HLASM Language Reference

Assembler Language Coding Conventions
| An operation entry is mandatory, and it must appear on the same line as any
| name entry.
For machine and assembler instructions, it must be a valid symbol at assembly
time (after substitution for variable symbols, if specified), consisting of 63 or
fewer alphanumeric characters, the first which must be alphabetic. Most
standard symbolic operation codes are five characters or fewer. For a
description of machine instructions, see the applicable Principles of Operation
manual. For a summary of assembler instructions, see Appendix A,
“Assembler Instructions.”
The standard set of codes can be changed by OPSYN instructions (see
“OPSYN Instruction” on page 198).
For macro instructions, the operation entry can be any valid symbol.
An operation entry cannot be continued on the next statement.
Operand Entries: Operand entries contain zero or more operands that identify
and describe data to be acted upon by the instruction, by indicating such
information as storage locations, masks, storage area lengths, or types of data.
The following rules apply to operands:
One or more operands are usually required, depending on the instruction.
Operands must be separated by commas. No spaces are allowed between the
operands and the commas that separate them.
A space normally indicates the end of the operand entry, unless the operand is
in single quotes. This applies to machine, assembler, and macro instructions.
| A space does not end the operand in some types of SET statement. Spaces
| that do not end operands are discussed further at:
| – “Arithmetic (SETA) Expressions” on page 352
| – “Logical (SETB) Expressions” on page 365
| – “Character (SETC) Expressions” on page 371
| There are two examples of operands containing spaces in Figure 10 on
| page 26; the last box in Row 3, and the middle box in Row 4.
| The alternative statement format uses slightly different rules. For more
| information, see “Alternative Formats for a Macro Instruction” on page 298.
The following instruction is correctly coded:
LA R1,4+5 No space
The following instruction may appear to be the same, but is not:
LA R1,4 + 5 Spaces included
In this example, the embedded space means that the operand finishes after “4.”
There is no assembler error, but the result is a LA R1,4, which may not be what
you intended.
A space inside unquoted parentheses is an error, and leads to a diagnostic. The
following instruction is correctly coded:
DC CL(L'STRLEN)' ' Space within quotes
The following instruction, with an extra space, is not correct:
20 HLASM V1R5 Language Reference