HLASM Language Reference

Terms, Literals, and Expressions
Self-Defining Terms
A self-defining term lets you specify a value explicitly. With self-defining terms, you
can also specify decimal, binary, hexadecimal, or character data. If the DBCS
assembler option is specified, you can specify a graphic self-defining term that
contains pure double-byte data, or include double-byte data in character
self-defining terms. These terms have absolute values and can be used as
absolute terms in expressions to represent bit configurations, absolute addresses,
displacements, length or other modifiers, or duplication factors.
Using Self-Defining Terms: Self-defining terms represent machine language
binary values and are absolute terms. Their values do not change upon program
relocation. Some examples of self-defining terms and the binary values they
represent are given below:
Self-Defining Term Decimal Value Binary Value
15 15 1111
241 241 1111 1
B'1111' 15 1111
B'11111' 241 1111 1
B'11' 257 1 1
X'F' 15 1111
X'F1' 241 1111 1
X'11' 257 1 1
C'1' 241 1111 1
C'A' 193 11 1
C'AB' 49,62 11 1 11 1
G'' 17,89 1 1 11 1
The assembler carries the values represented by self-defining terms to 4 bytes or
32 bits, the high-order bit of which is the sign bit. (A '1' in the sign bit indicates a
negative value; a '0' indicates a positive value.)
The use of a self-defining term is distinct from the use of data constants or literals.
When you use a self-defining term in a machine instruction statement, its value is
used to determine the binary value that is assembled into the instruction. When a
data constant is referred to or a literal is specified in the operand of an instruction,
its address is assembled into the instruction. Self-defining terms are always
right-justified. Truncation or padding with zeros, if necessary, occurs on the left.
Decimal Self-Defining Term: A decimal self-defining term is simply an unsigned
decimal number written as a sequence of decimal digits. High-order zeros may be
used (for example, 7). Limitations on the value of the term depend on its use.
For example, a decimal term that designates a general register should have a value
between 0 and 15. A decimal term that represents an address should not exceed
the size of storage. In any case, a decimal term may not consist of more than 10
digits, nor exceed 2,147,483,647 (2 31 −1). A decimal self-defining term is
assembled as its binary equivalent. Some examples of decimal self-defining terms
are: 8, 147, 492, and 21.
34 HLASM V1R5 Language Reference