Chapter 11 Writing Macro Control StatementsForced Termination of Macro Expansion (exitm) 21511.6 Forced Termination of Macro Expansion(exitm)Syntaxmacro_name macro parameter#ifndef identifierexitm#endif...endmFunctional descriptionThe exitm directive forcibly terminates macro expansion at the point it appears. Used in conjunctionwith an #ifndef directive, it can end macro expansion if an identifier is undefined. If the identifier hasbeen defined, expansion beyond #endif will be performed. (The conditions are reversed when #ifdef isused.)Coding rulesIn addition to #ifdef–#endif, all directives listed in chapter 10 "Writing Assembler Control Statements"section 10.5, “Conditional Assembly”, can be used.The exitm directive can be used at any location. The assembler will terminate macro expansion after itappears.The exitm directive can only be used within macro definitions.Usage exampleUsage example with #ifb directiveA source file is shown below. The identifier TEST is used for the condition. In main the first macro callis made with TEST undefined. This causes exitm to be executed, so jsr debug will not be expanded.TEST is defined before the second macro call, so here the statements after #endif will be assembled.
