gtpi1m1qSystem Installation Support Reference

Program Event Recording (PER) Debugging Tools

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

  1. A PER interrupt can occur in either the SVM or the EVM.
  2. Register 9 (R9) may not contain a valid ECB address in the SVM.
  3. The PER hardware interface locations are unchanged.
  4. 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.
  5. 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.
  6. 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.)
  7. 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.