Page 103 - DCAP507_SYSTEM_SOFTWARE

Unit 7: Macro Language

 Defining MACROS or MACROX does not define RDBUFF and the other macroinstructions. Notes
These definitions are developed only when an invocation of MACROS or MACROX is
expanded.
 A one pass microprocessor that can swap between macro definition and macro expansion
is able to manage macros like these.

 There are three main data structures included in our macro processor.

Definition Table (DEFTAB)

1. The macro definition themselves are accumulated in definition table (DEFTAB), which
comprises the macro prototype and statements that make up the macro body.
2. Comment lines from macro definition are not entered into DEFTAB since they will not be
a part of macro expansion.

Name Table (NAMTAB)

1. References to macro instruction parameters are transformed to a positional entered into
NAMTAB, which provides the index to DEFTAB.

2. For every macro instruction defined, NAMTAB comprises pointers to beginning an end of
definition in DEFTAB.

Argument Table (ARGTAB)

1. The third Data Structure in an argument table (ARGTAB), which is utilized throughout
expansion of macro invocations.
2. When macro invocation statements are predictable, the arguments are amassed in ARGTAB
according to their position in argument list.

3. As the macro is expanded, arguments from ARGTAB are replaced for the corresponding
parameters in the macro body.

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