Here's a list of all control commands and a description, what they do:
.A16
Valid only in 65816 mode. Switch the accumulator to 16 bit.
Note: This command will not emit any code, it will tell the assembler to create 16 bit operands for immediate accumulator adressing mode.
See also:
.SMART
.A8
Valid only in 65816 mode. Switch the accumulator to 8 bit.
Note: This command will not emit any code, it will tell the assembler to create 8 bit operands for immediate accu adressing mode.
See also:
.SMART
.ADDR
Define word sized data. In 6502 mode, this is an alias for .WORD and
may be used for better readability if the data words are address values.
In 65816 mode, the address is forced to be 16 bit wide to fit into the
current segment. See also .FARADDR. The command must be followed by a
sequence of (not necessarily constant) expressions.
Example:
.addr $0D00, $AF13, _Clear
See:
.FARADDR
.ALIGN
Align data to a given boundary. The command expects a constant integer argument that must be a power of two, plus an optional second argument in byte range. If there is a second argument, it is used as fill value, otherwise the value defined in the linker configuration file is used (the default for this value is zero).
Since alignment depends on the base address of the module, you must give the same (or a greater) alignment for the segment when linking. The linker will give you a warning, if you don't do that.
Example:
.align 256
.ASCIIZ
Define a string with a trailing zero.
Example:
Msg: .asciiz "Hello world"
This will put the string "Hello world" followed by a binary zero into the current segment. There may be more strings separated by commas, but the binary zero is only appended once (after the last one).
.AUTOIMPORT
Is followd by a plus or a minus character. When switched on (using a +), undefined symbols are automatically marked as import instead of giving errors. When switched off (which is the default so this does not make much sense), this does not happen and an error message is displayed. The state of the autoimport flag is evaluated when the complete source was translated, before outputing actual code, so it is not possible to switch this feature on or off for separate sections of code. The last setting is used for all symbols.
You should probably not use this switch because it delays error messages about undefined symbols until the link stage. The cc65 compiler (which is supposed to produce correct assembler code in all circumstances, something which is not true for most assembler programmers) will insert this command to avoid importing each and every routine from the runtime library.
Example:
.autoimport + ; Switch on auto import
.BLANK
Builtin function. The function evaluates its argument in braces and
yields "false" if the argument is non blank (there is an argument), and
"true" if there is no argument. As an example, the .IFBLANK statement
may be replaced by
.if .blank(arg)
.BSS
Switch to the BSS segment. The name of the BSS segment is always "BSS", so this is a shortcut for
.segment "BSS"
See also the
.SEGMENT command.
.BYTE
Define byte sized data. Must be followed by a sequence of (byte ranged) expressions or strings.
Example:
.byte "Hello world", $0D, $00
.CASE
Switch on or off case sensitivity on identifiers. The default is off (that is, identifiers are case sensitive), but may be changed by the -i switch on the command line. The command must be followed by a '+' or '-' character to switch the option on or off respectively.
Example:
.case - ; Identifiers are not case sensitive
.CODE
Switch to the CODE segment. The name of the CODE segment is always "CODE", so this is a shortcut for
.segment "CODE"
See also the
.SEGMENT command.
.CONDES
Export a symbol and mark it in a special way. The linker is able to build tables of all such symbols. This may be used to automatically create a list of functions needed to initialize linked library modules.
Note: The linker has a feature to build a table of marked routines, but it
is your code that must call these routines, so just declaring a symbol with
.CONDES does nothing by itself.
All symbols are exported as an absolute (16 bit) symbol. You don't need to
use an additional
.EXPORT statement, this
is implied by .CONDES.
.CONDES is followed by the type, which may be constructor,
destructor or a numeric value between 0 and 6 (where 0 is the same as
specifiying constructor and 1 is equal to specifying destructor).
The
.CONSTRUCTOR and
.DESTRUCTOR commands are actually shortcuts
for .CONDES with a type of constructor resp. destructor.
After the type, an optional priority may be specified. If no priority is given, the default priority of 7 is used. Be careful when assigning priorities to your own module constructors so they won't interfere with the ones in the cc65 library.
Example:
.condes ModuleInit, constructor
.condes ModInit, 0, 16
See the
.CONSTRUCTOR and
.DESTRUCTOR commands and the separate section
Module constructors/destructors explaining the
feature in more detail.
.CONCAT
Builtin function. The function allows to concatenate a list of string
constants separated by commas. The result is a string constant that
is the concatentation of all arguments. This function is most useful
in macros and when used together with the .STRING builtin function.
The function may be used in any case where a string constant is
expected.
Example:
.include .concat ("myheader", ".", "inc)
This is the same as the command
.include "myheader.inc"
.CONST
Builtin function. The function evaluates its argument in braces and yields "true" if the argument is a constant expression (that is, an expression that yields a constant value at assembly time) and "false" otherwise. As an example, the .IFCONST statement may be replaced by
.if .const(a + 3)
.CONSTRUCTOR
Export a symbol and mark it as a module constructor. This may be used together with the linker to build a table of constructor subroutines that are called by the startup code.
Note: The linker has a feature to build a table of marked routines, but it is your code that must call these routines, so just declaring a symbol as constructor does nothing by itself.
A constructor is always exported as an absolute (16 bit) symbol. You don't
need to use an additional .export statement, this is implied by
.constructor. It may have an optional priority that is separated by a
comma. If no priority is given, the default priority of 7 is used. Be
careful when assigning priorities to your own module constructors so they
won't interfere with the ones in the cc65 library.
Example:
.constructor ModuleInit
.constructor ModInit, 16
See the
.CONDES and
.DESTRUCTOR commands and the separate section
Module constructors/destructors explaining the
feature in more detail.
.CPU
Reading this pseudo variable will give a constant integer value that tells which instruction set is currently enabled. Possible values are:
0 --> 6502
1 --> 65SC02
2 --> 65SC816
3 --> SunPlus SPC
It may be used to replace the .IFPxx pseudo instructions or to construct even more complex expressions.
Example:
.if (.cpu = 0) .or (.cpu = 1)
txa
pha
tya
pha
.else
phx
phy
.endif
.DATA
Switch to the DATA segment. The name of the DATA segment is always "DATA", so this is a shortcut for
.segment "DATA"
See also the
.SEGMENT command.
.DBYT
Define word sized data with the hi and lo bytes swapped (use .WORD to
create word sized data in native 65XX format). Must be followed by a
sequence of (word ranged) expressions.
Example:
.dbyt $1234, $4512
This will emit the bytes
$12 $34 $45 $12
into the current segment in that order.
.DEBUGINFO
Switch on or off debug info generation. The default is off (that is, the object file will not contain debug infos), but may be changed by the -g switch on the command line. The command must be followed by a '+' or '-' character to switch the option on or off respectively.
Example:
.debuginfo + ; Generate debug info
.DEFINE
Start a define style macro definition. The command is followed by an identifier (the macro name) and optionally by a list of formal arguments in braces. See section Macros.
.DEF, .DEFINED
Builtin function. The function expects an identifier as argument in braces.
The argument is evaluated, and the function yields "true" if the identifier
is a symbol that is already defined somewhere in the source file up to the
current position. Otherwise the function yields false. As an example, the
.IFDEF statement may be replaced by
.if .defined(a)
.DESTRUCTOR
Export a symbol and mark it as a module destructor. This may be used together with the linker to build a table of destructor subroutines that are called by the startup code.
Note: The linker has a feature to build a table of marked routines, but it is your code that must call these routines, so just declaring a symbol as constructor does nothing by itself.
A destructor is always exported as an absolute (16 bit) symbol. You don't
need to use an additional .export statement, this is implied by
.destructor. It may have an optional priority that is separated by a
comma. If no priority is given, the default priority of 7 is used. Be
careful when assigning priorities to your own module destructors so they
won't interfere with the ones in the cc65 library.
Example:
.destructor ModuleDone
.destructor ModDone, 16
See the
.CONDES and
.CONSTRUCTOR commands and the separate
section
Module constructors/destructors explaining
the feature in more detail.
.DWORD
Define dword sized data (4 bytes) Must be followed by a sequence of expressions.
Example:
.dword $12344512, $12FA489
.ELSE
Conditional assembly: Reverse the current condition.
.ELSEIF
Conditional assembly: Reverse current condition and test a new one.
.END
Forced end of assembly. Assembly stops at this point, even if the command is read from an include file.
.ENDIF
Conditional assembly: Close a
.IF... or
.ELSE branch.
.ENDMAC, .ENDMACRO
End of macro definition (see section Macros).
.ENDPROC
End of local lexical level (see
.PROC).
.ENDREP, .ENDREPEAT
End a
.REPEAT block.
.ERROR
Force an assembly error. The assembler will output an error message preceeded by "User error" and will not produce an object file.
This command may be used to check for initial conditions that must be set before assembling a source file.
Example:
.if foo = 1
...
.elseif bar = 1
...
.else
.error "Must define foo or bar!"
.endif
See also the
.WARNING and
.OUT directives.
.EXITMAC, .EXITMACRO
Abort a macro expansion immidiately. This command is often useful in recursive macros. See separate section Macros.
.EXPORT
Make symbols accessible from other modules. Must be followed by a comma separated list of symbols to export.
Example:
.export foo, bar
See:
.EXPORTZP
.EXPORTZP
Make symbols accessible from other modules. Must be followed by a comma separated list of symbols to export. The exported symbols are explicitly marked as zero page symols.
Example:
.exportzp foo, bar
See:
.EXPORT
.FARADDR
Define far (24 bit) address data. The command must be followed by a sequence of (not necessarily constant) expressions.
Example:
.faraddr DrawCircle, DrawRectangle, DrawHexagon
See:
.ADDR
.FEATURE
This directive may be used to enable one or more compatibility features
of the assembler. While the use of .FEATURE should be avoided when
possible, it may be useful when porting sources written for other
assemblers. There is no way to switch a feature off, once you have
enabled it, so using
.FEATURE xxx
will enable the feature until end of assembly is reached.
The following features are available:
dollar_is_pcThe dollar sign may be used as an alias for the star (`*'), which gives the value of the current PC in expressions. Note: Assignment to the pseudo variable is not allowed.
labels_without_colonsAllow labels without a trailing colon. These labels are only accepted, if they start at the beginning of a line (no leading white space).
loose_string_termAccept single quotes as well as double quotes as terminators for string constants.
loose_char_termAccept single quotes as well as double quotes as terminators for char constants.
at_in_identifiersAccept the at character (`@') as a valid character in identifiers. The at character is not allowed to start an identifier, even with this feature enabled.
dollar_in_identifiersAccept the dollar sign (`$') as a valid character in identifiers. The at character is not allowed to start an identifier, even with this feature enabled.
pc_assignmentAllow assignments to the PC symbol (`*' or `$' if dollar_is_pc
is enabled). Such an assignment is handled identical to the
.ORG command (which is usually not needed, so just
removing the lines with the assignments may also be an option when porting
code written for older assemblers).
It is also possible to specify features on the command line using the
--feature command line option.
This is useful when translating sources written for older assemblers, when
you don't want to change the source code.
As an example, to translate sources written for Andre Fachats xa65 assembler, the features
labels_without_colons, pc_assignment, loose_char_term
may be helpful. They do not make ca65 completely compatible, so you may not be able to translate the sources without changes, even when enabling these features. However, I have found several sources that translate without problems when enabling these features on the command line.
.FILEOPT, .FOPT
Insert an option string into the object file. There are two forms of this command, one specifies the option by a keyword, the second specifies it as a number. Since usage of the second one needs knowledge of the internal encoding, its use is not recommended and I will only describe the first form here.
The command is followed by one of the keywords
author
comment
compiler
a comma and a string. The option is written into the object file together with the string value. This is currently unidirectional and there is no way to actually use these options once they are in the object file.
Examples:
.fileopt comment, "Code stolen from my brother"
.fileopt compiler, "BASIC 2.0"
.fopt author, "J. R. User"
.GLOBAL
Declare symbols as global. Must be followed by a comma separated list of
symbols to declare. Symbols from the list, that are defined somewhere in the
source, are exported, all others are imported. Additional
.IMPORT or
.EXPORT commands for the same symbol are allowed.
Example:
.global foo, bar
.GLOBALZP
Declare symbols as global. Must be followed by a comma separated list of
symbols to declare. Symbols from the list, that are defined somewhere in the
source, are exported, all others are imported. Additional
.IMPORTZP or
.EXPORTZP commands for the same symbol are allowed. The symbols
in the list are explicitly marked as zero page symols.
Example:
.globalzp foo, bar
.I16
Valid only in 65816 mode. Switch the index registers to 16 bit.
Note: This command will not emit any code, it will tell the assembler to create 16 bit operands for immediate operands.
See also the
.I8 and
.SMART commands.
.I8
Valid only in 65816 mode. Switch the index registers to 8 bit.
Note: This command will not emit any code, it will tell the assembler to create 8 bit operands for immediate operands.
See also the
.I16 and
.SMART commands.
.IF
Conditional assembly: Evalute an expression and switch assembler output on or off depending on the expression. The expression must be a constant expression, that is, all operands must be defined.
A expression value of zero evaluates to FALSE, any other value evaluates to TRUE.
.IFBLANK
Conditional assembly: Check if there are any remaining tokens in this line,
and evaluate to FALSE if this is the case, and to TRUE otherwise. If the
condition is not true, further lines are not assembled until an
.ESLE,
.ELSEIF or
.ENDIF directive.
This command is often used to check if a macro parameter was given. Since an empty macro parameter will evaluate to nothing, the condition will evaluate to FALSE if an empty parameter was given.
Example:
.macro arg1, arg2
.ifblank arg2
lda #arg1
.else
lda #arg2
.endif
.endmacro
See also:
.BLANK
.IFCONST
Conditional assembly: Evaluate an expression and switch assembler output on or off depending on the constness of the expression.
A const expression evaluates to to TRUE, a non const expression (one containing an imported or currently undefined symbol) evaluates to FALSE.
See also:
.CONST
.IFDEF
Conditional assembly: Check if a symbol is defined. Must be followed by a symbol name. The condition is true if the the given symbol is already defined, and false otherwise.
See also:
.DEFINED
.IFNBLANK
Conditional assembly: Check if there are any remaining tokens in this line,
and evaluate to TRUE if this is the case, and to FALSE otherwise. If the
condition is not true, further lines are not assembled until an
.ELSE,
.ELSEIF or
.ENDIF directive.
This command is often used to check if a macro parameter was given. Since an empty macro parameter will evaluate to nothing, the condition will evaluate to FALSE if an empty parameter was given.
Example:
.macro arg1, arg2
lda #arg1
.ifnblank arg2
lda #arg2
.endif
.endmacro
See also:
.BLANK
.IFNDEF
Conditional assembly: Check if a symbol is defined. Must be followed by a symbol name. The condition is true if the the given symbol is not defined, and false otherwise.
See also:
.DEFINED
.IFNREF
Conditional assembly: Check if a symbol is referenced. Must be followed by a symbol name. The condition is true if if the the given symbol was not referenced before, and false otherwise.
See also:
.REFERENCED
.IFP02
Conditional assembly: Check if the assembler is currently in 6502 mode
(see
.P02 command).
.IFP816
Conditional assembly: Check if the assembler is currently in 65816 mode
(see
.P816 command).
.IFPC02
Conditional assembly: Check if the assembler is currently in 65C02 mode
(see
.PC02 command).
.IFREF
Conditional assembly: Check if a symbol is referenced. Must be followed by a symbol name. The condition is true if if the the given symbol was referenced before, and false otherwise.
This command may be used to build subroutine libraries in include files (you may use separate object modules for this purpose too).
Example:
.ifref ToHex ; If someone used this subroutine
ToHex: tay ; Define subroutine
lda HexTab,y
rts
.endif
See also:
.REFERENCED
.IMPORT
Import a symbol from another module. The command is followed by a comma separated list of symbols to import.
Example:
.import foo, bar
See:
.IMPORTZP
.IMPORTZP
Import a symbol from another module. The command is followed by a comma separated list of symbols to import. The symbols are explicitly imported as zero page symbols (that is, symbols with values in byte range).
Example:
.includezp foo, bar
See:
.IMPORT
.INCBIN
Include a file as binary data. The command expects a string argument that is the name of a file to include literally in the current segment.
Example:
.incbin "sprites.dat"
.INCLUDE
Include another file. Include files may be nested up to a depth of 16.
Example:
.include "subs.inc"
.LEFT
Builtin function. Extracts the left part of a given token list.
Syntax:
.LEFT (<int expr>, <token list>)
The first integer expression gives the number of tokens to extract from the token list. The second argument is the token list itself.
Example:
To check in a macro if the given argument has a '#' as first token (immidiate addressing mode), use something like this:
.macro ldax arg
...
.if (.match (.left (1, arg), #))
; ldax called with immidiate operand
...
.endif
...
.endmacro
See also the
.MID and
.RIGHT builtin functions.
.LINECONT
Switch on or off line continuations using the backslash character before a newline. The option is off by default. Note: Line continuations do not work in a comment. A backslash at the end of a comment is treated as part of the comment and does not trigger line continuation. The command must be followed by a '+' or '-' character to switch the option on or off respectively.
Example:
.linecont + ; Allow line continuations
lda \
#$20 ; This is legal now
.LIST
Enable output to the listing. The command must be followed by a boolean
switch ("on", "off", "+" or "-") and will enable or disable listing
output.
The option has no effect if the listing is not enabled by the command line
switch -l. If -l is used, an internal counter is set to 1. Lines are output
to the listing file, if the counter is greater than zero, and suppressed if
the counter is zero. Each use of .LIST will increment or decrement the
counter.
Example:
.list on ; Enable listing output
.LISTBYTES
Set, how many bytes are shown in the listing for one source line. The default is 12, so the listing will show only the first 12 bytes for any source line that generates more than 12 bytes of code or data. The directive needs an argument, which is either "unlimited", or an integer constant in the range 4..255.
Examples:
.listbytes unlimited ; List all bytes
.listbytes 12 ; List the first 12 bytes
.incbin "data.bin" ; Include large binary file
.LOCAL
This command may only be used inside a macro definition. It declares a list of identifiers as local to the macro expansion.
A problem when using macros are labels: Since they don't change their name,
you get a "duplicate symbol" error if the macro is expanded the second time.
Labels declared with
.LOCAL have their
name mapped to an internal unique name (___ABCD__) with each macro
invocation.
Some other assemblers start a new lexical block inside a macro expansion.
This has some drawbacks however, since that will not allow any symbol
to be visible outside a macro, a feature that is sometimes useful. The
.LOCAL command is in my eyes a better way
to address the problem.
You get an error when using
.LOCAL outside
a macro.
.LOCALCHAR
Defines the character that start "cheap" local labels. You may use one of '@' and '?' as start character. The default is '@'.
Cheap local labels are labels that are visible only between two non
cheap labels. This way you can reuse identifiers like "loop" without
using explicit lexical nesting.
Example:
.localchar '?'
Clear: lda #$00 ; Global label
?Loop: sta Mem,y ; Local label
dey
bne ?Loop ; Ok
rts
Sub: ... ; New global label
bne ?Loop ; ERROR: Unknown identifier!
.MACPACK
Insert a predefined macro package. The command is followed by an identifier specifying the macro package to insert. Available macro packages are:
generic Defines generic macros like add and sub.
longbranch Defines conditional long jump macros.
Including a macro package twice, or including a macro package that redefines already existing macros will lead to an error.
Example:
.macpack longbranch ; Include macro package
cmp #$20 ; Set condition codes
jne Label ; Jump long on condition
Macro packages are explained in more detail in section Macro packages).
.MAC, .MACRO
Start a classic macro definition. The command is followed by an identifier (the macro name) and optionally by a comma separated list of identifiers that are macro parameters.
See section Macros).
.MATCH
Builtin function. Matches two token lists against each other. This is most useful within macros, since macros are not stored as strings, but as lists of tokens.
The syntax is
.MATCH(<token list #1>, <token list #2>)
Both token list may contain arbitrary tokens with the exception of the terminator token (comma resp. right parenthesis) and
Often a macro parameter is used for any of the token lists.
Please note that the function does only compare tokens, not token
attributes. So any number is equal to any other number, regardless of the
actual value. The same is true for strings. If you need to compare tokens
and token attributes, use the
.XMATCH function.
Example:
Assume the macro ASR, that will shift right the accumulator by one,
while honoring the sign bit. The builtin processor instructions will allow
an optional "A" for accu addressing for instructions like ROL and
ROR. We will use the
.MATCH function
to check for this and print and error for invalid calls.
.macro asr arg
.if (.not .blank(arg)) .and (.not .match (arg, a))
.error "Syntax error"
.endif
cmp #$80 ; Bit 7 into carry
lsr a ; Shit carry into bit 7
.endmacro
The macro will only accept no arguments, or one argument that must be the reserved keyword "A".
See:
.XMATCH
.MID
Builtin function. Takes a starting index, a count and a token list as arguments. Will return part of the token list.
Syntax:
.MID (<int expr>, <int expr>, <token list>)
The first integer expression gives the starting token in the list (the first token has index 0). The second integer expression gives the number of tokens to extract from the token list. The third argument is the token list itself.
Example:
To check in a macro if the given argument has a '#' as first token
(immidiate addressing mode), use something like this:
.macro ldax arg
...
.if (.match (.mid (0, 1, arg), #))
; ldax called with immidiate operand
...
.endif
...
.endmacro
See also the
.LEFT and
.RIGHT builtin functions.
.ORG
Start a section of absolute code. The command is followed by a constant
expression that gives the new PC counter location for which the code is
assembled. Use
.RELOC to switch back to
relocatable code.
Please note that you do not need this command in most cases. Placing code at a specific address is the job of the linker, not the assembler, so there is usually no reason to assemble code to a specific address.
You may not switch segments while inside a section of absolute code.
Example:
.org $7FF ; Emit code starting at $7FF
.OUT
Output a string to the console without producing an error. This command
is similiar to .ERROR, however, it does not force an assembler error
that prevents the creation of an object file.
Example:
.out "This code was written by the codebuster(tm)"
See also the
.WARNING and
.ERROR directives.
.P02
Enable the 6502 instruction set, disable 65C02 and 65816 instructions.
This is the default if not overridden by the --cpu command line
option.
.P816
Enable the 65816 instruction set. This is a superset of the 65C02 and 6502 instruction sets.
.PAGELEN, .PAGELENGTH
Set the page length for the listing. Must be followed by an integer
constant. The value may be "unlimited", or in the range 32 to 127. The
statement has no effect if no listing is generated. The default value is -1
(unlimited) but may be overridden by the --pagelength command line
option. Beware: Since ca65 is a one pass assembler, the listing is generated
after assembly is complete, you cannot use multiple line lengths with one
source. Instead, the value set with the last .PAGELENGTH is used.
Examples:
.pagelength 66 ; Use 66 lines per listing page
.pagelength unlimited ; Unlimited page length
.PARAMCOUNT
This builtin pseudo variable is only available in macros. It is replaced by the actual number of parameters that were given in the macro invocation.
Example:
.macro foo arg1, arg2, arg3
.if .paramcount <> 3
.error "Too few parameters for macro foo"
.endif
...
.endmacro
See section Macros.
.PC02
Enable the 65C02 instructions set. This instruction set includes all 6502 instructions.
.PROC
Start a nested lexical level. All new symbols from now on are in the local
lexical level and are not accessible from outside. Symbols defined outside
this local level may be accessed as long as their names are not used for new
symbols inside the level. Symbols names in other lexical levels do not
clash, so you may use the same names for identifiers. The lexical level ends
when the
.ENDPROC command is read.
Lexical levels may be nested up to a depth of 16.
The command may be followed by an identifier, in this case the identifier is declared in the outer level as a label having the value of the program counter at the start of the lexical level.
Note: Macro names are always in the global level and in a separate name space. There is no special reason for this, it's just that I've never had any need for local macro definitions.
Example:
.proc Clear ; Define Clear subroutine, start new level
lda #$00
L1: sta Mem,y ; L1 is local and does not cause a
; duplicate symbol error if used in other
; places
dey
bne L1 ; Reference local symbol
rts
.endproc ; Leave lexical level
See:
.ENDPROC
.REF, .REFERENCED
Builtin function. The function expects an identifier as argument in braces.
The argument is evaluated, and the function yields "true" if the identifier
is a symbol that has already been referenced somewhere in the source file up
to the current position. Otherwise the function yields false. As an example,
the
.IFREF statement may be replaced by
.if .referenced(a)
See:
.DEFINED
.REPEAT
Repeat all commands between .REPEAT and
.ENDREPEAT constant number of times. The command is followed by
a constant expression that tells how many times the commands in the body
should get repeated. Optionally, a comma and an identifier may be specified.
If this identifier is found in the body of the repeat statement, it is
replaced by the current repeat count (starting with zero for the first time
the body is repeated).
.REPEAT statements may be nested. If you use the same repeat count
identifier for a nested .REPEAT statement, the one from the inner
level will be used, not the one from the outer level.
Example:
The following macro will emit a string that is "encrypted" in that all characters of the string are XORed by the value $55.
.macro Crypt Arg
.repeat .strlen(Arg), I
.byte .strat(Arg, I) .xor $55
.endrep
.endmacro
See:
.ENDREPEAT
.RELOC
Switch back to relocatable mode. See the
.ORG command.
.RES
Reserve storage. The command is followed by one or two constant expressions. The first one is mandatory and defines, how many bytes of storage should be defined. The second, optional expression must by a constant byte value that will be used as value of the data. If there is no fill value given, the linker will use the value defined in the linker configuration file (default: zero).
Example:
; Reserve 12 bytes of memory with value $AA
.res 12, $AA
.RIGHT
Builtin function. Extracts the right part of a given token list.
Syntax:
.RIGHT (<int expr>, <token list>)
The first integer expression gives the number of tokens to extract from the token list. The second argument is the token list itself.
See also the
.LEFT and
.MID builtin functions.
.RODATA
Switch to the RODATA segment. The name of the RODATA segment is always "RODATA", so this is a shortcut for
.segment "RODATA"
The RODATA segment is a segment that is used by the compiler for readonly data like string constants.
See also the
.SEGMENT command.
.SEGMENT
Switch to another segment. Code and data is always emitted into a segment, that is, a named section of data. The default segment is "CODE". There may be up to 254 different segments per object file (and up to 65534 per executable). There are shortcut commands for the most common segments ("CODE", "DATA" and "BSS").
The command is followed by a string containing the segment name (there
are some constraints for the name - as a rule of thumb use only those
segment names that would also be valid identifiers). There may also be
an optional attribute separated by a comma. Valid attributes are
"zeropage" and "absolute".
When specifying a segment for the first time, "absolute" is the default. For all other uses, the attribute specified the first time is the default.
"absolute" means that this is a segment with absolute addressing. That is, the segment will reside somewhere in core memory outside the zero page. "zeropage" means the opposite: The segment will be placed in the zero page and direct (short) addressing is possible for data in this segment.
Beware: Only labels in a segment with the zeropage attribute are marked as reachable by short addressing. The `*' (PC counter) operator will work as in other segments and will create absolute variable values.
Example:
.segment "ROM2" ; Switch to ROM2 segment
.segment "ZP2", zeropage ; New direct segment
.segment "ZP2" ; Ok, will use last attribute
.segment "ZP2", absolute ; Error, redecl mismatch
See:
.BSS,
.CODE,
.DATA and
.RODATA
.SMART
Switch on or off smart mode. The command must be followed by a '+' or '-' character to switch the option on or off respectively. The default is off (that is, the assembler doesn't try to be smart), but this default may be changed by the -s switch on the command line.
In smart mode the assembler will track usage of the REP and SEP
instructions in 65816 mode and update the operand sizes accordingly. If
the operand of such an instruction cannot be evaluated by the assembler
(for example, because the operand is an imported symbol), a warning is
issued. Beware: Since the assembler cannot trace the execution flow this
may lead to false results in some cases. If in doubt, use the .Inn and
.Ann instructions to tell the assembler about the current settings.
Example:
.smart ; Be smart
.smart - ; Stop being smart
.STRAT
Builtin function. The function accepts a string and an index as arguments and returns the value of the character at the given position as an integer value. The index is zero based.
Example:
.macro M Arg
; Check if the argument string starts with '#'
.if (.strat (Arg, 0) = '#')
...
.endif
.endmacro
.STRING
Builtin function. The function accepts an argument in braces and converts this argument into a string constant. The argument may be an identifier, or a constant numeric value.
Since you can use a string in the first place, the use of the function may not be obvious. However, it is useful in macros, or more complex setups.
Example:
; Emulate other assemblers:
.macro section name
.segment .string(name)
.endmacro
.STRLEN
Builtin function. The function accepts a string argument in braces and eveluates to the length of the string.
Example:
The following macro encodes a string as a pascal style string with a leading length byte.
.macro PString Arg
.byte .strlen(Arg), Arg
.endmacro
.TCOUNT
Builtin function. The function accepts a token list in braces. The function result is the number of tokens given as argument.
Example:
The ldax macro accepts the '#' token to denote immidiate addressing (as
with the normal 6502 instructions). To translate it into two separate 8 bit
load instructions, the '#' token has to get stripped from the argument:
.macro ldax arg
.if (.match (.mid (0, 1, arg), #))
; ldax called with immidiate operand
lda #<(.right (.tcount (arg)-1, arg))
ldx #>(.right (.tcount (arg)-1, arg))
.else
...
.endif
.endmacro
.WARNING
Force an assembly warning. The assembler will output a warning message
preceeded by "User warning". This warning will always be output, even if
other warnings are disabled with the
-W0
command line option.
This command may be used to output possible problems when assembling the source file.
Example:
.macro jne target
.local L1
.ifndef target
.warning "Forward jump in jne, cannot optimize!"
beq L1
jmp target
L1:
.else
...
.endif
.endmacro
See also the
.ERROR and
.OUT directives.
.WORD
Define word sized data. Must be followed by a sequence of (word ranged, but not necessarily constant) expressions.
Example:
.word $0D00, $AF13, _Clear
.XMATCH
Builtin function. Matches two token lists against each other. This is most useful within macros, since macros are not stored as strings, but as lists of tokens.
The syntax is
.XMATCH(<token list #1>, <token list #2>)
Both token list may contain arbitrary tokens with the exception of the terminator token (comma resp. right parenthesis) and
Often a macro parameter is used for any of the token lists.
The function compares tokens and token values. If you need a function
that just compares the type of tokens, have a look at the
.MATCH function.
See:
.MATCH
.ZEROPAGE
Switch to the ZEROPAGE segment and mark it as direct (zeropage) segment. The name of the ZEROPAGE segment is always "ZEROPAGE", so this is a shortcut for
.segment "ZEROPAGE", zeropage
Because of the "zeropage" attribute, labels declared in this segment are addressed using direct addressing mode if possible. You must instruct the linker to place this segment somewhere in the address range 0..$FF otherwise you will get errors.
See:
.SEGMENT