Chapter 10 Writing Assembler Control Statements
182 Purpose of This Chapter
10.1 Purpose of This Chapter
Assembler control statements are statements that control assembler processing. They specify include
files and refinement of the identifier and control conditional assembly.
Include files are used to place definitions of constants, memory areas, I/O ports, and bit assignments
common to the entire program in separate files. They read in during assembly.
Identifier definement names a variable or a set of steps, and replace the name (the identifier) to the string
that has been defined.
Conditional assembly allows the assembler to evaluate conditions, and then to select a block of
statements to assemble depending on whether the conditions are fulfilled or not.
This chapter describes these functions and how to code them, and provides examples of actual use.
Many directives used in conditional assembly are used only within macro definitions. Refer to chapter
11, "Writing Macro Statements", as needed.

Common coding rules

Here are some rules common to coding of all assembly control statements.
The assembler directive should be coded from the first column of its statement. Both upper and lower
case letters can be used.
The characters that can be used as identifiers are upper and lower case letter, digits, and underscores ( _
). However, the first character must not be a digit.
Further conditional assembly directives can be used within a block of conditional assembly directives.
Up to 255 nesting levels are allowed.
The #else directive and the second block can be omitted. Refer to section 10.4, "Conditional
Assembly", for details about the second block.
An expression combines symbols, self-reference address symbols, and constants with operators into an
equation that returns a single value as its result. The value must have the attribute abs (absolute). Refer
to section 8.7, "Expressions", regarding attributes of expressions.
Document conventions
Symbols used in this chapter have the following meanings.
[ ] Contents of brackets [ ] may be omitted.