Directives

The Ax51 Assembler provides a number of directives you may use to control source file assembly. Directives are composed of one or more letters or digits and, unless otherwise specified, may be specified after the filename on the command line or within the source file when preceded by a dollar sign ('$'). For example:

A51 SAMPLE.A51 SYMBOLS DEBUG

$SYMBOLS DEBUG

$SYMBOLS
$DEBUG

The source file to assemble is SAMPLE.A51 and SYMBOLS and DEBUG are the directives.

Assembler directives may be divided into two groups:

Primary directives are specified on the assembler command line or in first few lines of the assembly source file. These directives control how the assembler behaves for the entire module. If conflicting primary directives are specified on the command line and in the source file, the command line directive takes precedence.
General directives may be specified on the command line or anywhere in the source file. These directives control the immediate behaviour of the assembler and may be changed during assembly.

Note

Syntax is the same for directives specified on the command line and those specified in the source file.
Some directives may not be specified on the command line. If one of these directives is specified on the command line, the assembler generates a fatal error and aborts.

The following table is an alphabetical list of the control directives available in the Ax51 Assembler.

Directive	Group	Description
CASE	Primary	Enables case-sensitive symbol names.
COND	General	Includes (in the listing file) conditional source lines skipped by the preprocessor.
DATE	Primary	Specifies the date to use in the listing file header.
DEBUG	Primary	Includes debugging information in the object file.
DEFINE	Primary	Defines C preprocessor symbols on the command line.
ECRM	Primary	Allow expansion of generic CALL instruction to ECALL for the NXP 80C51MX devices.
EJECT¹	General	Inserts a form feed character into the listing file.
ELSE	General	Assemble block if the condition of a previous IF is false.
ELSEIF	General	Assemble block if condition is true and a previous IF or ELSEIF is false.
ENDIF	General	Ends an IF block.
ERRORPRINT	Primary	Specifies the file name for error messages.
GEN	General	Includes all macro expansions in the listing file.
IF	General	Assemble block if condition is true.
INCDIR	Primary	Sets additional include file paths.
INCLUDE²	General	Includes the contents of another file.
LIST	General	Includes the assembly source text in the listing file.
MACRO	Primary	Enables preprocessor expansion of standard macros.
MOD_CONT	Primary	Enables 24-bit contiguous addressing for Dallas Semiconductor devices.
MOD_MX51	Primary	Enables instruction set extensions for the NXP 80C51MX architecture.
MOD51	Primary	Enables code generation and defines SFRs for classic 8051 devices.
MPL	Primary	Enables preprocessor expansion of MPL macros.
NOAMAKE	Primary	Excludes build information from the object file.
NOCASE	Primary	Disables case-sensitive symbol names. All symbols are converted to uppercase.
NOCOND	Primary	Excludes (from the listing file) conditional source lines skipped by the preprocessor.
NODEBUG	Primary	Excludes debugging information from the object file.
NOERRORPRINT	Primary	Disables error messages output to the screen.
NOGEN	General	Excludes macro expansions from the listing file.
NOLINES	Primary	Excludes line number information from the generated object module.
NOLIST	General	Excludes the assembly source text from the listing file.
NOMACRO	Primary	Disables preprocessor expansion of standard and MPL macros.
NOMOD51	Primary	Suppresses SFRs definitions for classic 8051 devices
NOMPL	Primary	Disables preprocessor expansion of MPL macros.
NOOBJECT	Primary	Disables object file generation.
NOPRINT	Primary	Disables listing file generation.
NOREGISTERBANK	Primary	Disables memory space reservation for register banks.
NOSYMBOLS	Primary	Excludes the symbol table from the listing file.
NOSYMLIST	General	Excludes subsequently defined symbols from the symbol table.
NOXREF	Primary	Excludes the cross-reference table from the listing file.
OBJECT	Primary	Specifies the name for the object file.
PAGELENGTH	Primary	Specifies the number of lines on a page in the listing file.
PAGEWIDTH	Primary	Specifies the number of characters on a line in the listing file.
PRINT	Primary	Specifies the name for the listing file.
REGISTERBANK	Primary	Reserves memory space for register banks.
REGUSE	General	Specifies registers modified by the specified function.
RESET	General	Sets symbols, which may be tested by IF or ELSEIF, to false.
RESTORE¹	General	Restores settings for the LIST and GEN directives.
SAVE¹	General	Saves settings for the LIST and GEN directives.
SET	General	Sets symbols, which may be tested by IF or ELSEIF, to true or a specified value.
SYMBOLS	Primary	Includes the symbol table in the listing file.
SYMLIST	General	Includes subsequently defined symbols in the symbol table.
TITLE	Primary	Specifies the page header title in the listing file.
XREF	Primary	Includes the cross-reference table in the listing file.

Note

These directives may not be specified on the command line. They may only be specified in the source file.
Primary directives may not be specified after an INCLUDE directive.