Conditional Assembly

The A166 Assembler supports conditional program assembly using several conditional assembly directives. Conditional assembly may be used to implement different program versions or different memory models within a single source file. Using conditional assembly, you can easily maintain one source module that satisfies several applications.

There are two distinct sets of conditional controls.

• Conditional controls prefixed with the dollar-sign character ('$') are conditional directives. They can only test symbols that are defined using the $SET and $RESET directives.
• Conditional controls with no preceding dollar-sign are conditional statements that may test a wider range of defined symbols. However, they may not test symbols that are defined with the $SET and $RESET directives.

The following assembler directives are provided for conditional assembly:

Note

• Text blocks which are conditionally assembled must be enclosed by $IF, $ELSEIF, $ELSE, and $ENDIF or by IF, ELSEIF, ELSE, and ENDIF.
• The $SET and $RESET directives may be used on the command-line to define symbols used in conditional directives.
• Up to ten $IF or IF blocks may be nested. If a block is not translated, the nested conditional blocks, that are part of this block, are also skipped.