Directives

Directives

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Directives are assembler commands that appear in the source code but are not translated directly into opcodes. They are used to control the assembler: its input, output, and data allocation.

Many of the assembler directives have alternate names and formats. These may exist to provide backward compatibility with previous assemblers from Microchip and to be compatible with individual programming practices. If portable code is desired, it is recommended that programs be written using the specifications contained here.

Note: Although MPASM assembler is often used with MPLINK object linker, MPASM assembler directives are not supported by MPLINK linker. See MPLINK object linker documentation for more information on linker options to control listing and hex file output.

Directives discussed are:

Note: Directives are not case-sensitive, e.g., cblock may be executed as CBLOCK, cblock, Cblock, etc

• _ _BADRAM - Identify Unimplemented RAM

_ _BADROM - Identify Unimplemented ROM

_ _CONFIG - Set Processor Configuration Bits

_ _IDLOCS - Set Processor ID Locations

_ _MAXRAM - Define Maximum RAM Location

_ _MAXROM - Define Maximum ROM Location

#DEFINE - Define a Text Substitution Label

#INCLUDE - Include Additional Source File

#UNDEFINE - Delete a Substitution Label

BANKISEL - Generate Indirect Bank Selecting Code

BANKSEL - Generate Bank Selecting Code

CBLOCK - Define a Block of Constants

CODE - Begin an Object File Code Section

CODE_PACK - Begin an Object File Packed Code Section

CONSTANT - Declare Symbol Constant

DA - Store Strings in Program Memory

Data - Create Numeric and Text Data

DB - Declare Data of One Byte

DE - Declare EEPROM Data Byte

DT - Define Table

DW - Declare Data of One Word

ELSE - Begin Alternative Assembly Block to IF

END - End Program Block

ENDC - End an Automatic Constant Block

ENDIF - End Conditional Assembly Block

ENDM - End a Macro Definition

ENDW - End a While Loop

EQU - Define an Assembler Constant

ERROR - Issue an Error Message

ERRORLEVEL - Set Message Level

EXITM - Exit from a Macro

EXPAND - Expand Macro Listing

EXTERN - Declare an Externally Defined Label

FILL - Specify Memory Fill Value

GLOBAL - Export a Label

IDATA - Begin an Object File Initialized Data Section

IF - Begin Conditionally Assembled Code Block

IFDEF - Execute If Symbol has Been Defined

IFNDEF - Execute If Symbol has not Been Defined

LIST - Listing Options

LOCAL - Declare Local Macro Variable

MACRO - Declare Macro Definition

MESSG - Create User Defined Message

NOEXPAND - Turn off Macro Expansion

NOLIST - Turn off Listing Output

ORG - Set Program Origin

PAGE - Insert Listing Page Eject

PAGESEL - Generate Page Selecting Code

PROCESSOR - Set Processor Type

RADIX - Specify Default Radix

RES - Reserve Memory

SET - Define an Assembler Variable

SPACE - Insert Blank Listing Lines

SUBTITLE - Specify Program Subtitle

TITLE - Specify Program Title

UDATA - Begin an Object File Uninitialized Data Section

UDATA_ACS - Begin an Object File Access Uninitialized Data Section

UDATA_OVR - Begin an Object File Overlayed Uninitialized Data Section

UDATA_SHR - Begin an Object File Shared Uninitialized Data Section

VARIABLE - Declare Symbol Variable

WHILE - Perform Loop While Condition is True