gtpi1m29 | System Installation Support Reference |
User exit routine UCCSVC is invoked from the SVC Macro Decoder for all
SVCs, both direct and indexed, if the exit point named SVC is active.
Exit point SVC is in CSECT CCMCDC.
General Conditions at Entry
The registers at entry to UCCSVC are:
- R6
- Address of the macro entry in the macro decoder table.
- R8
- Base address of E-type program that issued the SVC macro.
- R9
- Address of the ECB.
- R11-R15
- See User Exit Routines - Common Entry Conditions.
System Conditions at Entry
- System state
- Supervisor
- System mask
- Masked for I/O Interrupts
- Protect key
- 0
- Address state
- EVM.
Programming Considerations at Entry
- The contents of program registers R0-R7 have been saved in the ECB
register save area.
- To preserve the integrity of the stack, user processing must
not issue an SVC macro because this would cause the stack register
to be reinitialized and the current saved data to be lost.
- The SVC exit point occurs before the formatting of the entry in the macro
trace table.
- 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.