In this information, each macro description includes a syntax diagram near the beginning of the macro description. The diagram shows how to code the macro. The syntax diagram does not explain the meanings of the parameters; the meanings are explained in the parameter descriptions that follow the syntax diagram.
The syntax tables assume that the standard begin, end, and continue columns are used. Thus, column 1 is assumed as the begin column. To change the begin, end, and continue columns, use the ICTL instruction to establish the coding format you want to use. If you do not use ICTL, the assembler recognizes the standard columns. To code the ICTL instruction, see HLASM Language Reference.
Figure 1 shows a sample macro, TEST, and
summarizes all the coding information that is available for it. The
table is divided into three columns, A, B, and C.
Figure 1. Sample Macro Syntax Diagram
- Column A and Column B contain those parameters that are allowed for the macro. Column A contains those parameters that are required; column B contains those parameters which are optional.
- If a single line appears, as shown in A1 and B1, then that is the only available choice for the particular parameter.
- If two or more lines appear together, as shown in A2 and B2, the parameters on those lines are mutually exclusive, that is, you can code any one of those parameters.
- A further distinction is made between mandatory and optional parameters. The parameter descriptions that follow the syntax table clearly identify those parameters which are optional.
- The third column, C, provides additional information about coding the macro.
When substitution of a variable is required in column C, the following
classifications are used:
- Variable
- Classification
- Symbol
- Any symbol valid in the assembler language. The symbol can be as long as the supported maximum length of a name entry in the assembler you are using.
- Decimal digit
- Any decimal digit up to and including the value indicated in the parameter description. If both symbol and decimal digit are indicated, an absolute expression is also allowed.
- Register (2)-(12)
- One of general purpose registers 2 through 12, specified within parentheses, previously loaded with the right-adjusted value or address indicated in the parameter description. You must set the unused high-order bits to zero. You can designate the register symbolically or with an absolute expression.
- Register (0)
- General purpose register 0, previously loaded with the right-adjusted value or address indicated in the parameter description. You must set the unused high-order bits to zero. Designate the register as (0) only.
- Register (1)
- General purpose register 1, previously loaded with the right-adjusted value or address indicated in the parameter description. You must set the unused high-order bits to zero. Designate the register as (1) only.
- Register (15)
- General purpose register 15, previously loaded with the right-adjusted value or address indicated in the parameter description. You must set the unused high-order bits to zero. Designate the register as (15) only.
- RX-type address
- Any address that is valid in an RX-type instruction (for example, LA).
- RS-type address
- Any address that is valid in an RS-type instruction (for example, STM).
- RS-type name
- Any name that is valid in an RS-type instruction (for example, STM).
- A-type address
- Any address that can be written in an A-type address constant.
- Default
- A value that is used in default of a specified value; that is, the value the system assumes if the parameter is not coded.
Use the parameters to specify the services and options to be performed,
and write them according to the following rules:
- If the selected parameter is written in all capital letters (for example, MATH, HIST, or FMT=HEX), code the parameter exactly as shown.
- If the selected parameter is written in italics (for example, grade), substitute the indicated value, address, or name.
- If the selected parameter is a combination of capital letters and italics separated by an equal sign (for example, DATA=data addr), code the capital letters and equal sign as shown, and then make the indicated substitution for the italics.
- Read the table from top to bottom.
- Code commas and parentheses exactly as shown.
- Positional parameters (parameters without equal signs) appear first; you must code them in the order shown. You may code keyword parameters (parameters with equal signs) in any order.
- If you select a parameter, read the third column before proceeding to the next parameter. The third column often contains coding restrictions for the parameter.