IBM SC33-1683-02 - Manual (Page 326)

*************************************************************************
* The next seven instructions form the normal start of a global user *
* exit program, setting the program addressing mode to 31-bit, saving *
* the calling program's registers, establishing base addressing, and *
* establishing the addressing of the user exit parameter list. *
*************************************************************************
*
GXPI CSECT
GXPI AMODE 31 SET TO 31-BIT ADDRESSING
*
SAVE (14,12) SAVE CALLING PROGRAM'S REGISTERS
*
LR R11,R15 SET UP USER EXIT PROGRAM'S
USING GXPI,R11 BASE REGISTER
*
LR R2,R1 SET UP ADDRESSING FOR USER
USING DFHUEPAR,R2 EXIT PARAMETER LIST -- USE
* REGISTER 2 AS XPI CALLS USE
* REGISTER 1
*
**************************************************************************
* Before issuing an XPI function call, set up addressing to XPI *
* parameter list. *
*************************************************************************
*
L R5,UEPXSTOR SET UP ADDRESSING FOR XPI
* PARAMETER LIST
*
USING DFHSMMC_ARG,R5 MAP PARAMETER LIST
*
*************************************************************************
* Before issuing an XPI function call, you must ensure that register *
* 13 addresses the kernel stack. *
*************************************************************************
*
L R13,UEPSTACK ADDRESS KERNEL STACK
*
Figure 11. Global user exit program with XPI (Part 2 of 5)
XPI examples
294 CICS TS for OS/390: CICS Customization Guide