HLASM Language Reference

Terms, Literals, and Expressions
The method of describing and specifying a constant as a literal is nearly identical to
the method of specifying it in a single operand of a DC assembler instruction. The
only difference is that the literal must start with an equal sign (=), which indicates to
| the assembler that a literal follows. The length of the literal, including the equal
| sign, constant type and modifiers, delimiters, and nominal values is limited to a
| maximum of 256 characters.
A literal may be coded as indicated here:
=1XL5'F3'
where the subfields are:
Duplication factor 1
Type
X
Modifiers
L5
Nominal value 'F3'
The following instruction shows one use of a literal:
GAMMA L 1,=F'274'
The statement GAMMA is a load instruction using a literal as the second operand.
When assembled, the second operand of the instruction refers to the relative
address at which the value F'274' is stored.
| You cannot rely on the ordering of literals in the literal pool remaining the same.
| For this reason, referring to a point that extends beyond the bounds of a literal is
| flagged with warning message ASMA015W. Here is an example of such a
| reference:
| BETA L 1,=F'274'+4
In general, literals can be used wherever a storage address is permitted as an
operand, including in conjunction with an index register in instructions with the RX
format. For example:
DELTA LH 5,=H'11,23,39,48,64'(6)
is equivalent to:
DELTA LH 5,LENGTHS(6)
.
.
.
LENGTHS DC
H'11,23,39,48,64'
See “DC Instruction” on page 126 for a description of how to specify the subfields
in a literal.
Literals cannot be used in any assembler instruction where a previously defined
| symbol is required, but length attribute references to previously defined literals are
| allowed. Literals are relocatable terms because the address of the literal, rather
than the literal-generated constant itself, is assembled in the statement that
references a literal. The assembler generates the literals, collects them, and places
them in a specific area of storage, as explained under “Literal Pool” on page 44.
Because the assembler determines the order in which literals are placed in the
literal pool, the effect of using two literals as paired relocatable terms (see “Paired
Relocatable Terms” on page 47) is unpredictable.
Chapter 2. Coding and Structure 43