HLASM Language Reference

Terms, Literals, and Expressions
Terms, Literals, and Expressions
The most basic element of the assembler language is the term. Terms may be
used alone, or in combination with other terms in expressions. This section
describes the different types of terms used in the assembler language, and how
they can be used.
Terms
A term is the smallest element of the assembler language that represents a distinct
and separate value. It can, therefore, be used alone or in combination with other
terms to form expressions. Terms are classified as absolute or relocatable,
depending on the effect of program relocation upon them. Program relocation is
the loading of the object program into storage locations other than those originally
assigned by the assembler. Terms have absolute or relocatable values that are
assigned by the assembler or that are inherent in the terms themselves.
A term is absolute if its value does not change upon program relocation. A term is
relocatable if its value changes by n if the origin of the control section in which it
appears is relocated by n bytes.
Terms in Parentheses: Terms in parentheses are reduced to a single value; thus
the terms in parentheses, in effect, become a single term.
You can use arithmetically combined terms, enclosed in parentheses, in
combination with terms outside the parentheses, as follows:
14+BETA-(GAMMA-LAMBDA)
When the assembler encounters terms in parentheses in combination with other
terms, it first reduces the combination of terms inside the parentheses to a single
value which may be absolute or relocatable, depending on the combination of
terms. This value is then used in reducing the rest of the combination to another
single value.
You can include terms in parentheses within a set of terms in parentheses:
A+B-(C+D-(E+F)+1)
The innermost set of terms in parentheses is evaluated first. Any number of levels
of parentheses are allowed. A level of parentheses is a left parenthesis and its
corresponding right parenthesis. An arithmetic combination of terms is evaluated
as described in “Expressions” on page 44. Figure 12 summarizes the various
types of terms, and gives a reference to the page number that discusses the term
and the rules for using it.
Figure 12 (Page 1 of 2). Summary of Terms
Terms
Term
can be
absolute
Term can
be
relocatable
Value is
assigned
by
assembler
Value is
inherent
in term
Symbols X X X 29
| Literals
X
X
X
41
Self-defining terms X X 34
Page
reference
28 HLASM V1R5 Language Reference