gtpi1m1pSystem Installation Support Reference

Program Event Recording (PER)

User exit routine UCCPER is invoked whenever a PER program interrupt is taken that matches the address range and event type requested for display by the ZSPER command and the exit point named PER is active. Exit point PER is contained in copy segment CPER of CSECT CCCPSE.

The PER exit point allows you to interrupt data and expand the amount of data captured by the PER interrupt. The PER user exit logic issues a SNAPC (with return) to write the PER data to tape. When the PER user exit is not active, PER processing issues the SNAPC for the common set of data.

General Conditions at Entry

The registers at entry to UCCPER are:

R1
Address of a 1-byte return flag used to show whether the PER interrupt data should be processed or discarded by the ZSPER command.

R3
Address of the PER control area. The IDSPER macro can be used to DSECT the control block.

R6
Address of the storage block containing the PER interrupt data. The IDSPER macro can be used to DSECT 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.

Programming Considerations at Entry

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

  1. To bypass additional processing of PER interrupt data by the ZSPER command, set bit 0 of the byte at the address in R1 to 1 (X'80'). To continue processing the PER interrupt data, no change is required. Regardless of the flag setting returned by this exit, the PER interrupt may still be eligible for processing by the PER debugging tools exit point (UCCPER2) or the TPF Assembler Debugger for VisualAge Client.
  2. See User Exit Routines - Common Return Conditions.