A stacking PC routine can receive control with the secondary address space number (SASN) set to one of two values:

• SASN can equal the number of the user's primary address space (the address space from which the PC instruction was issued).
• SASN can equal the number of the service provider's address space (the address space where the PC routine executes)

The SASN parameter on the ETDEF macro determines the SASN value. The default is for SASN to equal the number of the user's primary address space.

Here are two examples of how you might use the SASN parameter:

• If the PC routine does not run in AR mode and you want to access data in the user's address space (by using the MVCP or MVCS instructions), specify SASN=OLD. This will give the PC routine the authority it needs to issue those two instructions.
• If you do not need or want the PC routine to have secondary authority to the user's address space, specify SASN=NEW.