Motorola HC12 User Manual

Assembler Syntax

Expressions

MCUez HC12 Assembler

User’s Manual

MOTOROLA

Assembler Syntax

155

An expression is composed of one or more symbols or constants, which are
combined with unary or binary operators. Valid symbols in expressions are:

•

User-defined symbols

•

External symbols

•

The special symbol * (asterisk) represents the value of the location
counter at the beginning of the instruction or directive, even if several
arguments are specified. In the following example, the asterisk
represents the location counter at the beginning of the DC directive:

DC.W   1, 2, *-2

Once a valid expression has been fully evaluated by the assembler, it is reduced
to one of the following types of expressions.

•

Absolute expression — The expression has been reduced to an absolute
value, which is independent of the start address of any relocatable
section. Thus, it is a constant.

•

Simple relocatable expression — The expression evaluates to an absolute
offset from the start of a single relocatable section.

•

Complex relocatable expression — The expression neither evaluates to
an absolute expression nor to a simple relocatable expression. The
assembler does not support such expressions.

<
<=
>
>=

Less than
Less or equal to
Greater than
Greater or equal to

Left to right

=, ==
!=, <>

Equal to
Not Equal to

Left to right

&

Bitwise AND

Left to right

^

Bitwise exclusive OR

Left to right

|

Bitwise OR

Left to right