Explain Macro definition and call.

Macro: The assembly language programming frequently finds this necessary to repeat certain piece of code several times during the course of program. In such situations we get macro facility helpful. Whole process contains three steps:

a. Macro definition instruction

b. Macro call

c. Macro expansion

A macro definition is enclosed between a macro end statement and a macro header statement. Macro definitions are classically located at the start of a program. This contains:

a. A macro prototype statement

b. One or more model statements

c. Macro preprocessor

A macro call is called through writing the macro name into the mnemonics field of an assembly statement. Hence the syntax for the same:

< macro name >[< actual parameter spec >[,..]]

A macro call leads to macro expansion, throughout macro call expansion the macro call statement is replaced through the sequence of assembly statements.