sp;&nbsp; <I>expr</I></PRE>
If the expression <I>expr</I> evaluates to non-zero, the following block
of code is assembled (until an ENDIF or ELSE is encountered).
<H2>
<A NAME="INCLUDE"></A>INCLUDE</H2>
The INCLUDE directive reads in and assembles the indicated source file.
INCLUDEs can be nested up to four levels. This allows a convenient means
to keep common definitions, declarations, or subroutines in files to be
included as needed. The format is as follows:
<PRE>#INCLUDE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb