gtpi1m0sSystem Installation Support Reference

Control Transfer

User exit routine UCCCMXF is invoked whenever a control transfer macro (CXFRC) is executed and the exit point named CMXF is active. Exit point CMXF is contained in CSECT CCNUCL. Exit point CMXF contains different parameters depending on the CXFRC ECB= parameter.

UCCCMXF allows user information to be passed from a parent to a child ECB. It is independent of macro servicing user exits.

General Conditions at Entry

The registers at entry to UCCCMXF are:

R2
Pointer to a 4-byte user data field where this routine can store data to be passed to the child ECB. R2 equals 0 if CXFRC was unable to obtain storage because of a low core condition.

R5
Set to 1 to show that ECB=DEFER was coded.

R7
Return address of CXFRC (CXFRTRN).

R9
If present, the address of the parent ECB. See Programming Considerations at Entry.

R11-R15
See User Exit Routines - Common Entry Conditions.

System Conditions at Entry

System state
Supervisor

System mask
Masked for I/O

Protect key
0

Address Space
SVM or EVM.

General Conditions at Entry

The registers at entry to UCCCMXF are:

R2
Address of the new ECB.

R5
Set to 0 to show that ECB=IMMED was coded.

R7
Return address of CXFRC (CXFRTRN).

R9
If present, the address of the parent ECB. See Programming Considerations at Entry.

R11-R15
See User Exit Routines - Common Entry Conditions.

System Conditions at Entry

System state
Supervisor

System mask
Masked for I/O

Protect key
0

Address Space
SVM.

Programming Considerations at Entry

  1. A parent ECB may or may not be present.
  2. See User Exit Routines - Common Entry Conditions.
  3. 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.