Text Preprocessor

The text preprocessor is a functional unit within the assembler that performs the text preprocessing translation phase. During text preprocessing, the following actions are performed:

• Language Elements are recognized.

• Text equates and macros are expanded.

• Macro directives and conditional assembly directives are recognized and processed.

• The preprocessed output is passed on to the assembler for final processing.

This section also describes the various types of preprocessor directives:

┌─────────────────────────┬─────────────────────────┬─────────────────────────┐│Type                     │Function                 │Directives               │
├─────────────────────────┼─────────────────────────┼─────────────────────────┤
│Conditional Assembly     │Tests for a specified    │IF                       │
│                         │condition and assembles a│IFB                      │
│                         │block of statements if   │IFDEF                    │
│                         │the condition is true.   │IFDIFI                   │
│                         │                         │IFE                      │
│                         │                         │IFIDN                    │
│                         │                         │IFNB                     │
│                         │                         │IFNDEF                   │
│                         │                         │IF1                      │
│                         │                         │IF2                      │
│                         │                         │ELSE                     │
│                         │                         │ENDIF                    │
├─────────────────────────┼─────────────────────────┼─────────────────────────┤
│Text Equate              │Allows assignment of     │CATSTR                   │
│                         │simple text strings to a │EQU                      │
│                         │symbolic name. Provides  │INSTR                    │
│                         │functions for expanding  │SIZESTR                  │
│                         │and operating on the     │SUBSTR                   │
│                         │values.                  │                         │
├─────────────────────────┼─────────────────────────┼─────────────────────────┤
│Macro                    │Provides text processing │ENDM                     │
│                         │that is done sequentially│EXITM                    │
│                         │at assembly time. By the │FOR                      │
│                         │end of assembly, ALP     │FORC                     │
│                         │expands all macros and   │IRP                      │
│                         │assembles the resulting  │IRPC                     │
│                         │text into object code.   │LOCAL                    │
│                         │                         │MACRO                    │
│                         │                         │PURGE                    │
│                         │                         │REPEAT                   │
│                         │                         │REPT                     │
├─────────────────────────┼─────────────────────────┼─────────────────────────┤
│Miscellaneous            │Miscellaneous text       │COMMENT                  │
│                         │processing functions.    │ECHO                     │
│                         │                         │%OUT                     │
│                         │                         │INCLUDE                  │
└─────────────────────────┴─────────────────────────┴─────────────────────────┘