1 <!doctype linuxdoc system>
4 <title>ca65 Users Guide
5 <author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
6 <date>19.07.2000, 29.11.2000, 02.10.2001
9 ca65 is a powerful macro assembler for the 6502, 65C02 and 65816 CPUs. It is
10 used as a companion assembler for the cc65 crosscompiler, but it may also be
11 used as a standalone product.
14 <!-- Table of contents -->
17 <!-- Begin the document -->
21 ca65 is a replacement for the ra65 assembler that was part of the cc65 C
22 compiler, originally developed by John R. Dunning. I had some problems with
23 ra65 and the copyright does not permit some things which I wanted to be
24 possible, so I decided to write a completely new assembler/linker/archiver
25 suite for the cc65 compiler. ca65 is part of this suite.
27 Some parts of the assembler (code generation and some routines for symbol
28 table handling) are taken from an older crossassembler named a816 written
29 by me a long time ago.
32 <sect1>Design criteria<p>
34 Here's a list of the design criteria, that I considered important for the
39 <item> The assembler must support macros. Macros are not essential, but they
40 make some things easier, especially when you use the assembler in the
41 backend of a compiler.
42 <item> The assembler must support the newer 65C02 and 65816 CPUs. I have been
43 thinking about a 65816 backend for the C compiler, and even my old
44 a816 assembler had support for these CPUs, so this wasn't really a
46 <item> The assembler must produce relocatable code. This is necessary for the
47 compiler support, and it is more convenient.
48 <item> Conditional assembly must be supported. This is a must for bigger
49 projects written in assembler (like Elite128).
50 <item> The assembler must support segments, and it must support more than
51 three segments (this is the count, most other assemblers support).
52 Having more than one code segments helps developing code for systems
53 with a divided ROM area (like the C64).
54 <item> The linker must be able to resolve arbitrary expressions. It should
55 be able to get things like
62 <item> True lexical nesting for symbols. This is very convenient for larger
64 <item> "Cheap" local symbols without lexical nesting for those quick, late
66 <item> I liked the idea of "options" as Anre Fachats .o65 format has it, so I
67 introduced the concept into the object file format use by the new cc65
69 <item> The assembler will be a one pass assembler. There was no real need for
70 this decision, but I've written several multipass assemblers, and it
71 started to get boring. A one pass assembler needs much more elaborated
72 data structures, and because of that it's much more fun:-)
73 <item> Non-GPLed code that may be used in any project without restrictions or
74 fear of "GPL infecting" other code.
82 <sect1>Command line option overview<p>
84 The assembler accepts the following options:
87 ---------------------------------------------------------------------------
88 Usage: ca65 [options] file
90 -D name[=value] Define a symbol
91 -I dir Set an include directory search path
92 -U Mark unresolved symbols as import
93 -V Print the assembler version
94 -W n Set warning level n
95 -g Add debug info to object file
97 -i Ignore case of symbols
98 -l Create a listing if assembly was ok
99 -o name Name the output file
101 -t sys Set the target system
102 -v Increase verbosity
105 --auto-import Mark unresolved symbols as import
106 --cpu type Set cpu type
107 --debug-info Add debug info to object file
108 --feature name Set an emulation feature
109 --help Help (this text)
110 --ignore-case Ignore case of symbols
111 --include-dir dir Set an include directory search path
112 --listing Create a listing if assembly was ok
113 --pagelength n Set the page length for the listing
114 --smart Enable smart mode
115 --target sys Set the target system
116 --verbose Increase verbosity
117 --version Print the assembler version
118 ---------------------------------------------------------------------------
122 <sect1>Command line options in detail<p>
124 Here is a description of all the command line options:
128 <tag><tt>--cpu type</tt></tag>
130 Set the default for the CPU type. The option takes a parameter, which
133 6502, 65C02, 65816 and sunplus
135 The latter (sunplus) is not available in the freeware version, because the
136 instruction set of the sunplus CPU is "confidential".
139 <label id="option--feature">
140 <tag><tt>--feature name</tt></tag>
142 Enable an emulation feature. This is identical as using <tt/.FEATURE/
143 in the source with two exceptions: Feature names must be lower case, and
144 each feature must be specified by using an extra <tt/--feature/ option,
145 comma separated lists are not allowed.
147 See the discussion of the <tt><ref id=".FEATURE" name=".FEATURE"></tt>
148 command for a list of emulation features.
151 <label id="option-g">
152 <tag><tt>-g, --debug-info</tt></tag>
154 When this option (or the equivalent control command <tt/.DEBUGINFO/) is
155 used, the assembler will add a section to the object file that contains
156 all symbols (including local ones) together with the symbol values and
157 source file positions. The linker will put these additional symbols into
158 the VICE label file, so even local symbols can be seen in the VICE
162 <tag><tt>-h, --help</tt></tag>
164 Print the short option summary shown above.
167 <tag><tt>-i, --ignore-case</tt></tag>
169 This option makes the assembler case insensitive on identifiers and labels.
170 This option will override the default, but may itself be overriden by the
171 <tt><ref id=".CASE" name=".CASE"></tt> control command.
174 <tag><tt>-l, --listing</tt></tag>
176 Generate an assembler listing. The listing file will always have the
177 name of the main input file with the extension replaced by ".lst". This
178 may change in future versions.
181 <tag><tt>-o name</tt></tag>
183 The default output name is the name of the input file with the extension
184 replaced by ".o". If you don't like that, you may give another name with
185 the -o option. The output file will be placed in the same directory as
186 the source file, or, if -o is given, the full path in this name is used.
189 <tag><tt>--pagelength n</tt></tag>
191 sets the length of a listing page in lines. See the <tt><ref
192 id=".PAGELENGTH" name=".PAGELENGTH"></tt> directive for more information.
195 <tag><tt>-s, --smart-mode</tt></tag>
197 In smart mode (enabled by -s or the <tt><ref id=".SMART" name=".SMART"></tt>
198 pseudo instruction) the assembler will track usage of the <tt/REP/ and
199 <tt/SEP/ instructions in 65816 mode and update the operand sizes
200 accordingly. If the operand of such an instruction cannot be evaluated by
201 the assembler (for example, because the operand is an imported symbol), a
204 Beware: Since the assembler cannot trace the execution flow this may
205 lead to false results in some cases. If in doubt, use the .ixx and .axx
206 instructions to tell the assembler about the current settings. Smart
207 mode is off by default.
210 <label id="option-t">
211 <tag><tt>-t sys, --target sys</tt></tag>
213 Set the target system. This will enable translation of character strings
214 and character constants into the character set of the target platform.
215 The default for the target system is "none", which means that no translation
216 will take place. The assembler supports the same target systems as the
217 compiler, see there for a list.
220 <tag><tt>-v, --verbose</tt></tag>
222 Increase the assembler verbosity. Usually only needed for debugging
223 purposes. You may use this option more than one time for even more
227 <tag><tt>-D</tt></tag>
229 This option allows you to define symbols on the command line. Without a
230 value, the symbol is defined with the value zero. When giving a value,
231 you may use the '$' prefix for hexadecimal symbols. Please note
232 that for some operating systems, '$' has a special meaning, so
233 you may have to quote the expression.
236 <tag><tt>-I dir, --include-dir dir</tt></tag>
238 Name a directory which is searched for include files. The option may be
239 used more than once to specify more than one directory to search. The
240 current directory is always searched first before considering any
241 additional directores.
244 <tag><tt>-U, --auto-import</tt></tag>
246 Mark symbols that are not defined in the sources as imported symbols. This
247 should be used with care since it delays error messages about typos and such
248 until the linker is run. The compiler uses the equivalent of this switch
249 (<tt><ref id=".AUTOIMPORT" name=".AUTOIMPORT"></tt>) to enable auto imported
250 symbols for the runtime library. However, the compiler is supposed to
251 generate code that runs through the assembler without problems, something
252 which is not always true for assembler programmers.
255 <tag><tt>-V, --version</tt></tag>
257 Print the version number of the assembler. If you send any suggestions
258 or bugfixes, please include the version number.
261 <label id="option-W">
262 <tag><tt>-Wn</tt></tag>
264 Set the warning level for the assembler. Using -W2 the assembler will
265 even warn about such things like unused imported symbols. The default
266 warning level is 1, and it would probably be silly to set it to
273 <sect>Input format<p>
275 The assembler accepts the standard 6502/65816 assembler syntax. One line may
276 contain a label (which is identified by a colon), and, in addition to the
277 label, an assembler mnemonic, a macro, or a control command (see section <ref
278 id="control-commands" name="Control Commands"> for supported control
279 commands). Alternatively, the line may contain a symbol definition using the
280 '=' token. Everything after a semicolon is handled as a comment (that is, it
283 Here are some examples for valid input lines:
286 Label: ; A label and a comment
287 lda #$20 ; A 6502 instruction plus comment
288 L1: ldx #$20 ; Same with label
289 L2: .byte "Hello world" ; Label plus control command
290 mymac $20 ; Macro expansion
291 MySym = 3*L1 ; Symbol definition
292 MaSym = Label ; Another symbol
295 The assembler accepts all valid 6502 mnemonics when in 6502 mode (the
296 default). The assembler accepts all valid 65SC02 mnemonics when in 65SC02 mode
297 (after a <tt><ref id=".PC02" name=".PC02"></tt> command is found). The
298 assembler accepts all valid 65816 mnemonics with a few exceptions after a
299 .P816 command is found. These exceptions are listed below.
301 In 65816 mode several aliases are accepted in addition to the official
305 BGE is an alias for BCS
306 BLT is an alias for BCC
307 CPA is an alias for CMP
308 DEA is an alias for DEC A
309 INA is an alias for INC A
310 SWA is an alias for XBA
311 TAD is an alias for TCD
312 TAS is an alias for TCS
313 TDA is an alias for TDC
314 TSA is an alias for TSC
317 Evaluation of banked expressions in 65816 mode differs slightly from the
320 Instead of accepting a 24 bit address (something that is difficult for
321 the assembler to determine and would have required one more special
322 .import command), the bank and the absolute address in that bank are
326 jsl 3.$1234 ; Call subroutine at $1234 in bank 3
329 For literal values, the assembler accepts the widely used number formats:
330 A preceeding '$' denotes a hex value, a preceeding '%' denotes a
331 binary value, and a bare number is interpeted as a decimal. There are
332 currently no octal values and no floats.
339 <sect1>Expression evaluation<p>
341 All expressions are evaluated with (at least) 32 bit precision. An
342 expression may contain constant values and any combination of internal and
343 external symbols. Expressions that cannot be evaluated at assembly time
344 are stored inside the object file for evaluation by the linker.
345 Expressions referencing imported symbols must always be evaluated by the
349 <sect1>Size of an expressions result<p>
351 Sometimes, the assembler must know about the size of the value that is the
352 result of an expression. This is usually the case, if a decision has to be
353 made, to generate a zero page or an absolute memory references. In this
354 case, the assembler has to make some assumptions about the result of an
358 <item> If the result of an expression is constant, the actual value is
359 checked to see if it's a byte sized expression or not.
360 <item> If the expression is explicitly casted to a byte sized expression by
361 one of the '>'/'<' operators, it is a byte expression.
362 <item> If this is not the case, and the expression contains a symbol,
363 explicitly declared as zero page symbol (by one of the .importzp or
364 .exportzp instructions), then the whole expression is assumed to be
366 <item> If the expression contains symbols that are not defined, and these
367 symbols are local symbols, the enclosing scopes are searched for a
368 symbol with the same name. If one exists and this symbol is defined,
369 it's attributes are used to determine the result size.
370 <item> In all other cases the expression is assumed to be word sized.
373 Note: If the assembler is not able to evaluate the expression at assembly
374 time, the linker will evaluate it and check for range errors as soon as
378 <sect1>Boolean expressions<p>
380 In the context of a boolean expression, any non zero value is evaluated as
381 true, any other value to false. The result of a boolean expression is 1 if
382 it's true, and zero if it's false. There are boolean operators with extrem
383 low precedence with version 2.x (where x > 0). The <tt/.AND/ and <tt/.OR/
384 operators are shortcut operators. That is, if the result of the expression is
385 already known, after evaluating the left hand side, the right hand side is
389 <sect1>Available operators<p>
391 Available operators sorted by precedence:
394 Op Description Precedence
395 -------------------------------------------------------------------
396 .CONCAT Builtin function 0
397 .LEFT Builtin function 0
398 .MID Builtin function 0
399 .RIGHT Builtin function 0
400 .STRING Builtin function 0
402 * Builtin pseudo variable (r/o) 1
403 .BLANK Builtin function 1
404 .CONST Builtin function 1
405 .CPU Builtin pseudo variable (r/o) 1
406 .DEFINED Builtin function 1
407 .MATCH Builtin function 1
408 .TCOUNT Builtin function 1
409 .XMATCH Builtin function 1
410 .PARAMCOUNT Builtin pseudo variable (r/o) 1
411 .REFERENCED Builtin function 1
412 :: Global namespace override 1
415 ~ Unary bitwise not 1
416 .BITNOT Unary bitwise not 1
417 < Low byte operator 1
418 > High byte operator 1
422 .MOD Modulo operation 2
424 .BITAND Bitwise and 2
426 .BITXOR Bitwise xor 2
427 << Shift left operator 2
428 .SHL Shift left operator 2
429 >> Shift right operator
430 .SHR Shift right operator 2
437 = Compare operation (equal) 4
438 <> Compare operation (not equal) 4
439 < Compare operation (less) 4
440 > Compare operation (greater) 4
441 <= Compare operation (less or equal) 4
442 >= Compare operation (greater or equal) 4
444 && Boolean and 5
456 To force a specific order of evaluation, braces may be used as usual.
458 Some of the pseudo variables mentioned above need some more explanation:
461 * This symbol is replaced by the value of the program
462 counter at start of the current instruction. Note, that
463 '*' yields a rvalue, that means, you cannot assign to it.
464 Use <tt/.ORG/ to set the program counter in sections with
471 <sect>Symbols and labels<p>
473 The assembler allows you to use symbols instead of naked values to make
474 the source more readable. There are a lot of different ways to define and
475 use symbols and labels, giving a lot of flexibility.
478 <sect1>Numeric constants<p>
480 Numeric constants are defined using the equal sign. After doing
486 may use the symbol "two" in every place where a number is expected, and it is
487 evaluated to the value 2 in this context. An example would be
494 <sect1>Standard labels<p>
496 A label is defined by writing the name of the label at the start of the line
497 (before any instruction mnemonic, macro or pseudo directive), followed by a
498 colon. This will declare a symbol with the given name and the value of the
499 current program counter.
502 <sect1>Local labels and symbols<p>
504 Using the <tt><ref id=".PROC" name=".PROC"></tt> directive, it is possible to
505 create regions of code where the names of labels and symbols are local to this
506 region. They are not known outside of this region and cannot be accessed from
507 there. Such regions may be nested like PROCEDUREs in Pascal.
509 See the description of the <tt><ref id=".PROC" name=".PROC"></tt>
510 directive for more information.
513 <sect1>Cheap local labels<p>
515 Cheap local labels are defined like standard labels, but the name of the
516 label must begin with a special symbol (usually '@', but this can be
517 changed by the <tt><ref id=".LOCALCHAR" name=".LOCALCHAR"></tt>
520 Cheap local labels are visible only between two non cheap labels. As soon as a
521 standard symbol is encountered (this may also be a local symbol if inside a
522 region defined with the <tt><ref id=".PROC" name=".PROC"></tt> directive), the
523 cheap local symbol goes out of scope.
525 You may use cheap local labels as an easy way to reuse common label
526 names like "Loop". Here is an example:
529 Clear: lda #$00 ; Global label
531 @Loop: sta Mem,y ; Local label
535 Sub: ... ; New global label
536 bne @Loop ; ERROR: Unknown identifier!
539 <sect1>Unnamed labels<p>
541 If you really want to write messy code, there are also unnamed
542 labels. These labels do not have a name (you guessed that already,
543 didn't you?). A colon is used to mark the absence of the name.
545 Unnamed labels may be accessed by using the colon plus several minus
546 or plus characters as a label designator. Using the '-' characters
547 will create a back reference (use the n'th label backwards), using
548 '+' will create a forward reference (use the n'th label in forward
549 direction). An example will help to understand this:
571 As you can see from the example, unnamed labels will make even short
572 sections of code hard to understand, because you have to count labels
573 to find branch targets (this is the reason why I for my part do
574 prefer the "cheap" local labels). Nevertheless, unnamed labels are
575 convenient in some situations, so it's your decision.
578 <sect1>Using macros to define labels and constants<p>
580 While there are drawbacks with this approach, it may be handy in some
581 situations. Using <tt><ref id=".DEFINE" name=".DEFINE"></tt>, it is
582 possible to define symbols or constants that may be used elsewhere. Since
583 the macro facility works on a very low level, there is no scoping. On the
584 other side, you may also define string constants this way (this is not
585 possible with the other symbol types).
591 .DEFINE version "SOS V2.3"
593 four = two * two ; Ok
596 .PROC ; Start local scope
597 two = 3 ; Will give "2 = 3" - invalid!
602 <sect1>Symbols and <tt>.DEBUGINFO</tt><p>
604 If <tt><ref id=".DEBUGINFO" name=".DEBUGINFO"></tt> is enabled (or <ref
605 id="option-g" name="-g"> is given on the command line), global, local and
606 cheap local labels are written to the object file and will be available in the
607 symbol file via the linker. Unnamed labels are not written to the object file,
608 because they don't have a name which would allow to access them.
612 <sect>Control commands<label id="control-commands">
615 Here's a list of all control commands and a description, what they do:
618 <sect1><tt>.A16</tt><label id=".A16"><p>
620 Valid only in 65816 mode. Switch the accumulator to 16 bit.
622 Note: This command will not emit any code, it will tell the assembler to
623 create 16 bit operands for immediate accumulator adressing mode.
625 See also: <tt><ref id=".SMART" name=".SMART"></tt>
628 <sect1><tt>.A8</tt><label id=".A8"><p>
630 Valid only in 65816 mode. Switch the accumulator to 8 bit.
632 Note: This command will not emit any code, it will tell the assembler to
633 create 8 bit operands for immediate accu adressing mode.
635 See also: <tt><ref id=".SMART" name=".SMART"></tt>
638 <sect1><tt>.ADDR</tt><label id=".ADDR"><p>
640 Define word sized data. In 6502 mode, this is an alias for <tt/.WORD/ and
641 may be used for better readability if the data words are address values. In
642 65816 mode, the address is forced to be 16 bit wide to fit into the current
643 segment. See also <tt><ref id=".FARADDR" name=".FARADDR"></tt>. The command
644 must be followed by a sequence of (not necessarily constant) expressions.
649 .addr $0D00, $AF13, _Clear
652 See: <tt><ref id=".FARADDR" name=".FARADDR"></tt>, <tt><ref id=".WORD"
656 <sect1><tt>.ALIGN</tt><label id=".ALIGN"><p>
658 Align data to a given boundary. The command expects a constant integer
659 argument that must be a power of two, plus an optional second argument
660 in byte range. If there is a second argument, it is used as fill value,
661 otherwise the value defined in the linker configuration file is used
662 (the default for this value is zero).
664 Since alignment depends on the base address of the module, you must
665 give the same (or a greater) alignment for the segment when linking.
666 The linker will give you a warning, if you don't do that.
675 <sect1><tt>.ASCIIZ</tt><label id=".ASCIIZ"><p>
677 Define a string with a trailing zero.
682 Msg: .asciiz "Hello world"
685 This will put the string "Hello world" followed by a binary zero into
686 the current segment. There may be more strings separated by commas, but
687 the binary zero is only appended once (after the last one).
690 <sect1><tt>.AUTOIMPORT</tt><label id=".AUTOIMPORT"><p>
692 Is followed by a plus or a minus character. When switched on (using a
693 +), undefined symbols are automatically marked as import instead of
694 giving errors. When switched off (which is the default so this does not
695 make much sense), this does not happen and an error message is
696 displayed. The state of the autoimport flag is evaluated when the
697 complete source was translated, before outputing actual code, so it is
698 <em/not/ possible to switch this feature on or off for separate sections
699 of code. The last setting is used for all symbols.
701 You should probably not use this switch because it delays error
702 messages about undefined symbols until the link stage. The cc65
703 compiler (which is supposed to produce correct assembler code in all
704 circumstances, something which is not true for most assembler
705 programmers) will insert this command to avoid importing each and every
706 routine from the runtime library.
711 .autoimport + ; Switch on auto import
715 <sect1><tt>.BLANK</tt><label id=".BLANK"><p>
717 Builtin function. The function evaluates its argument in braces and
718 yields "false" if the argument is non blank (there is an argument), and
719 "true" if there is no argument. As an example, the <tt/.IFBLANK/ statement
727 <sect1><tt>.BSS</tt><label id=".BSS"><p>
729 Switch to the BSS segment. The name of the BSS segment is always "BSS",
730 so this is a shortcut for
736 See also the <tt><ref id=".SEGMENT" name=".SEGMENT"></tt> command.
739 <sect1><tt>.BYT, .BYTE</tt><label id=".BYTE"><p>
741 Define byte sized data. Must be followed by a sequence of (byte ranged)
742 expressions or strings.
748 .byt "world", $0D, $00
752 <sect1><tt>.CASE</tt><label id=".CASE"><p>
754 Switch on or off case sensitivity on identifiers. The default is off
755 (that is, identifiers are case sensitive), but may be changed by the
756 -i switch on the command line.
757 The command must be followed by a '+' or '-' character to switch the
758 option on or off respectively.
763 .case - ; Identifiers are not case sensitive
767 <sect1><tt>.CODE</tt><label id=".CODE"><p>
769 Switch to the CODE segment. The name of the CODE segment is always
770 "CODE", so this is a shortcut for
776 See also the <tt><ref id=".SEGMENT" name=".SEGMENT"></tt> command.
779 <sect1><tt>.CONDES</tt><label id=".CONDES"><p>
781 Export a symbol and mark it in a special way. The linker is able to build
782 tables of all such symbols. This may be used to automatically create a list
783 of functions needed to initialize linked library modules.
785 Note: The linker has a feature to build a table of marked routines, but it
786 is your code that must call these routines, so just declaring a symbol with
787 <tt/.CONDES/ does nothing by itself.
789 All symbols are exported as an absolute (16 bit) symbol. You don't need to
790 use an additional <tt><ref id=".EXPORT" name=".EXPORT"></tt> statement, this
791 is implied by <tt/.CONDES/.
793 <tt/.CONDES/ is followed by the type, which may be <tt/constructor/,
794 <tt/destructor/ or a numeric value between 0 and 6 (where 0 is the same as
795 specifiying <tt/constructor/ and 1 is equal to specifying <tt/destructor/).
796 The <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
797 id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> commands are actually shortcuts
798 for <tt/.CONDES/ with a type of <tt/constructor/ resp. <tt/destructor/.
800 After the type, an optional priority may be specified. If no priority is
801 given, the default priority of 7 is used. Be careful when assigning
802 priorities to your own module constructors so they won't interfere with the
803 ones in the cc65 library.
808 .condes ModuleInit, constructor
809 .condes ModInit, 0, 16
812 See the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
813 id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> commands and the separate section
814 <ref id="condes" name="Module constructors/destructors"> explaining the
815 feature in more detail.
818 <sect1><tt>.CONCAT</tt><label id=".CONCAT"><p>
820 Builtin function. The function allows to concatenate a list of string
821 constants separated by commas. The result is a string constant that
822 is the concatentation of all arguments. This function is most useful
823 in macros and when used together with the <tt/.STRING/ builtin function.
824 The function may be used in any case where a string constant is
830 .include .concat ("myheader", ".", "inc")
833 This is the same as the command
836 .include "myheader.inc"
840 <sect1><tt>.CONST</tt><label id=".CONST"><p>
842 Builtin function. The function evaluates its argument in braces and
843 yields "true" if the argument is a constant expression (that is, an
844 expression that yields a constant value at assembly time) and "false"
845 otherwise. As an example, the .IFCONST statement may be replaced by
852 <sect1><tt>.CONSTRUCTOR</tt><label id=".CONSTRUCTOR"><p>
854 Export a symbol and mark it as a module constructor. This may be used
855 together with the linker to build a table of constructor subroutines that
856 are called by the startup code.
858 Note: The linker has a feature to build a table of marked routines, but it
859 is your code that must call these routines, so just declaring a symbol as
860 constructor does nothing by itself.
862 A constructor is always exported as an absolute (16 bit) symbol. You don't
863 need to use an additional <tt/.export/ statement, this is implied by
864 <tt/.constructor/. It may have an optional priority that is separated by a
865 comma. If no priority is given, the default priority of 7 is used. Be
866 careful when assigning priorities to your own module constructors so they
867 won't interfere with the ones in the cc65 library.
872 .constructor ModuleInit
873 .constructor ModInit, 16
876 See the <tt><ref id=".CONDES" name=".CONDES"></tt> and <tt><ref
877 id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> commands and the separate section
878 <ref id="condes" name="Module constructors/destructors"> explaining the
879 feature in more detail.
882 <sect1><tt>.CPU</tt><label id=".CPU"><p>
884 Reading this pseudo variable will give a constant integer value that
885 tells which instruction set is currently enabled. Possible values are:
894 It may be used to replace the .IFPxx pseudo instructions or to construct
895 even more complex expressions.
900 .if (.cpu = 0) .or (.cpu = 1)
912 <sect1><tt>.DATA</tt><label id=".DATA"><p>
914 Switch to the DATA segment. The name of the DATA segment is always
915 "DATA", so this is a shortcut for
921 See also the <tt><ref id=".SEGMENT" name=".SEGMENT"></tt> command.
924 <sect1><tt>.DBYT</tt><label id=".DBYT"><p>
926 Define word sized data with the hi and lo bytes swapped (use <tt/.WORD/ to
927 create word sized data in native 65XX format). Must be followed by a
928 sequence of (word ranged) expressions.
936 This will emit the bytes
942 into the current segment in that order.
945 <sect1><tt>.DEBUGINFO</tt><label id=".DEBUGINFO"><p>
947 Switch on or off debug info generation. The default is off (that is,
948 the object file will not contain debug infos), but may be changed by the
949 -g switch on the command line.
950 The command must be followed by a '+' or '-' character to switch the
951 option on or off respectively.
956 .debuginfo + ; Generate debug info
960 <sect1><tt>.DEFINE</tt><label id=".DEFINE"><p>
962 Start a define style macro definition. The command is followed by an
963 identifier (the macro name) and optionally by a list of formal arguments
965 See section <ref id="macros" name="Macros">.
968 <sect1><tt>.DEF, .DEFINED</tt><label id=".DEFINED"><p>
970 Builtin function. The function expects an identifier as argument in braces.
971 The argument is evaluated, and the function yields "true" if the identifier
972 is a symbol that is already defined somewhere in the source file up to the
973 current position. Otherwise the function yields false. As an example, the
974 <tt><ref id=".IFDEF" name=".IFDEF"></tt> statement may be replaced by
981 <sect1><tt>.DESTRUCTOR</tt><label id=".DESTRUCTOR"><p>
983 Export a symbol and mark it as a module destructor. This may be used
984 together with the linker to build a table of destructor subroutines that
985 are called by the startup code.
987 Note: The linker has a feature to build a table of marked routines, but it
988 is your code that must call these routines, so just declaring a symbol as
989 constructor does nothing by itself.
991 A destructor is always exported as an absolute (16 bit) symbol. You don't
992 need to use an additional <tt/.export/ statement, this is implied by
993 <tt/.destructor/. It may have an optional priority that is separated by a
994 comma. If no priority is given, the default priority of 7 is used. Be
995 careful when assigning priorities to your own module destructors so they
996 won't interfere with the ones in the cc65 library.
1001 .destructor ModuleDone
1002 .destructor ModDone, 16
1005 See the <tt><ref id=".CONDES" name=".CONDES"></tt> and <tt><ref
1006 id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> commands and the separate
1007 section <ref id="condes" name="Module constructors/destructors"> explaining
1008 the feature in more detail.
1011 <sect1><tt>.DWORD</tt><label id=".DWORD"><p>
1013 Define dword sized data (4 bytes) Must be followed by a sequence of
1019 .dword $12344512, $12FA489
1023 <sect1><tt>.ELSE</tt><label id=".ELSE"><p>
1025 Conditional assembly: Reverse the current condition.
1028 <sect1><tt>.ELSEIF</tt><label id=".ELSEIF"><p>
1030 Conditional assembly: Reverse current condition and test a new one.
1033 <sect1><tt>.END</tt><label id=".END"><p>
1035 Forced end of assembly. Assembly stops at this point, even if the command
1036 is read from an include file.
1039 <sect1><tt>.ENDIF</tt><label id=".ENDIF"><p>
1041 Conditional assembly: Close a <tt><ref id=".IF" name=".IF..."></tt> or
1042 <tt><ref id=".ELSE" name=".ELSE"></tt> branch.
1045 <sect1><tt>.ENDMAC, .ENDMACRO</tt><label id=".ENDMACRO"><p>
1047 End of macro definition (see section <ref id="macros" name="Macros">).
1050 <sect1><tt>.ENDPROC</tt><label id=".ENDPROC"><p>
1052 End of local lexical level (see <tt><ref id=".PROC" name=".PROC"></tt>).
1055 <sect1><tt>.ENDREP, .ENDREPEAT</tt><label id=".ENDREPEAT"><p>
1057 End a <tt><ref id=".REPEAT" name=".REPEAT"></tt> block.
1060 <sect1><tt>.ERROR</tt><label id=".ERROR"><p>
1062 Force an assembly error. The assembler will output an error message
1063 preceeded by "User error" and will <em/not/ produce an object file.
1065 This command may be used to check for initial conditions that must be
1066 set before assembling a source file.
1076 .error "Must define foo or bar!"
1080 See also the <tt><ref id=".WARNING" name=".WARNING"></tt> and <tt><ref
1081 id=".OUT" name=".OUT"></tt> directives.
1084 <sect1><tt>.EXITMAC, .EXITMACRO</tt><label id=".EXITMACRO"><p>
1086 Abort a macro expansion immidiately. This command is often useful in
1087 recursive macros. See separate section <ref id="macros" name="Macros">.
1090 <sect1><tt>.EXPORT</tt><label id=".EXPORT"><p>
1092 Make symbols accessible from other modules. Must be followed by a comma
1093 separated list of symbols to export.
1101 See: <tt><ref id=".EXPORTZP" name=".EXPORTZP"></tt>
1104 <sect1><tt>.EXPORTZP</tt><label id=".EXPORTZP"><p>
1106 Make symbols accessible from other modules. Must be followed by a comma
1107 separated list of symbols to export. The exported symbols are explicitly
1108 marked as zero page symols.
1116 See: <tt><ref id=".EXPORT" name=".EXPORT"></tt>
1119 <sect1><tt>.FARADDR</tt><label id=".FARADDR"><p>
1121 Define far (24 bit) address data. The command must be followed by a
1122 sequence of (not necessarily constant) expressions.
1127 .faraddr DrawCircle, DrawRectangle, DrawHexagon
1130 See: <tt><ref id=".ADDR" name=".ADDR"></tt>
1133 <sect1><tt>.FEATURE</tt><label id=".FEATURE"><p>
1135 This directive may be used to enable one or more compatibility features
1136 of the assembler. While the use of <tt/.FEATURE/ should be avoided when
1137 possible, it may be useful when porting sources written for other
1138 assemblers. There is no way to switch a feature off, once you have
1139 enabled it, so using
1145 will enable the feature until end of assembly is reached.
1147 The following features are available:
1151 <tag><tt>dollar_is_pc</tt></tag>
1153 The dollar sign may be used as an alias for the star (`*'), which
1154 gives the value of the current PC in expressions.
1155 Note: Assignment to the pseudo variable is not allowed.
1157 <tag><tt>labels_without_colons</tt></tag>
1159 Allow labels without a trailing colon. These labels are only accepted,
1160 if they start at the beginning of a line (no leading white space).
1162 <tag><tt>loose_string_term</tt></tag>
1164 Accept single quotes as well as double quotes as terminators for string
1167 <tag><tt>loose_char_term</tt></tag>
1169 Accept single quotes as well as double quotes as terminators for char
1172 <tag><tt>at_in_identifiers</tt></tag>
1174 Accept the at character (`@') as a valid character in identifiers. The
1175 at character is not allowed to start an identifier, even with this
1178 <tag><tt>dollar_in_identifiers</tt></tag>
1180 Accept the dollar sign (`$') as a valid character in identifiers. The
1181 at character is not allowed to start an identifier, even with this
1184 <tag><tt>leading_dot_in_identifiers</tt></tag>
1186 Accept the dot (`.') as the first character of an identifier. This may be
1187 used for example to create macro names that start with a dot emulating
1188 control directives of other assemblers. Note however, that none of the
1189 reserved keywords built into the assembler, that starts with a dot, may be
1190 overridden. When using this feature, you may also get into trouble if
1191 later versions of the assembler define new keywords starting with a dot.
1193 <tag><tt>pc_assignment</tt></tag>
1195 Allow assignments to the PC symbol (`*' or `$' if <tt/dollar_is_pc/
1196 is enabled). Such an assignment is handled identical to the <tt><ref
1197 id=".ORG" name=".ORG"></tt> command (which is usually not needed, so just
1198 removing the lines with the assignments may also be an option when porting
1199 code written for older assemblers).
1203 It is also possible to specify features on the command line using the
1204 <tt><ref id="option--feature" name="--feature"></tt> command line option.
1205 This is useful when translating sources written for older assemblers, when
1206 you don't want to change the source code.
1208 As an example, to translate sources written for Andre Fachats xa65
1209 assembler, the features
1212 labels_without_colons, pc_assignment, loose_char_term
1215 may be helpful. They do not make ca65 completely compatible, so you may not
1216 be able to translate the sources without changes, even when enabling these
1217 features. However, I have found several sources that translate without
1218 problems when enabling these features on the command line.
1221 <sect1><tt>.FILEOPT, .FOPT</tt><label id=".FOPT"><p>
1223 Insert an option string into the object file. There are two forms of
1224 this command, one specifies the option by a keyword, the second
1225 specifies it as a number. Since usage of the second one needs knowledge
1226 of the internal encoding, its use is not recommended and I will only
1227 describe the first form here.
1229 The command is followed by one of the keywords
1237 a comma and a string. The option is written into the object file
1238 together with the string value. This is currently unidirectional and
1239 there is no way to actually use these options once they are in the
1245 .fileopt comment, "Code stolen from my brother"
1246 .fileopt compiler, "BASIC 2.0"
1247 .fopt author, "J. R. User"
1251 <sect1><tt>.GLOBAL</tt><label id=".GLOBAL"><p>
1253 Declare symbols as global. Must be followed by a comma separated list of
1254 symbols to declare. Symbols from the list, that are defined somewhere in the
1255 source, are exported, all others are imported. Additional <tt><ref
1256 id=".IMPORT" name=".IMPORT"></tt> or <tt><ref id=".EXPORT"
1257 name=".EXPORT"></tt> commands for the same symbol are allowed.
1266 <sect1><tt>.GLOBALZP</tt><label id=".GLOBALZP"><p>
1268 Declare symbols as global. Must be followed by a comma separated list of
1269 symbols to declare. Symbols from the list, that are defined somewhere in the
1270 source, are exported, all others are imported. Additional <tt><ref
1271 id=".IMPORTZP" name=".IMPORTZP"></tt> or <tt><ref id=".EXPORTZP"
1272 name=".EXPORTZP"></tt> commands for the same symbol are allowed. The symbols
1273 in the list are explicitly marked as zero page symols.
1282 <sect1><tt>.I16</tt><label id=".I16"><p>
1284 Valid only in 65816 mode. Switch the index registers to 16 bit.
1286 Note: This command will not emit any code, it will tell the assembler to
1287 create 16 bit operands for immediate operands.
1289 See also the <tt><ref id=".I8" name=".I8"></tt> and <tt><ref id=".SMART"
1290 name=".SMART"></tt> commands.
1293 <sect1><tt>.I8</tt><label id=".I8"><p>
1295 Valid only in 65816 mode. Switch the index registers to 8 bit.
1297 Note: This command will not emit any code, it will tell the assembler to
1298 create 8 bit operands for immediate operands.
1300 See also the <tt><ref id=".I16" name=".I16"></tt> and <tt><ref id=".SMART"
1301 name=".SMART"></tt> commands.
1304 <sect1><tt>.IF</tt><label id=".IF"><p>
1306 Conditional assembly: Evalute an expression and switch assembler output
1307 on or off depending on the expression. The expression must be a constant
1308 expression, that is, all operands must be defined.
1310 A expression value of zero evaluates to FALSE, any other value evaluates
1314 <sect1><tt>.IFBLANK</tt><label id=".IFBLANK"><p>
1316 Conditional assembly: Check if there are any remaining tokens in this line,
1317 and evaluate to FALSE if this is the case, and to TRUE otherwise. If the
1318 condition is not true, further lines are not assembled until an <tt><ref
1319 id=".ELSE" name=".ESLE"></tt>, <tt><ref id=".ELSEIF" name=".ELSEIF"></tt> or
1320 <tt><ref id=".ENDIF" name=".ENDIF"></tt> directive.
1322 This command is often used to check if a macro parameter was given. Since an
1323 empty macro parameter will evaluate to nothing, the condition will evaluate
1324 to FALSE if an empty parameter was given.
1338 See also: <tt><ref id=".BLANK" name=".BLANK"></tt>
1341 <sect1><tt>.IFCONST</tt><label id=".IFCONST"><p>
1343 Conditional assembly: Evaluate an expression and switch assembler output
1344 on or off depending on the constness of the expression.
1346 A const expression evaluates to to TRUE, a non const expression (one
1347 containing an imported or currently undefined symbol) evaluates to
1350 See also: <tt><ref id=".CONST" name=".CONST"></tt>
1353 <sect1><tt>.IFDEF</tt><label id=".IFDEF"><p>
1355 Conditional assembly: Check if a symbol is defined. Must be followed by
1356 a symbol name. The condition is true if the the given symbol is already
1357 defined, and false otherwise.
1359 See also: <tt><ref id=".DEFINED" name=".DEFINED"></tt>
1362 <sect1><tt>.IFNBLANK</tt><label id=".IFNBLANK"><p>
1364 Conditional assembly: Check if there are any remaining tokens in this line,
1365 and evaluate to TRUE if this is the case, and to FALSE otherwise. If the
1366 condition is not true, further lines are not assembled until an <tt><ref
1367 id=".ELSE" name=".ELSE"></tt>, <tt><ref id=".ELSEIF" name=".ELSEIF"></tt> or
1368 <tt><ref id=".ENDIF" name=".ENDIF"></tt> directive.
1370 This command is often used to check if a macro parameter was given.
1371 Since an empty macro parameter will evaluate to nothing, the condition
1372 will evaluate to FALSE if an empty parameter was given.
1385 See also: <tt><ref id=".BLANK" name=".BLANK"></tt>
1388 <sect1><tt>.IFNDEF</tt><label id=".IFNDEF"><p>
1390 Conditional assembly: Check if a symbol is defined. Must be followed by
1391 a symbol name. The condition is true if the the given symbol is not
1392 defined, and false otherwise.
1394 See also: <tt><ref id=".DEFINED" name=".DEFINED"></tt>
1397 <sect1><tt>.IFNREF</tt><label id=".IFNREF"><p>
1399 Conditional assembly: Check if a symbol is referenced. Must be followed
1400 by a symbol name. The condition is true if if the the given symbol was
1401 not referenced before, and false otherwise.
1403 See also: <tt><ref id=".REFERENCED" name=".REFERENCED"></tt>
1406 <sect1><tt>.IFP02</tt><label id=".IFP02"><p>
1408 Conditional assembly: Check if the assembler is currently in 6502 mode
1409 (see <tt><ref id=".P02" name=".P02"></tt> command).
1412 <sect1><tt>.IFP816</tt><label id=".IFP816"><p>
1414 Conditional assembly: Check if the assembler is currently in 65816 mode
1415 (see <tt><ref id=".P816" name=".P816"></tt> command).
1418 <sect1><tt>.IFPC02</tt><label id=".IFPC02"><p>
1420 Conditional assembly: Check if the assembler is currently in 65C02 mode
1421 (see <tt><ref id=".PC02" name=".PC02"></tt> command).
1424 <sect1><tt>.IFREF</tt><label id=".IFREF"><p>
1426 Conditional assembly: Check if a symbol is referenced. Must be followed
1427 by a symbol name. The condition is true if if the the given symbol was
1428 referenced before, and false otherwise.
1430 This command may be used to build subroutine libraries in include files
1431 (you may use separate object modules for this purpose too).
1436 .ifref ToHex ; If someone used this subroutine
1437 ToHex: tay ; Define subroutine
1443 See also: <tt><ref id=".REFERENCED" name=".REFERENCED"></tt>
1446 <sect1><tt>.IMPORT</tt><label id=".IMPORT"><p>
1448 Import a symbol from another module. The command is followed by a comma
1449 separated list of symbols to import.
1457 See: <tt><ref id=".IMPORTZP" name=".IMPORTZP"></tt>
1460 <sect1><tt>.IMPORTZP</tt><label id=".IMPORTZP"><p>
1462 Import a symbol from another module. The command is followed by a comma
1463 separated list of symbols to import. The symbols are explicitly imported
1464 as zero page symbols (that is, symbols with values in byte range).
1472 See: <tt><ref id=".IMPORT" name=".IMPORT"></tt>
1475 <sect1><tt>.INCBIN</tt><label id=".INCBIN"><p>
1477 Include a file as binary data. The command expects a string argument
1478 that is the name of a file to include literally in the current segment.
1479 In addition to that, a start offset and a size value may be specified,
1480 separated by commas. If no size is specified, all of the file from the
1481 start offset to end-of-file is used. If no start position is specified
1482 either, zero is assume (which means that the whole file is inserted).
1487 ; Include whole file
1488 .incbin "sprites.dat"
1490 ; Include file starting at offset 256
1491 .incbin "music.dat", $100
1493 ; Read 100 bytes starting at offset 200
1494 .incbin "graphics.dat", 200, 100
1498 <sect1><tt>.INCLUDE</tt><label id=".INCLUDE"><p>
1500 Include another file. Include files may be nested up to a depth of 16.
1509 <sect1><tt>.LEFT</tt><label id=".LEFT"><p>
1511 Builtin function. Extracts the left part of a given token list.
1516 .LEFT (<int expr>, <token list>)
1519 The first integer expression gives the number of tokens to extract from
1520 the token list. The second argument is the token list itself.
1524 To check in a macro if the given argument has a '#' as first token
1525 (immidiate addressing mode), use something like this:
1530 .if (.match (.left (1, arg), #))
1532 ; ldax called with immidiate operand
1540 See also the <tt><ref id=".MID" name=".MID"></tt> and <tt><ref id=".RIGHT"
1541 name=".RIGHT"></tt> builtin functions.
1544 <sect1><tt>.LINECONT</tt><label id=".LINECONT"><p>
1546 Switch on or off line continuations using the backslash character
1547 before a newline. The option is off by default.
1548 Note: Line continuations do not work in a comment. A backslash at the
1549 end of a comment is treated as part of the comment and does not trigger
1551 The command must be followed by a '+' or '-' character to switch the
1552 option on or off respectively.
1557 .linecont + ; Allow line continuations
1560 #$20 ; This is legal now
1564 <sect1><tt>.LIST</tt><label id=".LIST"><p>
1566 Enable output to the listing. The command must be followed by a boolean
1567 switch ("on", "off", "+" or "-") and will enable or disable listing
1569 The option has no effect if the listing is not enabled by the command line
1570 switch -l. If -l is used, an internal counter is set to 1. Lines are output
1571 to the listing file, if the counter is greater than zero, and suppressed if
1572 the counter is zero. Each use of <tt/.LIST/ will increment or decrement the
1578 .list on ; Enable listing output
1582 <sect1><tt>.LISTBYTES</tt><label id=".LISTBYTES"><p>
1584 Set, how many bytes are shown in the listing for one source line. The
1585 default is 12, so the listing will show only the first 12 bytes for any
1586 source line that generates more than 12 bytes of code or data.
1587 The directive needs an argument, which is either "unlimited", or an
1588 integer constant in the range 4..255.
1593 .listbytes unlimited ; List all bytes
1594 .listbytes 12 ; List the first 12 bytes
1595 .incbin "data.bin" ; Include large binary file
1599 <sect1><tt>.LOCAL</tt><label id=".LOCAL"><p>
1601 This command may only be used inside a macro definition. It declares a
1602 list of identifiers as local to the macro expansion.
1604 A problem when using macros are labels: Since they don't change their name,
1605 you get a "duplicate symbol" error if the macro is expanded the second time.
1606 Labels declared with <tt><ref id=".LOCAL" name=".LOCAL"></tt> have their
1607 name mapped to an internal unique name (<tt/___ABCD__/) with each macro
1610 Some other assemblers start a new lexical block inside a macro expansion.
1611 This has some drawbacks however, since that will not allow <em/any/ symbol
1612 to be visible outside a macro, a feature that is sometimes useful. The
1613 <tt><ref id=".LOCAL" name=".LOCAL"></tt> command is in my eyes a better way
1614 to address the problem.
1616 You get an error when using <tt><ref id=".LOCAL" name=".LOCAL"></tt> outside
1620 <sect1><tt>.LOCALCHAR</tt><label id=".LOCALCHAR"><p>
1622 Defines the character that start "cheap" local labels. You may use one
1623 of '@' and '?' as start character. The default is '@'.
1625 Cheap local labels are labels that are visible only between two non
1626 cheap labels. This way you can reuse identifiers like "<tt/loop/" without
1627 using explicit lexical nesting.
1634 Clear: lda #$00 ; Global label
1635 ?Loop: sta Mem,y ; Local label
1639 Sub: ... ; New global label
1640 bne ?Loop ; ERROR: Unknown identifier!
1644 <sect1><tt>.MACPACK</tt><label id=".MACPACK"><p>
1646 Insert a predefined macro package. The command is followed by an
1647 identifier specifying the macro package to insert. Available macro
1651 generic Defines generic macros like add and sub.
1652 longbranch Defines conditional long jump macros.
1655 Including a macro package twice, or including a macro package that
1656 redefines already existing macros will lead to an error.
1661 .macpack longbranch ; Include macro package
1663 cmp #$20 ; Set condition codes
1664 jne Label ; Jump long on condition
1667 Macro packages are explained in more detail in section <ref
1668 id="macropackages" name="Macro packages">).
1671 <sect1><tt>.MAC, .MACRO</tt><label id=".MAC"><p>
1673 Start a classic macro definition. The command is followed by an identifier
1674 (the macro name) and optionally by a comma separated list of identifiers
1675 that are macro parameters.
1677 See section <ref id="macros" name="Macros">.
1680 <sect1><tt>.MATCH</tt><label id=".MATCH"><p>
1682 Builtin function. Matches two token lists against each other. This is
1683 most useful within macros, since macros are not stored as strings, but
1689 .MATCH(<token list #1>, <token list #2>)
1692 Both token list may contain arbitrary tokens with the exception of the
1693 terminator token (comma resp. right parenthesis) and
1700 Often a macro parameter is used for any of the token lists.
1702 Please note that the function does only compare tokens, not token
1703 attributes. So any number is equal to any other number, regardless of the
1704 actual value. The same is true for strings. If you need to compare tokens
1705 <em/and/ token attributes, use the <tt><ref id=".XMATCH"
1706 name=".XMATCH"></tt> function.
1710 Assume the macro <tt/ASR/, that will shift right the accumulator by one,
1711 while honoring the sign bit. The builtin processor instructions will allow
1712 an optional "A" for accu addressing for instructions like <tt/ROL/ and
1713 <tt/ROR/. We will use the <tt><ref id=".MATCH" name=".MATCH"></tt> function
1714 to check for this and print and error for invalid calls.
1719 .if (.not .blank(arg)) .and (.not .match (arg, a))
1720 .error "Syntax error"
1723 cmp #$80 ; Bit 7 into carry
1724 lsr a ; Shift carry into bit 7
1729 The macro will only accept no arguments, or one argument that must be the
1730 reserved keyword "A".
1732 See: <tt><ref id=".XMATCH" name=".XMATCH"></tt>
1735 <sect1><tt>.MID</tt><label id=".MID"><p>
1737 Builtin function. Takes a starting index, a count and a token list as
1738 arguments. Will return part of the token list.
1743 .MID (<int expr>, <int expr>, <token list>)
1746 The first integer expression gives the starting token in the list (the
1747 first token has index 0). The second integer expression gives the number
1748 of tokens to extract from the token list. The third argument is the
1753 To check in a macro if the given argument has a '<tt/#/' as first token
1754 (immidiate addressing mode), use something like this:
1759 .if (.match (.mid (0, 1, arg), #))
1761 ; ldax called with immidiate operand
1769 See also the <tt><ref id=".LEFT" name=".LEFT"></tt> and <tt><ref id=".RIGHT"
1770 name=".RIGHT"></tt> builtin functions.
1773 <sect1><tt>.ORG</tt><label id=".ORG"><p>
1775 Start a section of absolute code. The command is followed by a constant
1776 expression that gives the new PC counter location for which the code is
1777 assembled. Use <tt><ref id=".RELOC" name=".RELOC"></tt> to switch back to
1780 Please note that you <em/do not need/ this command in most cases. Placing
1781 code at a specific address is the job of the linker, not the assembler, so
1782 there is usually no reason to assemble code to a specific address.
1784 You may not switch segments while inside a section of absolute code.
1789 .org $7FF ; Emit code starting at $7FF
1793 <sect1><tt>.OUT</tt><label id=".OUT"><p>
1795 Output a string to the console without producing an error. This command
1796 is similiar to <tt/.ERROR/, however, it does not force an assembler error
1797 that prevents the creation of an object file.
1802 .out "This code was written by the codebuster(tm)"
1805 See also the <tt><ref id=".WARNING" name=".WARNING"></tt> and <tt><ref
1806 id=".ERROR" name=".ERROR"></tt> directives.
1809 <sect1><tt>.P02</tt><label id=".P02"><p>
1811 Enable the 6502 instruction set, disable 65C02 and 65816 instructions.
1812 This is the default if not overridden by the <tt/--cpu/ command line
1815 See: <tt><ref id=".PC02" name=".PC02"></tt> and <tt><ref id=".P816"
1819 <sect1><tt>.P816</tt><label id=".P816"><p>
1821 Enable the 65816 instruction set. This is a superset of the 65C02 and
1822 6502 instruction sets.
1824 See: <tt><ref id=".P02" name=".P02"></tt> and <tt><ref id=".PC02"
1828 <sect1><tt>.PAGELEN, .PAGELENGTH</tt><label id=".PAGELENGTH"><p>
1830 Set the page length for the listing. Must be followed by an integer
1831 constant. The value may be "unlimited", or in the range 32 to 127. The
1832 statement has no effect if no listing is generated. The default value is -1
1833 (unlimited) but may be overridden by the <tt/--pagelength/ command line
1834 option. Beware: Since ca65 is a one pass assembler, the listing is generated
1835 after assembly is complete, you cannot use multiple line lengths with one
1836 source. Instead, the value set with the last <tt/.PAGELENGTH/ is used.
1841 .pagelength 66 ; Use 66 lines per listing page
1843 .pagelength unlimited ; Unlimited page length
1847 <sect1><tt>.PARAMCOUNT</tt><label id=".PARAMCOUNT"><p>
1849 This builtin pseudo variable is only available in macros. It is replaced by
1850 the actual number of parameters that were given in the macro invocation.
1855 .macro foo arg1, arg2, arg3
1856 .if .paramcount <> 3
1857 .error "Too few parameters for macro foo"
1863 See section <ref id="macros" name="Macros">.
1866 <sect1><tt>.PC02</tt><label id=".PC02"><p>
1868 Enable the 65C02 instructions set. This instruction set includes all
1871 See: <tt><ref id=".P02" name=".P02"></tt> and <tt><ref id=".P816"
1875 <sect1><tt>.PROC</tt><label id=".PROC"><p>
1877 Start a nested lexical level. All new symbols from now on are in the local
1878 lexical level and are not accessible from outside. Symbols defined outside
1879 this local level may be accessed as long as their names are not used for new
1880 symbols inside the level. Symbols names in other lexical levels do not
1881 clash, so you may use the same names for identifiers. The lexical level ends
1882 when the <tt><ref id=".ENDPROC" name=".ENDPROC"></tt> command is read.
1883 Lexical levels may be nested up to a depth of 16.
1885 The command may be followed by an identifier, in this case the
1886 identifier is declared in the outer level as a label having the value of
1887 the program counter at the start of the lexical level.
1889 Note: Macro names are always in the global level and in a separate name
1890 space. There is no special reason for this, it's just that I've never
1891 had any need for local macro definitions.
1896 .proc Clear ; Define Clear subroutine, start new level
1898 L1: sta Mem,y ; L1 is local and does not cause a
1899 ; duplicate symbol error if used in other
1902 bne L1 ; Reference local symbol
1904 .endproc ; Leave lexical level
1907 See: <tt><ref id=".ENDPROC" name=".ENDPROC"></tt>
1910 <sect1><tt>.REF, .REFERENCED</tt><label id=".REFERENCED"><p>
1912 Builtin function. The function expects an identifier as argument in braces.
1913 The argument is evaluated, and the function yields "true" if the identifier
1914 is a symbol that has already been referenced somewhere in the source file up
1915 to the current position. Otherwise the function yields false. As an example,
1916 the <tt><ref id=".IFREF" name=".IFREF"></tt> statement may be replaced by
1922 See: <tt><ref id=".DEFINED" name=".DEFINED"></tt>
1925 <sect1><tt>.REPEAT</tt><label id=".REPEAT"><p>
1927 Repeat all commands between <tt/.REPEAT/ and <tt><ref id=".ENDREPEAT"
1928 name=".ENDREPEAT"></tt> constant number of times. The command is followed by
1929 a constant expression that tells how many times the commands in the body
1930 should get repeated. Optionally, a comma and an identifier may be specified.
1931 If this identifier is found in the body of the repeat statement, it is
1932 replaced by the current repeat count (starting with zero for the first time
1933 the body is repeated).
1935 <tt/.REPEAT/ statements may be nested. If you use the same repeat count
1936 identifier for a nested <tt/.REPEAT/ statement, the one from the inner
1937 level will be used, not the one from the outer level.
1941 The following macro will emit a string that is "encrypted" in that all
1942 characters of the string are XORed by the value $55.
1946 .repeat .strlen(Arg), I
1947 .byte .strat(Arg, I) .xor $55
1952 See: <tt><ref id=".ENDREPEAT" name=".ENDREPEAT"></tt>
1955 <sect1><tt>.RELOC</tt><label id=".RELOC"><p>
1957 Switch back to relocatable mode. See the <tt><ref id=".ORG"
1958 name=".ORG"></tt> command.
1961 <sect1><tt>.RES</tt><label id=".RES"><p>
1963 Reserve storage. The command is followed by one or two constant
1964 expressions. The first one is mandatory and defines, how many bytes of
1965 storage should be defined. The second, optional expression must by a
1966 constant byte value that will be used as value of the data. If there
1967 is no fill value given, the linker will use the value defined in the
1968 linker configuration file (default: zero).
1973 ; Reserve 12 bytes of memory with value $AA
1978 <sect1><tt>.RIGHT</tt><label id=".RIGHT"><p>
1980 Builtin function. Extracts the right part of a given token list.
1985 .RIGHT (<int expr>, <token list>)
1988 The first integer expression gives the number of tokens to extract from
1989 the token list. The second argument is the token list itself.
1991 See also the <tt><ref id=".LEFT" name=".LEFT"></tt> and <tt><ref id=".MID"
1992 name=".MID"></tt> builtin functions.
1995 <sect1><tt>.RODATA</tt><label id=".RODATA"><p>
1997 Switch to the RODATA segment. The name of the RODATA segment is always
1998 "RODATA", so this is a shortcut for
2004 The RODATA segment is a segment that is used by the compiler for
2005 readonly data like string constants.
2007 See also the <tt><ref id=".SEGMENT" name=".SEGMENT"></tt> command.
2010 <sect1><tt>.SEGMENT</tt><label id=".SEGMENT"><p>
2012 Switch to another segment. Code and data is always emitted into a
2013 segment, that is, a named section of data. The default segment is
2014 "CODE". There may be up to 254 different segments per object file
2015 (and up to 65534 per executable). There are shortcut commands for
2016 the most common segments ("CODE", "DATA" and "BSS").
2018 The command is followed by a string containing the segment name (there
2019 are some constraints for the name - as a rule of thumb use only those
2020 segment names that would also be valid identifiers). There may also be
2021 an optional attribute separated by a comma. Valid attributes are
2022 "<tt/zeropage/" and "<tt/absolute/".
2024 When specifying a segment for the first time, "absolute" is the
2025 default. For all other uses, the attribute specified the first time
2028 "absolute" means that this is a segment with absolute addressing. That
2029 is, the segment will reside somewhere in core memory outside the zero
2030 page. "zeropage" means the opposite: The segment will be placed in the
2031 zero page and direct (short) addressing is possible for data in this
2034 Beware: Only labels in a segment with the zeropage attribute are marked
2035 as reachable by short addressing. The `*' (PC counter) operator will
2036 work as in other segments and will create absolute variable values.
2041 .segment "ROM2" ; Switch to ROM2 segment
2042 .segment "ZP2", zeropage ; New direct segment
2043 .segment "ZP2" ; Ok, will use last attribute
2044 .segment "ZP2", absolute ; Error, redecl mismatch
2047 See: <tt><ref id=".BSS" name=".BSS"></tt>, <tt><ref id=".CODE"
2048 name=".CODE"></tt>, <tt><ref id=".DATA" name=".DATA"></tt> and <tt><ref
2049 id=".RODATA" name=".RODATA"></tt>
2052 <sect1><tt>.SMART</tt><label id=".SMART"><p>
2054 Switch on or off smart mode. The command must be followed by a '+' or
2055 '-' character to switch the option on or off respectively. The default
2056 is off (that is, the assembler doesn't try to be smart), but this
2057 default may be changed by the -s switch on the command line.
2059 In smart mode the assembler will track usage of the <tt/REP/ and <tt/SEP/
2060 instructions in 65816 mode and update the operand sizes accordingly. If
2061 the operand of such an instruction cannot be evaluated by the assembler
2062 (for example, because the operand is an imported symbol), a warning is
2063 issued. Beware: Since the assembler cannot trace the execution flow this
2064 may lead to false results in some cases. If in doubt, use the <tt/.Inn/ and
2065 <tt/.Ann/ instructions to tell the assembler about the current settings.
2071 .smart - ; Stop being smart
2075 <sect1><tt>.STRAT</tt><label id=".STRAT"><p>
2077 Builtin function. The function accepts a string and an index as
2078 arguments and returns the value of the character at the given position
2079 as an integer value. The index is zero based.
2085 ; Check if the argument string starts with '#'
2086 .if (.strat (Arg, 0) = '#')
2093 <sect1><tt>.STRING</tt><label id=".STRING"><p>
2095 Builtin function. The function accepts an argument in braces and converts
2096 this argument into a string constant. The argument may be an identifier, or
2097 a constant numeric value.
2099 Since you can use a string in the first place, the use of the function may
2100 not be obvious. However, it is useful in macros, or more complex setups.
2105 ; Emulate other assemblers:
2107 .segment .string(name)
2112 <sect1><tt>.STRLEN</tt><label id=".STRLEN"><p>
2114 Builtin function. The function accepts a string argument in braces and
2115 eveluates to the length of the string.
2119 The following macro encodes a string as a pascal style string with
2120 a leading length byte.
2124 .byte .strlen(Arg), Arg
2129 <sect1><tt>.TCOUNT</tt><label id=".TCOUNT"><p>
2131 Builtin function. The function accepts a token list in braces. The
2132 function result is the number of tokens given as argument.
2136 The <tt/ldax/ macro accepts the '#' token to denote immidiate addressing (as
2137 with the normal 6502 instructions). To translate it into two separate 8 bit
2138 load instructions, the '#' token has to get stripped from the argument:
2142 .if (.match (.mid (0, 1, arg), #))
2143 ; ldax called with immidiate operand
2144 lda #<(.right (.tcount (arg)-1, arg))
2145 ldx #>(.right (.tcount (arg)-1, arg))
2153 <sect1><tt>.WARNING</tt><label id=".WARNING"><p>
2155 Force an assembly warning. The assembler will output a warning message
2156 preceeded by "User warning". This warning will always be output, even if
2157 other warnings are disabled with the <tt><ref id="option-W" name="-W0"></tt>
2158 command line option.
2160 This command may be used to output possible problems when assembling
2169 .warning "Forward jump in jne, cannot optimize!"
2179 See also the <tt><ref id=".ERROR" name=".ERROR"></tt> and <tt><ref id=".OUT"
2180 name=".OUT"></tt> directives.
2183 <sect1><tt>.WORD</tt><label id=".WORD"><p>
2185 Define word sized data. Must be followed by a sequence of (word ranged,
2186 but not necessarily constant) expressions.
2191 .word $0D00, $AF13, _Clear
2195 <sect1><tt>.XMATCH</tt><label id=".XMATCH"><p>
2197 Builtin function. Matches two token lists against each other. This is
2198 most useful within macros, since macros are not stored as strings, but
2204 .XMATCH(<token list #1>, <token list #2>)
2207 Both token list may contain arbitrary tokens with the exception of the
2208 terminator token (comma resp. right parenthesis) and
2215 Often a macro parameter is used for any of the token lists.
2217 The function compares tokens <em/and/ token values. If you need a function
2218 that just compares the type of tokens, have a look at the <tt><ref
2219 id=".MATCH" name=".MATCH"></tt> function.
2221 See: <tt><ref id=".MATCH" name=".MATCH"></tt>
2224 <sect1><tt>.ZEROPAGE</tt><label id=".ZEROPAGE"><p>
2226 Switch to the ZEROPAGE segment and mark it as direct (zeropage) segment.
2227 The name of the ZEROPAGE segment is always "ZEROPAGE", so this is a
2231 .segment "ZEROPAGE", zeropage
2234 Because of the "zeropage" attribute, labels declared in this segment are
2235 addressed using direct addressing mode if possible. You <em/must/ instruct
2236 the linker to place this segment somewhere in the address range 0..$FF
2237 otherwise you will get errors.
2239 See: <tt><ref id=".SEGMENT" name=".SEGMENT"></tt>
2243 <sect>Macros<label id="macros"><p>
2246 <sect1>Introduction<p>
2248 Macros may be thought of as "parametrized super instructions". Macros are
2249 sequences of tokens that have a name. If that name is used in the source
2250 file, the macro is "expanded", that is, it is replaced by the tokens that
2251 were specified when the macro was defined.
2254 <sect1>Macros without parameters<p>
2256 In it's simplest form, a macro does not have parameters. Here's an
2260 .macro asr ; Arithmetic shift right
2261 cmp #$80 ; Put bit 7 into carry
2262 ror ; Rotate right with carry
2266 The macro above consists of two real instructions, that are inserted into
2267 the code, whenever the macro is expanded. Macro expansion is simply done
2268 by using the name, like this:
2277 <sect1>Parametrized macros<p>
2279 When using macro parameters, macros can be even more useful:
2293 When calling the macro, you may give a parameter, and each occurence of
2294 the name "addr" in the macro definition will be replaced by the given
2313 A macro may have more than one parameter, in this case, the parameters
2314 are separated by commas. You are free to give less parameters than the
2315 macro actually takes in the definition. You may also leave intermediate
2316 parameters empty. Empty parameters are replaced by empty space (that is,
2317 they are removed when the macro is exanded). If you have a look at our
2318 macro definition above, you will see, that replacing the "addr" parameter
2319 by nothing will lead to wrong code in most lines. To help you, writing
2320 macros with a variable parameter list, there are some control commands:
2322 <tt><ref id=".IFBLANK" name=".IFBLANK"></tt> tests the rest of the line and
2323 returns true, if there are any tokens on the remainder of the line. Since
2324 empty parameters are replaced by nothing, this may be used to test if a given
2325 parameter is empty. <tt><ref id=".IFNBLANK" name=".IFNBLANK"></tt> tests the
2328 Look at this example:
2331 .macro ldaxy a, x, y
2344 This macro may be called as follows:
2347 ldaxy 1, 2, 3 ; Load all three registers
2349 ldaxy 1, , 3 ; Load only a and y
2351 ldaxy , , 3 ; Load y only
2354 There's another helper command for determining, which macro parameters are
2355 valid: <tt><ref id=".PARAMCOUNT" name=".PARAMCOUNT"></tt> This command is
2356 replaced by the parameter count given, <em/including/ intermediate empty macro
2360 ldaxy 1 ; .PARAMCOUNT = 1
2361 ldaxy 1,,3 ; .PARAMCOUNT = 3
2362 ldaxy 1,2 ; .PARAMCOUNT = 2
2363 ldaxy 1, ; .PARAMCOUNT = 2
2364 ldaxy 1,2,3 ; .PARAMCOUNT = 3
2368 <sect1>Recursive macros<p>
2370 Macros may be used recursively:
2373 .macro push r1, r2, r3
2382 There's also a special macro to help writing recursive macros: <tt><ref
2383 id=".EXITMACRO" name=".EXITMACRO"></tt> This command will stop macro expansion
2387 .macro push r1, r2, r3, r4, r5, r6, r7
2389 ; First parameter is empty
2395 push r2, r3, r4, r5, r6, r7
2399 When expanding this macro, the expansion will push all given parameters
2400 until an empty one is encountered. The macro may be called like this:
2403 push $20, $21, $32 ; Push 3 ZP locations
2404 push $21 ; Push one ZP location
2408 <sect1>Local symbols inside macros<p>
2410 Now, with recursive macros, <tt><ref id=".IFBLANK" name=".IFBLANK"></tt> and
2411 <tt><ref id=".PARAMCOUNT" name=".PARAMCOUNT"></tt>, what else do you need?
2412 Have a look at the inc16 macro above. Here is it again:
2426 If you have a closer look at the code, you will notice, that it could be
2427 written more efficiently, like this:
2438 But imagine what happens, if you use this macro twice? Since the label
2439 "Skip" has the same name both times, you get a "duplicate symbol" error.
2440 Without a way to circumvent this problem, macros are not as useful, as
2441 they could be. One solution is, to start a new lexical block inside the
2455 Now the label is local to the block and not visible outside. However,
2456 sometimes you want a label inside the macro to be visible outside. To make
2457 that possible, there's a new command that's only usable inside a macro
2458 definition: <tt><ref id=".LOCAL" name=".LOCAL"></tt>. <tt/.LOCAL/ declares one
2459 or more symbols as local to the macro expansion. The names of local variables
2460 are replaced by a unique name in each separate macro expansion. So we could
2461 also solve the problem above by using <tt/.LOCAL/:
2465 .local Skip ; Make Skip a local symbol
2472 Skip: ; Not visible outside
2477 <sect1>C style macros<p>
2479 Starting with version 2.5 of the assembler, there is a second macro type
2480 available: C style macros using the <tt/.DEFINE/ directive. These macros are
2481 similar to the classic macro type described above, but behaviour is sometimes
2486 <item> Macros defined with <tt><ref id=".DEFINE" name=".DEFINE"></tt> may not
2487 span more than a line. You may use line continuation (see <tt><ref
2488 id=".LINECONT" name=".LINECONT"></tt>) to spread the definition over
2489 more than one line for increased readability, but the macro itself
2490 may not contain an end-of-line token.
2492 <item> Macros defined with <tt><ref id=".DEFINE" name=".DEFINE"></tt> share
2493 the name space with classic macros, but they are detected and replaced
2494 at the scanner level. While classic macros may be used in every place,
2495 where a mnemonic or other directive is allowed, <tt><ref id=".DEFINE"
2496 name=".DEFINE"></tt> style macros are allowed anywhere in a line. So
2497 they are more versatile in some situations.
2499 <item> <tt><ref id=".DEFINE" name=".DEFINE"></tt> style macros may take
2500 parameters. While classic macros may have empty parameters, this is
2501 not true for <tt><ref id=".DEFINE" name=".DEFINE"></tt> style macros.
2502 For this macro type, the number of actual parameters must match
2503 exactly the number of formal parameters.
2505 To make this possible, formal parameters are enclosed in braces when
2506 defining the macro. If there are no parameters, the empty braces may
2509 <item> Since <tt><ref id=".DEFINE" name=".DEFINE"></tt> style macros may not
2510 contain end-of-line tokens, there are things that cannot be done. They
2511 may not contain several processor instructions for example. So, while
2512 some things may be done with both macro types, each type has special
2513 usages. The types complement each other.
2517 Let's look at a few examples to make the advantages and disadvantages
2520 To emulate assemblers that use "<tt/EQU/" instead of "<tt/=/" you may use the
2521 following <tt/.DEFINE/:
2526 foo EQU $1234 ; This is accepted now
2529 You may use the directive to define string constants used elsewhere:
2532 ; Define the version number
2533 .define VERSION "12.3a"
2539 Macros with parameters may also be useful:
2542 .define DEBUG(message) .out message
2544 DEBUG "Assembling include file #3"
2547 Note that, while formal parameters have to be placed in braces, this is
2548 not true for the actual parameters. Beware: Since the assembler cannot
2549 detect the end of one parameter, only the first token is used. If you
2550 don't like that, use classic macros instead:
2558 (This is an example where a problem can be solved with both macro types).
2561 <sect1>Characters in macros<p>
2563 When using the <ref id="option-t" name="-t"> option, characters are translated
2564 into the target character set of the specific machine. However, this happens
2565 as late as possible. This means that strings are translated if they are part
2566 of a <tt><ref id=".BYTE" name=".BYTE"></tt> or <tt><ref id=".ASCIIZ"
2567 name=".ASCIIZ"></tt> command. Characters are translated as soon as they are
2568 used as part of an expression.
2570 This behaviour is very intuitive outside of macros but may be confusing when
2571 doing more complex macros. If you compare characters against numeric values,
2572 be sure to take the translation into account.
2577 <sect>Macro packages<label id="macropackages"><p>
2579 Using the <tt><ref id=".MACPACK" name=".MACPACK"></tt> directive, predefined
2580 macro packages may be included with just one command. Available macro packages
2584 <sect1><tt>.MACPACK generic</tt><p>
2586 This macro package defines macros that are useful in almost any program.
2587 Currently, two macros are defined:
2602 <sect1><tt>.MACPACK longbranch</tt><p>
2604 This macro package defines long conditional jumps. They are named like the
2605 short counterpart but with the 'b' replaced by a 'j'. Here is a sample
2606 definition for the "<tt/jeq/" macro, the other macros are built using the same
2611 .if .def(Target) .and ((*+2)-(Target) <= 127)
2620 All macros expand to a short branch, if the label is already defined (back
2621 jump) and is reachable with a short jump. Otherwise the macro expands to a
2622 conditional branch with the branch condition inverted, followed by an absolute
2623 jump to the actual branch target.
2625 The package defines the following macros:
2628 jeq, jne, jmi, jpl, jcs, jcc, jvs, jvc
2633 <sect>Module constructors/destructors<label id="condes"><p>
2635 <em>Note:</em> This section applies mostly to C programs, so the explanation
2636 below uses examples from the C libraries. However, the feature may also be
2637 useful for assembler programs.
2640 <sect1>Module overview<p>
2642 Using the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
2643 id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> keywords it it possible to export
2644 functions in a special way. The linker is able to generate tables with all
2645 functions of a specific type. Such a table will <em>only</em> include symbols
2646 from object files that are linked into a specific executable. This may be used
2647 to add initialization and cleanup code for library modules.
2649 The C heap functions are an example where module initialization code is used.
2650 All heap functions (<tt>malloc</tt>, <tt>free</tt>, ...) work with a few
2651 variables that contain the start and the end of the heap, pointers to the free
2652 list and so on. Since the end of the heap depends on the size and start of the
2653 stack, it must be initialized at runtime. However, initializing these
2654 variables for programs that do not use the heap are a waste of time and
2657 So the central module defines a function that contains initialization code and
2658 exports this function using the <tt/.CONSTRUCTOR/ statement. If (and only if)
2659 this module is added to an executable by the linker, the initialization
2660 function will be placed into the table of constructors by the linker. The C
2661 startup code will call all constructors before <tt/main/ and all destructors
2662 after <tt/main/, so without any further work, the heap initialization code is
2663 called once the module is linked in.
2665 While it would be possible to add explicit calls to initialization functions
2666 in the startup code, the new approach has several advantages:
2670 If a module is not included, the initialization code is not linked in and not
2671 called. So you don't pay for things you don't need.
2674 Adding another library that needs initialization does not mean that the
2675 startup code has to be changed. Before we had module constructors and
2676 destructors, the startup code for all systems had to be adjusted to call the
2677 new initialization code.
2680 The feature saves memory: Each additional initialization function needs just
2681 two bytes in the table (a pointer to the function).
2688 When creating and using module constructors and destructors, please take care
2694 The linker will only generate function tables, it will not generate code to
2695 call these functions. If you're using the feature in some other than the
2696 existing C environments, you have to write code to call all functions in a
2697 linker generated table yourself. See the <tt>condes</tt> module in the C
2698 runtime for an example on how to do this.
2701 The linker will only add addresses of functions that are in modules linked to
2702 the executable. This means that you have to be careful where to place the
2703 condes functions. If initialization is needed for a group of functions, be
2704 sure to place the initialization function into a module that is linked in
2705 regardless of which function is called by the user.
2708 The linker will generate the tables only when requested to do so by the
2709 <tt/FEATURE CONDES/ statement in the linker config file. Each table has to
2710 be requested separately.
2713 Constructors and destructors may have priorities. These priorities determine
2714 the order of the functions in the table. If your intialization or cleanup code
2715 does depend on other intiialization or cleanup code, you have to choose the
2716 priority for the functions accordingly.
2719 Besides the <tt><ref id=".CONSTRUCTOR" name=".CONSTRUCTOR"></tt> and <tt><ref
2720 id=".DESTRUCTOR" name=".DESTRUCTOR"></tt> statements, there is also a more
2721 generic command: <tt><ref id=".CONDES" name=".CONDES"></tt>. This allows to
2722 specify an additional type. Predefined types are 0 (constructor) and 1
2723 (destructor). The linker generates a separate table for each type on request.
2731 <sect>Bugs/Feedback<p>
2733 If you have problems using the assembler, if you find any bugs, or if
2734 you're doing something interesting with the assembler, I would be glad to
2735 hear from you. Feel free to contact me by email
2736 (<htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">).
2742 ca65 (and all cc65 binutils) are (C) Copyright 1998-2001 Ullrich von
2743 Bassewitz. For usage of the binaries and/or sources the following
2744 conditions do apply:
2746 This software is provided 'as-is', without any expressed or implied
2747 warranty. In no event will the authors be held liable for any damages
2748 arising from the use of this software.
2750 Permission is granted to anyone to use this software for any purpose,
2751 including commercial applications, and to alter it and redistribute it
2752 freely, subject to the following restrictions:
2755 <item> The origin of this software must not be misrepresented; you must not
2756 claim that you wrote the original software. If you use this software
2757 in a product, an acknowledgment in the product documentation would be
2758 appreciated but is not required.
2759 <item> Altered source versions must be plainly marked as such, and must not
2760 be misrepresented as being the original software.
2761 <item> This notice may not be removed or altered from any source
projects / cc65 / blob