Use the data control block DSECT (DCBD) macro to identify the DCB field names symbolically. If you load a base register with a DCB address, you can refer to any field symbolically. You can code the DCBD macro once to describe all DCBs.

The DCBD macro generates a dummy control section (DSECT) named IHADCB. Each field name symbol consists of DCB followed by the first 5 letters of the keyword subparameter for the DCB macro. For example, the symbolic name of the block size parameter field is DCBBLKSI. (For other DCB field names see z/OS DFSMS Macro Instructions for Data Sets.)

The attributes of each DCB field are defined in the dummy control section. Use the DCB macro's assembler listing to determine the length attribute and the alignment of each DCB field.