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 addressing 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 addressing 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
.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).
.ASSERT
Add an assertion. The command is followed by an expression, an action
specifier, and an optional message that is output in case the assertion
fails. If no message was given, the string "Assertion failed" is used. The
action specifier may be one of warning
or error
. The assertion is
evaluated by the assembler if possible, and also passed to the linker in the
object file (if one is generated). The linker will then evaluate the
expression when segment placement has been done.
Example:
.assert * = $8000, error, "Code not at $8000"
The example assertion will check that the current location is at $8000,
when the output file is written, and abort with an error if this is not
the case. More complex expressions are possible. The action specifier
warning
outputs a warning, while the error
specifier outputs
an error message. In the latter case, generation of the output file is
suppressed in both the assembler and linker.
.AUTOIMPORT
Is followed 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 outputting 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
.BANKBYTES
Define byte sized data by extracting only the bank byte (that is, bits 16-23) from
each expression. This is equivalent to
.BYTE
with
the operator '^' prepended to each expression in its list.
Example:
.define MyTable TableItem0, TableItem1, TableItem2, TableItem3
TableLookupLo: .lobytes MyTable
TableLookupHi: .hibytes MyTable
TableLookupBank: .bankbytes MyTable
which is equivalent to
TableLookupLo: .byte <TableItem0, <TableItem1, <TableItem2, <TableItem3
TableLookupHi: .byte >TableItem0, >TableItem1, >TableItem2, >TableItem3
TableLookupBank: .byte ^TableItem0, ^TableItem1, ^TableItem2, ^TableItem3
See also:
.BYTE
,
.HIBYTES
,
.LOBYTES
.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.
.BYT, .BYTE
Define byte sized data. Must be followed by a sequence of (byte ranged) expressions or strings.
Example:
.byte "Hello "
.byt "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
.CHARMAP
Apply a custom mapping for characters. The command is followed by two
numbers in the range 1..255. The first one is the index of the source
character, the second one is the mapping. The mapping applies to all
character and string constants when they generate output, and overrides
a mapping table specified with the
-t
command line switch.
Example:
.charmap $41, $61 ; Map 'A' to 'a'
.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
specifying constructor
and 1 is equal to specifying destructor
).
The
.CONSTRUCTOR
,
.DESTRUCTOR
and
.INTERRUPTOR
commands are actually shortcuts for .CONDES
with a type of constructor
resp. destructor
or interruptor
.
After the type, an optional priority may be specified. Higher numeric values mean higher priority. 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
,
.DESTRUCTOR
and
.INTERRUPTOR
commands and the separate section
Module constructors/destructors explaining the feature in more
detail.
.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. Higher numeric values mean a higher priority. 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.
.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. Higher numerical values mean a higher priority. 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.
.ENDENUM
End a
.ENUM
declaration.
.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.
.ENDSCOPE
End of local lexical level (see
.SCOPE
).
.ENDSTRUCT
Ends a struct definition. See the
.STRUCT
command and the separate section named
"Structs and unions".
.ENUM
Start an enumeration. This directive is very similar to the C enum
keyword. If a name is given, a new scope is created for the enumeration,
otherwise the enumeration members are placed in the enclosing scope.
In the enumeration body, symbols are declared. The first symbol has a value of zero, and each following symbol will get the value of the preceding plus one. This behaviour may be overridden by an explicit assignment. Two symbols may have the same value.
Example:
.enum errorcodes
no_error
file_error
parse_error
.endenum
Above example will create a new scope named errorcodes
with three
symbols in it that get the values 0, 1 and 2 respectively. Another way
to write this would have been:
.scope errorcodes
no_error = 0
file_error = 1
parse_error = 2
.endscope
Please note that explicit scoping must be used to access the identifiers:
.word errorcodes::no_error
A more complex example:
.enum
EUNKNOWN = -1
EOK
EFILE
EBUSY
EAGAIN
EWOULDBLOCK = EAGAIN
.endenum
In this example, the enumeration does not have a name, which means that the
members will be visible in the enclosing scope and can be used in this scope
without explicit scoping. The first member (EUNKNOWN
) has the value -1.
The value for the following members is incremented by one, so EOK
would
be zero and so on. EWOULDBLOCK
is an alias for EGAIN
, so it has an
override for the value using an already defined symbol.
.ERROR
Force an assembly error. The assembler will output an error message preceded 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 immediately. 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, with each one optionally followed by an address specification and (also optional) an assignment. Using an additional assignment in the export statement allows to define and export a symbol in one statement. The default is to export the symbol with the address size it actually has. The assembler will issue a warning, if the symbol is exported with an address size smaller than the actual address size.
Examples:
.export foo
.export bar: far
.export foobar: far = foo * bar
.export baz := foobar, zap: far = baz - bar
As with constant definitions, using :=
instead of =
marks the
symbols as a label.
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 symbols. An assignment may be included in the
.EXPORTZP
statement. This allows to define and export a symbol in one
statement.
Examples:
.exportzp foo, bar
.exportzp baz := $02
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:
at_in_identifiers
Accept the at character (`@') as a valid character in identifiers. The at character is not allowed to start an identifier, even with this feature enabled.
c_comments
Allow C like comments using /*
and */
as left and right
comment terminators. Note that C comments may not be nested. There's also a
pitfall when using C like comments: All statements must be terminated by
"end-of-line". Using C like comments, it is possible to hide the newline,
which results in error messages. See the following non working example:
lda #$00 /* This comment hides the newline
*/ sta $82
dollar_in_identifiers
Accept the dollar sign (`$') as a valid character in identifiers. The dollar character is not allowed to start an identifier, even with this feature enabled.
dollar_is_pc
The 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_colons
Allow labels without a trailing colon. These labels are only accepted, if they start at the beginning of a line (no leading white space).
leading_dot_in_identifiers
Accept the dot (`.') as the first character of an identifier. This may be used for example to create macro names that start with a dot emulating control directives of other assemblers. Note however, that none of the reserved keywords built into the assembler, that starts with a dot, may be overridden. When using this feature, you may also get into trouble if later versions of the assembler define new keywords starting with a dot.
loose_char_term
Accept single quotes as well as double quotes as terminators for char constants.
loose_string_term
Accept single quotes as well as double quotes as terminators for string constants.
missing_char_term
Accept single quoted character constants where the terminating quote is missing.
lda #'a
Note: This does not work in conjunction with .FEATURE
loose_string_term
, since in this case the input would be ambiguous.
org_per_seg
This feature makes relocatable/absolute mode local to the current segment.
Using
.ORG
when org_per_seg
is in
effect will only enable absolute mode for the current segment. Dito for
.RELOC
.
pc_assignment
Allow 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).
ubiquitous_idents
Allow the use of instructions names as names for macros and symbols. This makes it possible to "overload" instructions by defining a macro with the same name. This does also make it possible to introduce hard to find errors in your code, so be careful!
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"
.FORCEIMPORT
Import an absolute symbol from another module. The command is followed by a
comma separated list of symbols to import. The command is similar to
.IMPORT
, but the import reference is always
written to the generated object file, even if the symbol is never referenced
(
.IMPORT
will not generate import
references for unused symbols).
Example:
.forceimport needthisone, needthistoo
See:
.IMPORT
.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 symbols.
Example:
.globalzp foo, bar
.HIBYTES
Define byte sized data by extracting only the high byte (that is, bits 8-15) from
each expression. This is equivalent to
.BYTE
with
the operator '>' prepended to each expression in its list.
Example:
.lobytes $1234, $2345, $3456, $4567
.hibytes $fedc, $edcb, $dcba, $cba9
which is equivalent to
.byte $34, $45, $56, $67
.byte $fe, $ed, $dc, $cb
Example:
.define MyTable TableItem0, TableItem1, TableItem2, TableItem3
TableLookupLo: .lobytes MyTable
TableLookupHi: .hibytes MyTable
which is equivalent to
TableLookupLo: .byte <TableItem0, <TableItem1, <TableItem2, <TableItem3
TableLookupHi: .byte >TableItem0, >TableItem1, >TableItem2, >TableItem3
See also:
.BYTE
,
.LOBYTES
,
.BANKBYTES
.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: Evaluate 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).
.IFPSC02
Conditional assembly: Check if the assembler is currently in 65SC02 mode
(see
.PSC02
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, with each one optionally followed by an address specification.
Example:
.import foo
.import bar: zeropage
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:
.importzp 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. In addition to that, a start offset and a size value may be specified, separated by commas. If no size is specified, all of the file from the start offset to end-of-file is used. If no start position is specified either, zero is assumed (which means that the whole file is inserted).
Example:
; Include whole file
.incbin "sprites.dat"
; Include file starting at offset 256
.incbin "music.dat", $100
; Read 100 bytes starting at offset 200
.incbin "graphics.dat", 200, 100
.INCLUDE
Include another file. Include files may be nested up to a depth of 16.
Example:
.include "subs.inc"
.INTERRUPTOR
Export a symbol and mark it as an interruptor. This may be used together with the linker to build a table of interruptor subroutines that are called in an interrupt.
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 interruptor does nothing by itself.
An interruptor is always exported as an absolute (16 bit) symbol. You don't
need to use an additional .export
statement, this is implied by
.interruptor
. It may have an optional priority that is separated by a
comma. Higher numeric values mean a higher priority. 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:
.interruptor IrqHandler
.interruptor Handler, 16
See the
.CONDES
command and the separate
section
Module constructors/destructors explaining
the feature in more detail.
.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
.LOBYTES
Define byte sized data by extracting only the low byte (that is, bits 0-7) from
each expression. This is equivalent to
.BYTE
with
the operator '<' prepended to each expression in its list.
Example:
.lobytes $1234, $2345, $3456, $4567
.hibytes $fedc, $edcb, $dcba, $cba9
which is equivalent to
.byte $34, $45, $56, $67
.byte $fe, $ed, $dc, $cb
Example:
.define MyTable TableItem0, TableItem1, TableItem2, TableItem3
TableLookupLo: .lobytes MyTable
TableLookupHi: .hibytes MyTable
which is equivalent to
TableLookupLo: .byte <TableItem0, <TableItem1, <TableItem2, <TableItem3
TableLookupHi: .byte >TableItem0, >TableItem1, >TableItem2, >TableItem3
See also:
.BYTE
,
.HIBYTES
,
.BANKBYTES
.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:
atari Defines the scrcode macro.
cbm Defines the scrcode macro.
cpu Defines constants for the .CPU variable.
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.
.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.
By default, absolute/relocatable mode is global (valid even when switching
segments). Using .FEATURE
org_per_seg
it can be made segment local.
Please note that you do not need .ORG
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.
Example:
.org $7FF ; Emit code starting at $7FF
.OUT
Output a string to the console without producing an error. This command
is similar 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 65SC02, 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 65SC02 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
.PC02
Enable the 65C02 instructions set. This instruction set includes all 6502 and 65SC02 instructions.
.POPSEG
Pop the last pushed segment from the stack, and set it.
This command will switch back to the segment that was last pushed onto the
segment stack using the
.PUSHSEG
command, and remove this entry from the stack.
The assembler will print an error message if the segment stack is empty when this command is issued.
See:
.PUSHSEG
.PROC
Start a nested lexical level with the given name and adds a symbol with this
name to the enclosing scope. All new symbols from now on are in the local
lexical level and are accessible from outside only via
explicit scope specification. 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 (this is an artificial limit to protect
against errors in the source).
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
.PSC02
Enable the 65SC02 instructions set. This instruction set includes all 6502 instructions.
.PUSHSEG
Push the currently active segment onto a stack. The entries on the stack include the name of the segment and the segment type. The stack has a size of 16 entries.
.PUSHSEG
allows together with
.POPSEG
to switch to another segment and to restore the old segment later, without
even knowing the name and type of the current segment.
The assembler will print an error message if the segment stack is already full, when this command is issued.
See:
.POPSEG
.RELOC
Switch back to relocatable mode. See the
.ORG
command.
.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) ^ $55
.endrep
.endmacro
See:
.ENDREPEAT
.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
.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.
.SCOPE
Start a nested lexical level with the given name. All new symbols from now
on are in the local lexical level and are accessible from outside only via
explicit scope specification. 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
.ENDSCOPE
command is
read. Lexical levels may be nested up to a depth of 16 (this is an
artificial limit to protect against errors in the source).
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:
.scope Error ; Start new scope named Error
None = 0 ; No error
File = 1 ; File error
Parse = 2 ; Parse error
.endscope ; Close lexical level
...
lda #Error::File ; Use symbol from scope Error
.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
address size separated by a colon. See the section covering
address sizes
for more information.
The default address size for a segment depends on the memory model specified on the command line. The default is "absolute", which means that you don't have to use an address size modifier in most cases.
"absolute" means that the is a segment with 16 bit (absolute) addressing. That is, the segment will reside somewhere in core memory outside the zero page. "zeropage" (8 bit) means that 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.
Please note that a segment cannot have two different address sizes. A segment specified as zeropage cannot be declared as being absolute later.
Examples:
.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
.SETCPU
Switch the CPU instruction set. The command is followed by a string that
specifies the CPU. Possible values are those that can also be supplied to
the
--cpu
command line option,
namely: 6502, 6502X, 65SC02, 65C02, 65816, sunplus and HuC6280. Please
note that support for the sunplus CPU is not available in the freeware
version, because the instruction set of the sunplus CPU is "proprietary
and confidential".
See:
.CPU
,
.IFP02
,
.IFP816
,
.IFPC02
,
.IFPSC02
,
.P02
,
.P816
,
.PC02
,
.PSC02
.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 do the following:
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.RTS
instruction by RTL
if it is
used within a procedure declared as far
, or if the procedure has
no explicit address specification, but it is far
because of the
memory model used.Example:
.smart ; Be smart
.smart - ; Stop being smart
.STRUCT
Starts a struct definition. Structs are covered in a separate section named "Structs and unions".
See:
.ENDSTRUCT
.SUNPLUS
Enable the SunPlus instructions set. This command will not work in the freeware version of the assembler, because the instruction set is "proprietary and confidential".
See:
.P02
,
.PSC02
,
.PC02
, and
.P816
.TAG
Allocate space for a struct or union.
Example:
.struct Point
xcoord .word
ycoord .word
.endstruct
.bss
.tag Point ; Allocate 4 bytes
.WARNING
Force an assembly warning. The assembler will output a warning message
preceded 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, $AF13, _Clear
.ZEROPAGE
Switch to the ZEROPAGE segment and mark it as direct (zeropage) segment. The name of the ZEROPAGE segment is always "ZEROPAGE", so this is a shortcut for
.segment "ZEROPAGE", zeropage
Because of the "zeropage" attribute, labels declared in this segment are addressed using direct addressing mode if possible. You must instruct the linker to place this segment somewhere in the address range 0..$FF otherwise you will get errors.
See:
.SEGMENT