Registers at Entry

On entry to the status user routine, the registers contain the following information:

Register	Contents
GPR 0	Used as a work register by the system
GPR 1	Address of the status user routine parameter list (SEPL) mapped by the IXCYSEPL macro.
GPRs 2 - 12	Used as work registers by the system.
GPR 13	Address of a 72-byte work area for use by the status user routine. The user routine does not have to save and restore XCF's registers in this work area. The user routine can use this work area in any way it chooses.
GPR 14	Return address (the status user routine must return control to XCF through a BR 14 or a BSM 0,14.)
GPR 15	Entry point address of the status user routine.
ARs 0 - 15	Used as work registers by the system.