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Assembly Language Fundamentals 73
Literals can be part of expressions as well as having expressions as part of them. Since they
ultimately are replaced by an address (pointing to a specific location within a literal pool), their
"type" is "relocatable". See the section on "Expressions" later in this Chapter.
Basically, a literal means "the address of {expression}". An example should help in the under-
standing of literals. Suppose that you want to store the value 1 into the A register. There are
two ways you could accomplish that purpose. You could code -
or, you could use a literal and code -
:
::~j
:::::!
Using the literal method is easier and is more self-documenting. While the literal form strictly
says "load A with the contents of the address of the constant 1" , it can also be read as "load A
with the constant 1", and this short-hand version can be an excellent way of self-documenting
your programs, not to mention the elimination of a lot of unnecessar'y symbols.
Nesting Literals
Since literals use expressions, and literals may be used in expressions, it is possible to have a
literal within a literal (nesting). In fact, it may be done to any depth, though the most useful
form of nesting is a single level.
Suppose you want to initialize a variable to the value of pi each time you enter a routine. A
nested literal would be a way of accomplishing this in a clean, straight-forward fashion -
:::::::::::::'; ..
~
. , ..... :::",>:::: : .... , .. ' : .
J
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