Component trace passes information to the start/stop exit routine in a parameter list and in GPRs.
Registers at entry: On entry to the start/stop routine, the GPRs and access registers (ARs) contain the following information:
| Register | Contents |
|---|---|
| GPR 0 | No applicable information |
| GPR 1 | Address of the standard parameter list, which contains the address of the component trace parameter list (CTSS). |
| GPRs 2 - 12 | If you use these registers, you must save and restore the contents. |
| GPR 13 | Address of a 72-byte register save area, located in pageable, private-area storage. |
| GPR 14 | Return address. |
| GPR 15 | Entry point address of the start/stop routine. |
| ARs 0 - 15 | If you use these registers, you must save and restore the contents. |
- A table containing the options from an operator REPLY or parmlib member (CTSSOPTP)
- A table containing the ASIDs from an operator REPLY or parmlib member (CTSSASIP)
- A table containing the JOBNAMEs from an operator REPLY or parmlib member (CTSSJOBP)
- A sublevel table (CTSSSNTP) if sublevels are involved in the request.
The CTSSUSRD field of CTSS contains the 16 bytes of information specified on the USERDATA parameter of CTRACE DEFINE. This field will contain zeros if not specified on CTRACE DEFINE. This CTSS user data is treated as input to and output from the start/stop routine, and can be changed by the start/stop routine.
The standard parameter list, the CTSS, the OPTIONS buffer, the ASID table, and the JOBNAME table are located in pageable, private-area storage. The CTSS is mapped by the ITTCTSS mapping macro. For the field descriptions provided by the ITTCTSS mapping macro, see CTSS in z/OS MVS Data Areas in the z/OS Internet library.