nbsp;&nbsp;&nbsp; #IFNDEF&nbsp; <I>macro_label</I></PRE>
When invoked, the list of macro labels (established via DEFINE directives)
is searched. If the label is not found, the following lines of code are
assembled. If it is found, the input file is skipped until an ENDIF or
ELSE directive is found.
<H2>
<A NAME="IF"></A>IF</H2>
The IF directive can be used to optionally assemble a block of code dependent
on the value of a given expression. The format is as follows:
<PRE>&nbsp;&nbsp;&nbsp; #IF&nbsp;&nbsp;&nb