C166/ST10 Cross-Assembler, Linker/Locator, Utilities ... - Tasking

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Software Concept 1−41
− a name followed by a ’:’ (e.g. LAB1: )
− a LABEL directive
− a PROC directive
Like a variable, a label has three attributes, two are the same as those of a
variable:
Section: Same as variable.
Offset: Same as variable.
Type: Specifies the type of JuMP or CALL that must be made to that
location. There are two types:
NEAR: This type represents a label that is accessed by a
JuMP or CALL that lies within the same physical
segment. In this case, only the offset of the label
is used in the JuMP or CALL instruction.
FAR: This type represents a label that is accessed
from a different segment. A far label is
represented in the JuMP or CALL instruction by
its offset and its segment number.
A special form of defining a label is the PROC directive. This form
specifies a sequence of code that is CALLed just as a subroutine in a
high−level language. The PROC directive defines a label with the type,
either NEAR or FAR. It also defines a context for the RET instruction so
that the assembler can determine the type of RET to code (either RET or a
RETS).
When you define a variable or label, the assembler stores its definition,
which includes the above attributes.
1.10.2.1 DEFINING CODE LABELS
’Code’ labels can be defined by:
or
label:
label: {NEAR|FAR}