XPI register usage

Before you can issue an XPI call from a global user exit program, you must move the contents of the parameter UEPSTACK (the kernel stack entry) of DFHUEPAR to the exit program's register 13.

The XPI function expansion uses registers 0, 1, 14, and 15, so the exit program must save and restore them if necessary around an XPI call.

For an example of how to use EXEC CICS® commands and XPI calls in the same exit program, see Global user exit sample program DFH$XTSE.