CALCULATION SPECIFICATION

Calculation specifications are used to write the program instructions that are run when the program is called. The majority of an RPG program is made up of calculation specifications and definition specifications. All operations, including but not limited to, file processing, computations, and data manipulation, are performed with calculation specifications.

There are two formats for calculation specifications: the standard calculation specification and the alternate calculation specification. The standard calculation specification is used for most operations (i.e., program instructions). Although the alternate calculation specification is used by fewer operations, these operations control the program logic and most data manipulation. Consequently, RPG programs consist mostly of alternate calculation specifications.

There is no order or priority to either specification. The standard calculation specification can be intermixed with the alternate calculation specification. The layout of the two formats is designed to allow this transparency. Figures 2.13 and 2.14 illustrate the calculation specifications.

 .....CSRn01Factor1+++++++OpCode(ex)Factor2+++++++Result++++++++Len++DcHiLoEq.... 

Figure 2.13: Standard calculation specification.

 .....CSRn01..............OpCode(ex)Extended-factor2+++++++++++++++++++++++++++++ 

Figure 2.14: Alternate calculation specification with extended factor 2.

Calculation Specification Summary

Table 2.16 summarizes the calculation specifications.

Table 2.16: Calculation Specification Summary

Column	Title	Values	Description
6	Form type	C	Identifies this statement as a calculation specification.
7	Control code	*	The statement is ignored (it is a comment).
		/	The statement contains either a compiler directive, such as /COPY, /IF DEFINED, or a preprocessor directive, such as /EXEC SQL.
		+	The statement is a preprocessor continuation specification that began with /EXEC SQL on a previous line.
7 – 8	Control level indicator or subroutine notation	Blank	The statement is a normal statement or normal subroutine statement. No special control is specified. Control-level indicators cannot be specified within a subprocedure.
		AN/OR	The indicator conditioning on the previous statement is continued onto this line. The indicator condition of the previous line and/or the indicator condition of this line must be met before the operation can be performed. When AN/OR Is used, the operation must be specified on the last statement of the AN/OR group. There is no limit to the number of AN/OR continuations that can be specified for each operation.
		L0	Total-time calculation. Because level zero (L0) is always on, this controlling level indicator always tests true.
		L1 to L9	Total-time calculation. The control-level indicators are tested at total time (level break).
		LR	Total-time and last-record processing. The calculation statement is performed during total-time processing—after the last record indicator is set on.
		SR	Optional documentary notation to indicate a subroutine statement. Typically, SR is used only on the first and last statements of each subroutine to better identify the beginning and ending of the subroutine.
9 – 11	Conditioning indicators	Blank	No conditioning indicators are used to control whether or not this statement is performed. There should never be an entry in these columns if proper programming practices are followed.
		Any valid indicator(s)	The specified indicator(s) control the running of this calculation. If more than one indicator is required, the conditioning can be continued on subsequent calculation specifications by specifying an AN or an OR in the control level positions of the next calculation line. All valid indicators are allowed.
12 – 25	Factor 1	Blank	No factor 1 entry is specified. Several operations support an entry in factor 1, while others do not require factor 1.
		Any characters	The entry is used by the operation. The entry must match the requirements of the operation. All entries in factor 1 must be left-justified.
26 – 35	Operation code and operation extender		The name of the RPG instruction (operation) that is to be performed. Most operations use factor 1, factor 2, or the result field.
		Operation [(ex)]	The operation extender is optional for operations that support an extender. The extender must be enclosed in parentheses. It can appear anywhere following the operation. Typical operation extenders include P (pad), N (no record lock), and H (half-adjust). See Table 5.8 for operation extender rules.
			Extender	Description
			D	Pass operation descriptors.
			D	Test for valid date.
			E	Activate %ERROR and %STATUS.
			H	Half-adjust (round) result field.
			M	Use max-digits precision rules.
			N	Reset pointer to NULL.
			N	Avoid locking the record.
			P	Pad result field.
			R	Use result-field length precision rules.
			T	Test for valid time.
			Z	Test for valid timestamp.
36 – 49	Factor 2	Blank	No factor 2 entry is specified. Several operations support an entry in factor 2, while others do not require factor 2.
		Any characters	The entry is used by the operation. The entry must match the requirements of the operation. All entries in factor 2 must be left justified.
36 – 80	Extended Factor 2	Any characters	Any natural expression is specified.
			It can span multiple lines by continuing the expression onto addition lines in the extended factor 2 area. Only certain operations support the extended factor 2, including the following:
			Op Code	Description
			CALLP	Call a prototyped procedure.
			DOU	Do until.
			DOW	Do while.
			ELSEIF	Combined ELSE and IF operation
			EVAL	Evaluate an expression.
			EVALR	Evaluate, right adjust.
			FOR	Iterative FOR loop
			IF	Conditional IF.
			RETURN	Return value to caller.
			WHEN	Select/WHEN CASE.
50 – 63	Result field	Blank	No result field entry is specified. Several operations support an entry in the result field, while others do not require the result field.
		Variable name	The entry is used as the target of the operation. The entry must match the requirements of the operation. All entries in the result field must be left justified. The result field is normally used as the target of the operation. For example, if it is the target of a MOVE operation, the content of factor 2 is copied to the result-field entry.
64 – 68	Result field length	Blank	The result field is defined elsewhere in the program or it is not a definable value (e.g., a label or subroutine name).
		1 to 30	For numeric fields, the length of the result field.
		1 to 65535	For character fields, the length of the result field.
		-65534 to +65534	Relative length of the result field based on the field specified for factor 2 for a *LIKE DEFINE operation. The result field's length is the length of the field specified in factor 2, plus or minus the value specified.
69 – 70	Decimal positions	Blank	If the result field is specified and a result field length is also specified, the new field's data-type is character. If the result field length is blank, then these columns must also be blank. For the *LIKE DEFINE operation, the result field decimal positions must be blank.
		0 to 30	Number of decimal positions for the result field. (Valid only for numeric result fields.)
71 – 76	Resulting indicators	Blank	No resulting indicators are set on as a result of the operation.
		Any valid indicator	The resulting indicators are set according to the results of the operation. All but the following can be specified as resulting indicators: 1P, MR.
77 – 80			Not used.