1 <!doctype linuxdoc system>
4 <title>ld65 Users Guide
5 <author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
6 <date>02.12.2000, 02.10.2001
9 The ld65 linker combines object files into an executable file. ld65 is highly
10 configurable and uses configuration files for high flexibility.
13 <!-- Table of contents -->
16 <!-- Begin the document -->
20 The ld65 linker combines several object modules created by the ca65
21 assembler, producing an executable file. The object modules may be read
22 from a library created by the ar65 archiver (this is somewhat faster and
23 more convenient). The linker was designed to be as flexible as possible.
24 It complements the features that are built into the ca65 macroassembler:
28 <item> Accept any number of segments to form an executable module.
30 <item> Resolve arbitrary expressions stored in the object files.
32 <item> In case of errors, use the meta information stored in the object files
33 to produce helpful error messages. In case of undefined symbols,
34 expression range errors, or symbol type mismatches, ld65 is able to
35 tell you the exact location in the original assembler source, where
36 the symbol was referenced.
38 <item> Flexible output. The output of ld65 is highly configurable by a config
39 file. More common platforms are supported by builtin configurations
40 that may be activated by naming the target system. The output
41 generation was designed with different output formats in mind, so
42 adding other formats shouldn't be a great problem.
50 <sect1>Command line option overview<p>
52 The linker is called as follows:
55 ---------------------------------------------------------------------------
56 Usage: ld65 [options] module ...
58 -C name Use linker config file
59 -Ln name Create a VICE label file
60 -Lp Mark write protected segments as such (VICE)
61 -S addr Set the default start address
62 -V Print the linker version
64 -m name Create a map file
65 -o name Name the default output file
66 -t sys Set the target system
71 --config name Use linker config file
72 --help Help (this text)
73 --mapfile name Create a map file
74 --start-addr addr Set the default start address
75 --target sys Set the target system
76 --version Print the linker version
77 ---------------------------------------------------------------------------
81 <sect1>Command line options in detail<p>
83 Here is a description of all the command line options:
87 <tag><tt>-h, --help</tt></tag>
89 Print the short option summary shown above.
93 <tag><tt>-m name, --mapfile name</tt></tag>
95 This option (which needs an argument that will used as a filename for
96 the generated map file) will cause the linker to generate a map file.
97 The map file does contain a detailed overview over the modules used, the
98 sizes for the different segments, and a table containing exported
102 <label id="option-o">
103 <tag><tt>-o name</tt></tag>
105 The -o switch is used to give the name of the default output file.
106 Depending on your output configuration, this name may NOT be used as
107 name for the output file. However, for the builtin configurations, this
108 name is used for the output file name.
111 <label id="option-t">
112 <tag><tt>-t sys, --target sys</tt></tag>
114 The argument for the -t switch is the name of the target system. Since this
115 switch will activate a builtin configuration, it may not be used together
116 with the <tt><ref id="option-C" name="-C"></tt> option. The following target
117 systems are currently supported:
125 <item>cbm510 (CBM-II series with 40 column video)
126 <item>cbm610 (all CBM series-II computers with 80 column video)
127 <item>pet (all CBM PET systems except the 2001)
132 There are a few more targets defined but neither of them is actually
133 supported. See <ref id="builtin-configs" name="builtin configurations"> for
137 <label id="option-v">
138 <tag><tt>-v, --verbose</tt></tag>
140 Using the -v option, you may enable more output that may help you to
141 locate problems. If an undefined symbol is encountered, -v causes the
142 linker to print a detailed list of the references (that is, source file
143 and line) for this symbol.
146 <tag><tt>-vm</tt></tag>
148 Must be used in conjunction with <tt><ref id="option-m" name="-m"></tt>
149 (generate map file). Normally the map file will not include empty segments
150 and sections, or unreferenced symbols. Using this option, you can force the
151 linker to include all this information into the map file.
154 <label id="option-C">
155 <tag><tt>-C</tt></tag>
157 This gives the name of an output config file to use. See section 4 for more
158 information about config files. -C may not be used together with <tt><ref
159 id="option-t" name="-t"></tt>.
162 <tag><tt>-Ln</tt></tag>
164 This option allows you to create a file that contains all global labels and
165 may be loaded into VICE emulator using the <tt/ll/ (load label) command. You
166 may use this to debug your code with VICE. Note: Older versions had some
167 bugs in the label code. If you have problems, please get the latest VICE
171 <tag><tt>-Lp</tt></tag>
176 <label id="option-S">
177 <tag><tt>-S addr, --start-addr addr</tt></tag>
179 Using -S you may define the default starting address. If and how this
180 address is used depends on the config file in use. For the builtin
181 configurations, only the "none" system honors an explicit start address,
182 all other builtin config provide their own.
185 <tag><tt>-V, --version</tt></tag>
187 This option print the version number of the linker. If you send any
188 suggestions or bugfixes, please include this number.
192 If one of the modules is not found in the current directory, and the module
193 name does not have a path component, the value of the environment variable
194 <tt/CC65_LIB/ is prepended to the name, and the linker tries to open the
195 module with this new name.
199 <sect>Detailed workings<p>
201 The linker does several things when combining object modules:
203 First, the command line is parsed from left to right. For each object file
204 encountered (object files are recognized by a magic word in the header, so
205 the linker does not care about the name), imported and exported
206 identifiers are read from the file and inserted in a table. If a library
207 name is given (libraries are also recognized by a magic word, there are no
208 special naming conventions), all modules in the library are checked if an
209 export from this module would satisfy an import from other modules. All
210 modules where this is the case are marked. If duplicate identifiers are
211 found, the linker issues a warning.
213 This procedure (parsing and reading from left to right) does mean, that a
214 library may only satisfy references for object modules (given directly or from
215 a library) named <em/before/ that library. With the command line
218 ld65 crt0.o clib.lib test.o
221 the module test.o may not contain references to modules in the library
222 clib.lib. If this is the case, you have to change the order of the modules
226 ld65 crt0.o test.o clib.lib
229 Step two is, to read the configuration file, and assign start addresses
230 for the segments and define any linker symbols (see <ref id="config-files"
231 name="Configuration files">).
233 After that, the linker is ready to produce an output file. Before doing that,
234 it checks it's data for consistency. That is, it checks for unresolved
235 externals (if the output format is not relocatable) and for symbol type
236 mismatches (for example a zero page symbol is imported by a module as absolute
239 Step four is, to write the actual target files. In this step, the linker will
240 resolve any expressions contained in the segment data. Circular references are
241 also detected in this step (a symbol may have a circular reference that goes
242 unnoticed if the symbol is not used).
244 Step five is to output a map file with a detailed list of all modules,
245 segments and symbols encountered.
247 And, last step, if you give the <tt><ref id="option-v" name="-v"></tt> switch
248 twice, you get a dump of the segment data. However, this may be quite
249 unreadable if you're not a developer:-)
253 <sect>Configuration files<label id="config-files"><p>
255 Configuration files are used to describe the layout of the output file(s). Two
256 major topics are covered in a config file: The memory layout of the target
257 architecture, and the assignment of segments to memory areas. In addition,
258 several other attributes may be specified.
260 Case is ignored for keywords, that is, section or attribute names, but it is
261 <em/not/ ignored for names and strings.
265 <sect1>Memory areas<p>
267 Memory areas are specified in a <tt/MEMORY/ section. Lets have a look at an
268 example (this one describes the usable memory layout of the C64):
272 RAM1: start = $0800, size = $9800;
273 ROM1: start = $A000, size = $2000;
274 RAM2: start = $C000, size = $1000;
275 ROM2: start = $E000, size = $2000;
279 As you can see, there are two ram areas and two rom areas. The names
280 (before the colon) are arbitrary names that must start with a letter, with
281 the remaining characters being letters or digits. The names of the memory
282 areas are used when assigning segments. As mentioned above, case is
283 significant for these names.
285 The syntax above is used in all sections of the config file. The name
286 (<tt/ROM1/ etc.) is said to be an identifier, the remaining tokens up to the
287 semicolon specify attributes for this identifier. You may use the equal sign
288 to assign values to attributes, and you may use a comma to separate
289 attributes, you may also leave both out. But you <em/must/ use a semicolon to
290 mark the end of the attributes for one identifier. The section above may also
291 have looked like this:
294 # Start of memory section
312 There are of course more attributes for a memory section than just start and
313 size. Start and size are mandatory attributes, that means, each memory area
314 defined <em/must/ have these attributes given (the linker will check that). I
315 will cover other attributes later. As you may have noticed, I've used a
316 comment in the example above. Comments start with a hash mark (`#'), the
317 remainder of the line is ignored if this character is found.
322 Let's assume you have written a program for your trusty old C64, and you would
323 like to run it. For testing purposes, it should run in the <tt/RAM/ area. So
324 we will start to assign segments to memory sections in the <tt/SEGMENTS/
329 CODE: load = RAM1, type = ro;
330 RODATA: load = RAM1, type = ro;
331 DATA: load = RAM1, type = rw;
332 BSS: load = RAM1, type = bss, define = yes;
336 What we are doing here is telling the linker, that all segments go into the
337 <tt/RAM1/ memory area in the order specified in the <tt/SEGMENTS/ section. So
338 the linker will first write the <tt/CODE/ segment, then the <tt/RODATA/
339 segment, then the <tt/DATA/ segment - but it will not write the <tt/BSS/
340 segment. Why? Enter the segment type: For each segment specified, you may also
341 specify a segment attribute. There are five possible segment attributes:
345 wprot same as ro but will be marked as write protected in
346 the VICE label file if -Lp is given
348 bss means that this is an uninitialized segment
349 empty will not go in any output file
350 zp a zeropage segment
353 So, because we specified that the segment with the name BSS is of type bss,
354 the linker knows that this is uninitialized data, and will not write it to an
355 output file. This is an important point: For the assembler, the <tt/BSS/
356 segment has no special meaning. You specify, which segments have the bss
357 attribute when linking. This approach is much more flexible than having one
358 fixed bss segment, and is a result of the design decision to supporting an
359 arbitrary segment count.
361 If you specify "<tt/type = bss/" for a segment, the linker will make sure that
362 this segment does only contain uninitialized data (that is, zeroes), and issue
363 a warning if this is not the case.
365 For a <tt/bss/ type segment to be useful, it must be cleared somehow by your
366 program (this happens usually in the startup code - for example the startup
367 code for cc65 generated programs takes care about that). But how does your
368 code know, where the segment starts, and how big it is? The linker is able to
369 give that information, but you must request it. This is, what we're doing with
370 the "<tt/define = yes/" attribute in the <tt/BSS/ definitions. For each
371 segment, where this attribute is true, the linker will export three symbols.
374 __NAME_LOAD__ This is set to the address where the
376 __NAME_RUN__ This is set to the run address of the
377 segment. We will cover run addresses
379 __NAME_SIZE__ This is set to the segment size.
382 Replace <tt/NAME/ by the name of the segment, in the example above, this would
383 be <tt/BSS/. These symbols may be accessed by your code.
385 Now, as we've configured the linker to write the first three segments and
386 create symbols for the last one, there's only one question left: Where does
387 the linker put the data? It would be very convenient to have the data in a
390 <sect1>Output files<p>
392 We don't have any files specified above, and indeed, this is not needed in a
393 simple configuration like the one above. There is an additional attribute
394 "file" that may be specified for a memory area, that gives a file name to
395 write the area data into. If there is no file name given, the linker will
396 assign the default file name. This is "a.out" or the one given with the
397 <tt><ref id="option-o" name="-o"></tt> option on the command line. Since the
398 default behaviour is ok for our purposes, I did not use the attribute in the
399 example above. Let's have a look at it now.
401 The "file" attribute (the keyword may also be written as "FILE" if you like
402 that better) takes a string enclosed in double quotes (`"') that specifies the
403 file, where the data is written. You may specifiy the same file several times,
404 in that case the data for all memory areas having this file name is written
405 into this file, in the order of the memory areas defined in the <tt/MEMORY/
406 section. Let's specify some file names in the <tt/MEMORY/ section used above:
410 RAM1: start = $0800, size = $9800, file = %O;
411 ROM1: start = $A000, size = $2000, file = "rom1.bin";
412 RAM2: start = $C000, size = $1000, file = %O;
413 ROM2: start = $E000, size = $2000, file = "rom2.bin";
417 The <tt/%O/ used here is a way to specify the default behaviour explicitly:
418 <tt/%O/ is replaced by a string (including the quotes) that contains the
419 default output name, that is, "a.out" or the name specified with the <tt><ref
420 id="option-o" name="-o"></tt> option on the command line. Into this file, the
421 linker will first write any segments that go into <tt/RAM1/, and will append
422 then the segments for <tt/RAM2/, because the memory areas are given in this
423 order. So, for the RAM areas, nothing has really changed.
425 We've not used the ROM areas, but we will do that below, so we give the file
426 names here. Segments that go into <tt/ROM1/ will be written to a file named
427 "rom1.bin", and segments that go into <tt/ROM2/ will be written to a file
428 named "rom2.bin". The name given on the command line is ignored in both cases.
431 <sect1>LOAD and RUN addresses (ROMable code)<p>
433 Let us look now at a more complex example. Say, you've successfully tested
434 your new "Super Operating System" (SOS for short) for the C64, and you
435 will now go and replace the ROMs by your own code. When doing that, you
436 face a new problem: If the code runs in RAM, we need not to care about
437 read/write data. But now, if the code is in ROM, we must care about it.
438 Remember the default segments (you may of course specify your own):
442 RODATA read only data
444 BSS uninitialized data, read/write
447 Since <tt/BSS/ is not initialized, we must not care about it now, but what
448 about <tt/DATA/? <tt/DATA/ contains initialized data, that is, data that was
449 explicitly assigned a value. And your program will rely on these values on
450 startup. Since there's no other way to remember the contents of the data
451 segment, than storing it into one of the ROMs, we have to put it there. But
452 unfortunately, ROM is not writeable, so we have to copy it into RAM before
453 running the actual code.
455 The linker cannot help you copying the data from ROM into RAM (this must be
456 done by the startup code of your program), but it has some features that will
457 help you in this process.
459 First, you may not only specify a "<tt/load/" attribute for a segment, but
460 also a "<tt/run/" attribute. The "<tt/load/" attribute is mandatory, and, if
461 you don't specify a "<tt/run/" attribute, the linker assumes that load area
462 and run area are the same. We will use this feature for our data area:
466 CODE: load = ROM1, type = ro;
467 RODATA: load = ROM2, type = ro;
468 DATA: load = ROM2, run = RAM2, type = rw, define = yes;
469 BSS: load = RAM2, type = bss, define = yes;
473 Let's have a closer look at this <tt/SEGMENTS/ section. We specify that the
474 <tt/CODE/ segment goes into <tt/ROM1/ (the one at $A000). The readonly data
475 goes into <tt/ROM2/. Read/write data will be loaded into <tt/ROM2/ but is run
476 in <tt/RAM2/. That means that all references to labels in the <tt/DATA/
477 segment are relocated to be in <tt/RAM2/, but the segment is written to
478 <tt/ROM2/. All your startup code has to do is, to copy the data from it's
479 location in <tt/ROM2/ to the final location in <tt/RAM2/.
481 So, how do you know, where the data is located? This is the second point,
482 where you get help from the linker. Remember the "<tt/define/" attribute?
483 Since we have set this attribute to true, the linker will define three
484 external symbols for the data segment that may be accessed from your code:
487 __DATA_LOAD__ This is set to the address where the segment
488 is loaded, in this case, it is an address in
490 __DATA_RUN__ This is set to the run address of the segment,
491 in this case, it is an address in RAM2.
492 __DATA_SIZE__ This is set to the segment size.
495 So, what your startup code must do, is to copy <tt/__DATA_SIZE__/ bytes from
496 <tt/__DATA_LOAD__/ to <tt/__DATA_RUN__/ before any other routines are called.
497 All references to labels in the <tt/DATA/ segment are relocated to <tt/RAM2/
498 by the linker, so things will work properly.
501 <sect1>Other MEMORY area attributes<p>
503 There are some other attributes not covered above. Before starting the
504 reference section, I will discuss the remaining things here.
506 You may request symbols definitions also for memory areas. This may be
507 useful for things like a software stack, or an i/o area.
511 STACK: start = $C000, size = $1000, define = yes;
515 This will define three external symbols that may be used in your code:
518 __STACK_START__ This is set to the start of the memory
519 area, $C000 in this example.
520 __STACK_SIZE__ The size of the area, here $1000.
521 __STACK_LAST__ This is NOT the same as START+SIZE.
522 Instead, it it defined as the first
523 address that is not used by data. If we
524 don't define any segments for this area,
525 the value will be the same as START.
528 A memory section may also have a type. Valid types are
531 ro for readonly memory
532 rw for read/write memory.
535 The linker will assure, that no segment marked as read/write or bss is put
536 into a memory area that is marked as readonly.
538 Unused memory in a memory area may be filled. Use the "<tt/fill = yes/"
539 attribute to request this. The default value to fill unused space is zero. If
540 you don't like this, you may specify a byte value that is used to fill these
541 areas with the "<tt/fillval/" attribute. This value is also used to fill unfilled
542 areas generated by the assemblers <tt/.ALIGN/ and <tt/.RES/ directives.
545 <sect1>Other SEGMENT attributes<p>
547 Segments may be aligned to some memory boundary. Specify "<tt/align = num/" to
548 request this feature. Num must be a power of two. To align all segments on a
553 CODE: load = ROM1, type = ro, align = $100;
554 RODATA: load = ROM2, type = ro, align = $100;
555 DATA: load = ROM2, run = RAM2, type = rw, define = yes,
557 BSS: load = RAM2, type = bss, define = yes, align = $100;
561 If an alignment is requested, the linker will add enough space to the output
562 file, so that the new segment starts at an address that is divideable by the
563 given number without a remainder. All addresses are adjusted accordingly. To
564 fill the unused space, bytes of zero are used, or, if the memory area has a
565 "<tt/fillval/" attribute, that value. Alignment is always needed, if you have
566 the used the <tt/.ALIGN/ command in the assembler. The alignment of a segment
567 must be equal or greater than the alignment used in the <tt/.ALIGN/ command.
568 The linker will check that, and issue a warning, if the alignment of a segment
569 is lower than the alignment requested in a <tt/.ALIGN/ command of one of the
570 modules making up this segment.
572 For a given segment you may also specify a fixed offset into a memory area or
573 a fixed start address. Use this if you want the code to run at a specific
574 address (a prominent case is the interrupt vector table which must go at
575 address $FFFA). Only one of <tt/ALIGN/ or <tt/OFFSET/ or <tt/START/ may be
576 specified. If the directive creates empty space, it will be filled with zero,
577 of with the value specified with the "<tt/fillval/" attribute if one is given.
578 The linker will warn you if it is not possible to put the code at the
579 specified offset (this may happen if other segments in this area are too
580 large). Here's an example:
584 VECTORS: load = ROM2, type = ro, start = $FFFA;
588 or (for the segment definitions from above)
592 VECTORS: load = ROM2, type = ro, offset = $1FFA;
596 File names may be empty, data from segments assigned to a memory area with
597 an empty file name is discarded. This is useful, if the a memory area has
598 segments assigned that are empty (for example because they are of type
599 bss). In that case, the linker will create an empty output file. This may
600 be suppressed by assigning an empty file name to that memory area.
602 The symbol <tt/%S/ may be used to access the default start address (that is,
603 $200 or the value given on the command line with the <tt><ref id="option-S"
604 name="-S"></tt> option).
608 <sect1>The FILES section<p>
610 The <tt/FILES/ section is used to support other formats than straight binary
611 (which is the default, so binary output files do not need an explicit entry
612 in the <tt/FILES/ section).
614 The <tt/FILES/ section lists output files and as only attribute the format of
615 each output file. Assigning binary format to the default output file would
624 The only other available output format is the o65 format specified by Andre
625 Fachat. It is defined like this:
633 The necessary o65 attributes are defined in a special section labeled
638 <sect1>The FORMAT section<p>
640 The <tt/FORMAT/ section is used to describe file formats. The default (binary)
641 format has currently no attributes, so, while it may be listed in this
642 section, the attribute list is empty. The second supported format, o65, has
643 several attributes that may be defined here.
647 o65: os = lunix, version = 0, type = small,
648 import = LUNIXKERNEL,
659 In addition to the <tt/MEMORY/ and <tt/SEGMENTS/ sections described above, the
660 linker has features that may be enabled by an additional section labeled
661 <tt/FEATURES/. Currently, one such feature is available: <tt/CONDES/ is used
662 to tell the linker to emit module constructor/destructor tables.
666 CONDES: segment = RODATA,
668 label = __CONSTRUCTOR_TABLE__,
669 count = __CONSTRUCTOR_COUNT__;
673 The <tt/CONDES/ feature has several attributes:
677 <tag><tt>segment</tt></tag>
679 This attribute tells the linker into which segment the table should be
680 placed. If the segment does not exist, it is created.
683 <tag><tt>type</tt></tag>
685 Describes the type of the routines to place in the table. Type may be
686 one of the predefined types <tt/constructor/ or <tt/destructor/, or a
687 numeric value between 0 and 6.
690 <tag><tt>label</tt></tag>
692 This specifies the label to use for the table. The label points to the
693 start of the table in memory and may be used from within user written
697 <tag><tt>count</tt></tag>
699 This is an optional attribute. If specified, an additional symbol is
700 defined by the linker using the given name. The value of this symbol
701 is the number of entries (<em/not/ bytes) in the table. While this
702 attribute is optional, it is often useful to define it.
705 <tag><tt>order</tt></tag>
707 Optional attribute that takes one of the keywords <tt/increasing/ or
708 <tt/decreasing/ as an argument. Specifies the sorting order of the entries
709 within the table. The default is <tt/increasing/, which means that the
710 entries are sorted with increasing priority (the first entry has the lowest
711 priority). You may change this behaviour by specifying <tt/decreasing/ as
712 the argument, the order of entries is reversed in this case.
714 Please note that the order of entries with equal priority is undefined.
718 Without specifying the <tt/CONDES/ feature, the linker will not create any
719 tables, even if there are <tt/condes/ entries in the object files.
721 For more information see the <tt/.CONDES/ command in the <htmlurl
722 url="ca65.html" name="ca65 manual">.
726 <sect1>Builtin configurations<label id="builtin-configs"><p>
728 Here is a list of the builin configurations for the different target
732 <tag><tt>none</tt></tag>
735 RAM: start = %S, size = $10000, file = %O;
738 CODE: load = RAM, type = rw;
739 RODATA: load = RAM, type = rw;
740 DATA: load = RAM, type = rw;
741 BSS: load = RAM, type = bss, define = yes;
744 CONDES: segment = RODATA,
746 label = __CONSTRUCTOR_TABLE__,
747 count = __CONSTRUCTOR_COUNT__;
748 CONDES: segment = RODATA,
750 label = __DESTRUCTOR_TABLE__,
751 count = __DESTRUCTOR_COUNT__;
754 __STACKSIZE__ = $800; # 2K stack
758 <tag><tt>atari</tt></tag>
761 ZP: start = $82, size = $7E, type = rw;
762 HEADER: start = $0000, size = $6, file = %O;
763 RAM: start = $1F00, size = $9D1F, file = %O; # $9D1F: matches upper bound $BC1F
766 EXEHDR: load = HEADER, type = wprot;
767 CODE: load = RAM, type = wprot, define = yes;
768 RODATA: load = RAM, type = wprot;
769 DATA: load = RAM, type = rw;
770 BSS: load = RAM, type = bss, define = yes;
771 ZEROPAGE: load = ZP, type = zp;
772 AUTOSTRT: load = RAM, type = wprot;
775 CONDES: segment = RODATA,
777 label = __CONSTRUCTOR_TABLE__,
778 count = __CONSTRUCTOR_COUNT__;
779 CONDES: segment = RODATA,
781 label = __DESTRUCTOR_TABLE__,
782 count = __DESTRUCTOR_COUNT__;
785 __STACKSIZE__ = $800; # 2K stack
789 <tag><tt>c64</tt></tag>
792 ZP: start = $02, size = $1A, type = rw;
793 RAM: start = $7FF, size = $c801, define = yes, file = %O;
796 CODE: load = RAM, type = wprot;
797 RODATA: load = RAM, type = wprot;
798 DATA: load = RAM, type = rw;
799 BSS: load = RAM, type = bss, define = yes;
800 ZEROPAGE: load = ZP, type = zp;
803 CONDES: segment = RODATA,
805 label = __CONSTRUCTOR_TABLE__,
806 count = __CONSTRUCTOR_COUNT__;
807 CONDES: segment = RODATA,
809 label = __DESTRUCTOR_TABLE__,
810 count = __DESTRUCTOR_COUNT__;
813 __STACKSIZE__ = $800; # 2K stack
817 <tag><tt>c128</tt></tag>
820 ZP: start = $02, size = $1A, type = rw;
821 RAM: start = $1bff, size = $a401, define = yes, file = %O;
824 CODE: load = RAM, type = wprot;
825 RODATA: load = RAM, type = wprot;
826 DATA: load = RAM, type = rw;
827 BSS: load = RAM, type = bss, define = yes;
828 ZEROPAGE: load = ZP, type = zp;
831 CONDES: segment = RODATA,
833 label = __CONSTRUCTOR_TABLE__,
834 count = __CONSTRUCTOR_COUNT__;
835 CONDES: segment = RODATA,
837 label = __DESTRUCTOR_TABLE__,
838 count = __DESTRUCTOR_COUNT__;
839 CONDES: segment = RODATA,
841 label = __IRQFUNC_TABLE__,
842 count = __IRQFUNC_COUNT__;
845 __STACKSIZE__ = $800; # 2K stack
849 <tag><tt>plus4</tt></tag>
852 ZP: start = $02, size = $1A, type = rw;
853 RAM: start = $0fff, size = $7001, file = %O;
856 CODE: load = RAM, type = wprot;
857 RODATA: load = RAM, type = wprot;
858 DATA: load = RAM, type = rw;
859 BSS: load = RAM, type = bss, define = yes;
860 ZEROPAGE: load = ZP, type = zp;
863 CONDES: segment = RODATA,
865 label = __CONSTRUCTOR_TABLE__,
866 count = __CONSTRUCTOR_COUNT__;
867 CONDES: segment = RODATA,
869 label = __DESTRUCTOR_TABLE__,
870 count = __DESTRUCTOR_COUNT__;
873 __STACKSIZE__ = $800; # 2K stack
877 <tag><tt>cbm510</tt></tag>
880 ZP: start = $02, size = $1A, type = rw;
881 RAM: start = $0001, size = $F3FF, file = %O;
882 VIDRAM: start = $F400, size = $0400, define = yes, file = "";
885 CODE: load = RAM, type = wprot;
886 RODATA: load = RAM, type = wprot;
887 DATA: load = RAM, type = rw;
888 BSS: load = RAM, type = bss, define = yes;
889 ZEROPAGE: load = ZP, type = zp;
892 CONDES: segment = RODATA,
894 label = __CONSTRUCTOR_TABLE__,
895 count = __CONSTRUCTOR_COUNT__;
896 CONDES: segment = RODATA,
898 label = __DESTRUCTOR_TABLE__,
899 count = __DESTRUCTOR_COUNT__;
900 CONDES: segment = RODATA,
902 label = __IRQFUNC_TABLE__,
903 count = __IRQFUNC_COUNT__;
906 __STACKSIZE__ = $781; # ~2K stack
910 <tag><tt>cbm610</tt></tag>
913 ZP: start = $02, size = $1A, type = rw;
914 RAM: start = $0001, size = $FFF0, file = %O;
917 CODE: load = RAM, type = wprot;
918 RODATA: load = RAM, type = wprot;
919 DATA: load = RAM, type = rw;
920 BSS: load = RAM, type = bss, define = yes;
921 ZEROPAGE: load = ZP, type = zp;
924 CONDES: segment = RODATA,
926 label = __CONSTRUCTOR_TABLE__,
927 count = __CONSTRUCTOR_COUNT__;
928 CONDES: segment = RODATA,
930 label = __DESTRUCTOR_TABLE__,
931 count = __DESTRUCTOR_COUNT__;
934 __STACKSIZE__ = $800; # 2K stack
938 <tag><tt>pet</tt></tag>
941 ZP: start = $02, size = $1A, type = rw;
942 RAM: start = $03FF, size = $7BFF, file = %O;
945 CODE: load = RAM, type = wprot;
946 RODATA: load = RAM, type = wprot;
947 DATA: load = RAM, type = rw;
948 BSS: load = RAM, type = bss, define = yes;
949 ZEROPAGE: load = ZP, type = zp;
952 CONDES: segment = RODATA,
954 label = __CONSTRUCTOR_TABLE__,
955 count = __CONSTRUCTOR_COUNT__;
956 CONDES: segment = RODATA,
958 label = __DESTRUCTOR_TABLE__,
959 count = __DESTRUCTOR_COUNT__;
962 __STACKSIZE__ = $800; # 2K stack
966 <tag><tt>apple2</tt></tag>
969 ZP: start = $00, size = $1A, type = rw;
970 RAM: start = $800, size = $8E00, file = %O;
973 CODE: load = RAM, type = ro;
974 RODATA: load = RAM, type = ro;
975 DATA: load = RAM, type = rw;
976 BSS: load = RAM, type = bss, define = yes;
977 ZEROPAGE: load = ZP, type = zp;
980 CONDES: segment = RODATA,
982 label = __CONSTRUCTOR_TABLE__,
983 count = __CONSTRUCTOR_COUNT__;
984 CONDES: segment = RODATA,
986 label = __DESTRUCTOR_TABLE__,
987 count = __DESTRUCTOR_COUNT__;
990 __STACKSIZE__ = $800; # 2K stack
994 <tag><tt>geos</tt></tag>
997 HEADER: start = $204, size = 508, file = %O;
998 RAM: start = $400, size = $5C00, file = %O;
1001 HEADER: load = HEADER, type = ro;
1002 CODE: load = RAM, type = ro;
1003 RODATA: load = RAM, type = ro;
1004 DATA: load = RAM, type = rw;
1005 BSS: load = RAM, type = bss, define = yes;
1008 CONDES: segment = RODATA,
1010 label = __CONSTRUCTOR_TABLE__,
1011 count = __CONSTRUCTOR_COUNT__;
1012 CONDES: segment = RODATA,
1014 label = __DESTRUCTOR_TABLE__,
1015 count = __DESTRUCTOR_COUNT__;
1018 __STACKSIZE__ = $800; # 2K stack
1024 The "<tt/start/" attribute for the <tt/RAM/ memory area of the CBM systems is
1025 two less than the actual start of the basic RAM to account for the two bytes
1026 load address that is needed on disk and supplied by the startup code.
1030 <sect>Bugs/Feedback<p>
1032 If you have problems using the linker, if you find any bugs, or if you're
1033 doing something interesting with it, I would be glad to hear from you. Feel
1034 free to contact me by email (<htmlurl url="mailto:uz@cc65.org"
1035 name="uz@cc65.org">).
1041 ld65 (and all cc65 binutils) are (C) Copyright 1998-2001 Ullrich von
1042 Bassewitz. For usage of the binaries and/or sources the following
1043 conditions do apply:
1045 This software is provided 'as-is', without any expressed or implied
1046 warranty. In no event will the authors be held liable for any damages
1047 arising from the use of this software.
1049 Permission is granted to anyone to use this software for any purpose,
1050 including commercial applications, and to alter it and redistribute it
1051 freely, subject to the following restrictions:
1054 <item> The origin of this software must not be misrepresented; you must not
1055 claim that you wrote the original software. If you use this software
1056 in a product, an acknowledgment in the product documentation would be
1057 appreciated but is not required.
1058 <item> Altered source versions must be plainly marked as such, and must not
1059 be misrepresented as being the original software.
1060 <item> This notice may not be removed or altered from any source