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Section 3: Assembler
TI
-
89 / TI
-
92 Plus Sierra C Assembler Reference Manual
Not for Distribution
Beta Version February 2, 2001
.ifndef — Assemble If Symbol Not Defined
Syntax
.ifndef
symbol
Description
symbol
Specifies a user-defined symbol.
The
.ifndef
directive introduces a conditional assembly block. If the specified
symbol
symbol
is not defined when the directive is encountered, then the
statements between this directive and the first matching
.elifdef
,
.else
, or
.endif
directive are assembled and the remainder of the block is skipped. Otherwise,
the statements associated with the
.ifdef
directive are skipped and control
passes to the aforementioned matching directive.
Conditional assembly directives can be nested to 40 levels.
Example
.ifndef serial
move.l #parallel_dev,io_func
.endif
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