gtpi1m1q | System Installation Support Reference |
User exit routine UCCPER2 is invoked whenever a PER event matches the
address ranges and event types specified in the IDSPER control area (for
systemwide tools) or the entry control block (ECB) PER work area (for
ECB-related tools) and the exit point named PER2 is active.
Exit point PER2 is contained in copy segment CPER of CSECT CCCPSE.
The PER debugging tools exit point allows you to process the PER interrupt
with one or more user-developed debugging tools. These tools will see
the interrupt after ZSPER command support (if active), but before the TPF
Assembler Debugger for VisualAge Client.
General Conditions at Entry
The registers at entry to UCCPER2 are:
- R1
- Previous pointer on the PER interrupt handler stack.
- R3
- Address of the PER control area. The IDSPER macro can be used to
map the structure of the control block.
- R6
- Address of the storage area containing the PER interrupt data. The
IDSPER macro can be used to map the structure of the data block.
- R11-R15
- See User Exit Routines - Common Entry Conditions.
System Conditions at Entry
- System state
- Supervisor
- System mask
- Masked
- Protect key
- 0
- Address Space
- SVM or EVM.
Programming Considerations at Entry
- A PER interrupt can occur in either the SVM or the EVM.
- Register 9 (R9) may not contain a valid ECB address in the SVM.
- The PER hardware interface locations are unchanged.
- If the user tools processing this PER interrupt are non-interactive
display or recording tasks, return should be made to CPER so the TPF Assembler
Debugger for VisualAge Client (if it is active) can also handle the PER
interrupt.
- If the user tools processing this PER interrupt are interactive, return
will not be made to CPER and the interrupt will not be visible to the TPF
Assembler Debugger for VisualAge Client. For this condition, correct
functioning of the TPF Assembler Debugger for VisualAge Client may not be
possible.
- If it does not return control to CPER, the user exit must clean up the
stack frame that was being used by the PER interrupt handler when the exit was
invoked. (On entry, R1 contained the previous stack pointer to be
stored into PFXPSAVE to complete stack cleanup.)
- See User Exit Routines - Common Programming Considerations for other considerations.
Programming Considerations on Return
See User Exit Routines - Common Return Conditions.
General Conditions on Return
See User Exit Routines - Common Return Conditions.