11: Macros

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An assembly language macro is a predefined set of instructions that can easily be inserted wherever needed. Once defined, the macro can be used as many times as necessary. It is useful when the same set of code must be utilized numerous times. A macro can be useful to reduce the amount of coding, streamline programs, and reduce errors from repetitive coding.

The assembler contains a powerful macro processor, which supports conditional assembly, multi-level file inclusion, and two forms of macros (single-line and multi-line), and a 'context stack' mechanism for extra macro power. Before using a macro, it must be defined. Macro definitions should be placed in the source file before the data and code sections. The macro is used in the text (code) section. The following sections will present a detailed example with the definition and use.

11.1: Single-Line Macros
There are two key types of macros; single-line macros and multi-line macros.
11.2: Multi-Line Macros
Multi-line macros can include a varying number of lines (including one). The multi-line macros are more useful and the following sections will focus primarily on multi-line macros.
11.3: Macro Example
The following example program demonstrates the definition and use of a simple macro.
11.4: Debugging Macros
The code for a macro will not be displayed in the debugger source window. When a macro is working correctly, this is very convenient. However, when debugging macros, the code must be viewable.
11.5: Exercises