Register 1 contains the address of the exit routine parameter list as shown in Table 1, with a storage protect key of 8. You can use the ADRDEX01 mapping macro to map this parameter list.

Table 1. ADRDYEXT_EXIT1 Parameter List

Offset	Length or Bit Pattern	Description
00 (X'00')	8	The EBCDIC 'ADRDEX01' ID.
08 (X'08')	2	The length of the parameter list, which is set to 48 bytes.
10 (X'0A')	1	The function code, as follows: Value Meaning X'01' The request is to process open data sets. A class transition could not be performed because DFSMSdss could not serialize on the data set and the SMS management class ACS routine for class transition specified that an EXIT should be invoked.
11 (X'0B')	1	The function code extension. For function code X'01', processing of open data sets, the function extension codes are: Value Meaning X'01' The call is to close an open data set X'02' The call is to open a closed data set
12 (X'0C')	4	Flags set to describe the DSS being performed, as follows: Byte 0: Bit Meaning 0 DEFRAG OPERATION 1 COPY OPERATION 2 RESTORE OPERATION 3 DUMP OPERATION 4 PRINT OPERATION 5 COPYDUMP OPERATION 6 NEWALLOC OPERATION 7 COMPRESS OPERATION Byte 1: Bit Meaning 0 RELEASE OPERATION 1 CONVERT VOLUME OPERATION 2 BUILDSA OPERATION 3 DEFRAG CONSOLIDATE 4 CGCREATED OPERATION 5 CONSOLID OPERATION 6 RESERVED 7 RESERVED Byte 2: Bit Meaning 0 INPUT DSN IS VSAM Byte 3 is unused.
16 (X'10')	4	The address on entry of a the data set name to be processed.
20 (X'14')	4	The address on entry of the 44-byte name of the integrated catalog facility catalog in which the data set is cataloged.
24 (X'18')	4	The address of the volume serial number.
28 (X'1C')	4	The address of an 18-byte area that defines who holds the data set enqueue. In order, this includes: The 2-byte ASID of the ENQ requester The 8-byte job name of the ENQ requester The 8-byte system name of the ENQ requester.