Making a PC routine available to selected address spaces

Characteristics of the PC routines that the entry table defines determines which macros the service provider must issue. The following figure lists the macros that must be issued.

The figure is divided into three columns. For a basic PC routine, refer to the left column. For a stacking PC routine where SASN=OLD is specified, refer to the center column. For a stacking PC routine where SASN=NEW is specified, refer to the right column. (U) identifies macros that must be issued by service provider code that is running in the user's address space. Several macros shown in the figure must be issued in a specific sequence. Therefore, IBM® recommends that the service provider issue the macros in the listed sequence.

Basic PC Routine	Stacking PC Routine
Basic PC Routine	SASN=OLD	SASN=NEW
AXRES AXSET LXRES (See note 1) ETDEF ETCRE ATSET (U) ETCON (U) (See note 2) PCLINK	AXRES AXSET LXRES (See note 1) ETDEF ETCRE ATSET (U) ETCON (U) (See note 2)	LXRES (See note 1) ETDEF ETCRE ETCON (U) (See note 2)
Note: Use a non-system LX. To determine whether address space authorization (PT and SSAR authority) is needed before issuing the ETCON macro, see Address space authorization for basic PC routines and Address space authorization for stacking PC routines.

Linkage Index (LX)

Regardless of the types of PC routines that the entry table defines, the service provider must always issue the LXRES macro to reserve a non-system LX. The rest of the macros that the service provider must issue depend on the types of PC routines the entry table will define.