Motorola HC12 Manuale Utente

User’s Manual

MCUez HC12 Assembler

204

Macros

MOTOROLA

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.

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.

MACRO

ENDM

MEXIT

MLIST