A stacking PC routine can receive control with the same extended authorization index (EAX) value as the user who issued the PC instruction, or with a new EAX value. The EAX controls authorization for the PC routine to use access list entries. To specify a new EAX, use the EAX parameter on the ETDEF macro. The default is for the PC routine to use the user's EAX. For more information about the function of the EAX, see Types of access list entries.