must be executing in a virtual address space; that is, the
dynamic address translation hardware (DAT) must be activated.
Return Conditions
- Control is returned to the next sequential instruction (NSI).
- The contents of specified register will contain the real address of the
next prefix page. The contents of all other registers are preserved
across this macro call.
Programming Considerations
- All the prefix pages may be visited using the following procedure:
- Load the REG specified register with X'00's indicating the real
address of the I-stream prefix page.
- Call NXTPC to return a new prefix page address.
- Perform whatever prefix page operations are required.
- Repeat the calls to NXTPC using the prefix page addresses returned, until
NXTPC returns X'00's. This condition indicates that the
I-stream prefix page has been looped back to with all prefix pages
visited.
- This macro may be processed on any I-stream.
- This macro is for use in the control program (CP) only.
Examples
None.