Motorola HC12 Macros, 9.4 Defining a Macro

User’s Manual MCUez HC12 Assembler

204 Macros MOTOROLA

Macros

statements generated by a macro call are inserted in the source file at the

position where the macro is invoked.

To call a macro, write the macro name in the operation field of a source

statement. Place the arguments in the operand field. The macro may contain

conditional assembly directives that cause the assembler to produce inline

coding variations of the macro definition.

Macro calls produce inline code to perform a predefined function. Each time the

macro is called, code is inserted in the normal flow of the program so that the

generated instructions are executed in line with the rest of the program.

9.4 Defining a Macro

The definition of a macro consists of four parts:

1. Header statement, a MACRO directive with a label that names the macro

2. Body of the macro, a sequential list of assembler statements, some

possibly including argument placeholders

3. The ENDM directive that terminates the macro definition

4. The MEXIT directive that stops macro expansion

The body of a macro is a sequence of assembler source statements. Macro

parameters are defined by parameter designators within these source

statements. Valid macro definition statements include the set of assembly

language instructions, assembler directives, and calls to previously defined

macros. However, macro definitions may not be nested.

NOTE:

Refer to Section 8. Assembler Directives for information about the

, and

directives.