Subparameters with GENCB, MODCB, SHOWCB, and TESTCB

The addresses, names, numbers, and options required with subparameters in GENCB, MODCB, SHOWCB, and TESTCB can be expressed in a variety of ways:

An absolute numeric expression, for example, STRNO=3 and COPIES=10.
A code or a list of codes separated by commas and enclosed in parentheses, for example, OPTCD=KEY or OPTCD=(KEY,DIR,IN).
A character string, for example, DDNAME=DATASET.
A register from 2 through 12 that contains an address or numeric value, for example, SYNAD=(3); equated labels can be used to designate a register, for example, SYNAD=(ERR), where the following equate statement has been included in the program: ERR EQU 3.
An expression of the form (S,scon), where scon is an expression valid for an S-type address constant, including the base-displacement form. The contents of the base register are added to the displacement to obtain the value of the keyword. For example, if the value of the keyword being represented is a numeric value (that is, COPIES, LENGTH, RECLEN), the contents of the base register are added to the displacement to determine the numeric value. If the value of the keyword being represented is an address constant (that is, WAREA, EXLST, EODAD, ACB), the contents of the base register are added to the displacement to determine the value of the address constant.
An expression of the form (*,scon), where scon is an expression valid for an S-type address constant, including the base-displacement form. The address specified by scon is indirect, that is, it is the address of an area that contains the value of the keyword. The contents of the base register are added to the displacement to determine the address of the fullword of storage that contains the value of the keyword.
If an indirect S-type address constant is used, the value it points to must meet the following criteria:
- If it is a numeric quantity or an address, it must occupy a fullword of storage.
- If it is an alphanumeric character string, it must occupy two words of storage, be left aligned, and be filled on the right with blanks.
An expression valid for a relocatable A-type address constant, for example, AREA=MYAREA+4.

The specified keyword determines the type of expressions that can be used. Also, register and S-type address constants cannot be used when MF=L is specified.