1 <!doctype linuxdoc system>
4 <title>ld65 Users Guide
5 <author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
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 ...
59 -m name Create a map file
60 -o name Name the default output file
61 -t sys Set the target system
64 -C name Use linker config file
65 -Ln name Create a VICE label file
66 -Lp Mark write protected segments as such (VICE)
67 -S addr Set the default start address
68 -V Print the linker version
71 --help Help (this text)
72 --mapfile name Create a map file
73 --target sys Set the target system
74 --version Print the linker version
75 ---------------------------------------------------------------------------
79 <sect1>Command line options in detail<p>
81 Here is a description of all the command line options:
85 <tag><tt>-h, --help</tt></tag>
87 Print the short option summary shown above.
91 <tag><tt>-m name, --mapfile name</tt></tag>
93 This option (which needs an argument that will used as a filename for
94 the generated map file) will cause the linker to generate a map file.
95 The map file does contain a detailed overview over the modules used, the
96 sizes for the different segments, and a table containing exported
100 <label id="option-o">
101 <tag><tt>-o name</tt></tag>
103 The -o switch is used to give the name of the default output file.
104 Depending on your output configuration, this name may NOT be used as
105 name for the output file. However, for the builtin configurations, this
106 name is used for the output file name.
109 <label id="option-t">
110 <tag><tt>-t sys, --target sys</tt></tag>
112 The argument for the -t switch is the name of the target system. Since this
113 switch will activate a builtin configuration, it may not be used together
114 with the <tt><ref id="option-C" name="-C"></tt> option. The following target
115 systems are currently supported:
123 <item>cbm510 (CBM-II series with 40 column video)
124 <item>cbm610 (all CBM series-II computers with 80 column video)
125 <item>pet (all CBM PET systems except the 2001)
130 There are a few more targets defined but neither of them is actually
131 supported. See <ref id="builtin-configs" name="builtin configurations"> for
135 <label id="option-v">
136 <tag><tt>-v, --verbose</tt></tag>
138 Using the -v option, you may enable more output that may help you to
139 locate problems. If an undefined symbol is encountered, -v causes the
140 linker to print a detailed list of the references (that is, source file
141 and line) for this symbol.
144 <tag><tt>-vm</tt></tag>
146 Must be used in conjunction with <tt><ref id="option-m" name="-m"></tt>
147 (generate map file). Normally the map file will not include empty segments
148 and sections, or unreferenced symbols. Using this option, you can force the
149 linker to include all this information into the map file.
152 <label id="option-C">
153 <tag><tt>-C</tt></tag>
155 This gives the name of an output config file to use. See section 4 for more
156 information about config files. -C may not be used together with <tt><ref
157 id="option-t" name="-t"></tt>.
160 <tag><tt>-Ln</tt></tag>
162 This option allows you to create a file that contains all global labels and
163 may be loaded into VICE emulator using the <tt/ll/ (load label) command. You
164 may use this to debug your code with VICE. Note: Older versions had some
165 bugs in the label code. If you have problems, please get the latest VICE
169 <tag><tt>-Lp</tt></tag>
174 <label id="option-S">
175 <tag><tt>-S addr, --start-addr addr</tt></tag>
177 Using -S you may define the default starting address. If and how this
178 address is used depends on the config file in use. For the builtin
179 configurations, only the "none" system honors an explicit start address,
180 all other builtin config provide their own.
183 <tag><tt>-V, --version</tt></tag>
185 This option print the version number of the linker. If you send any
186 suggestions or bugfixes, please include this number.
190 If one of the modules is not found in the current directory, and the module
191 name does not have a path component, the value of the environment variable
192 <tt/CC65_LIB/ is prepended to the name, and the linker tries to open the
193 module with this new name.
197 <sect>Detailed workings<p>
199 The linker does several things when combining object modules:
201 First, the command line is parsed from left to right. For each object file
202 encountered (object files are recognized by a magic word in the header, so
203 the linker does not care about the name), imported and exported
204 identifiers are read from the file and inserted in a table. If a library
205 name is given (libraries are also recognized by a magic word, there are no
206 special naming conventions), all modules in the library are checked if an
207 export from this module would satisfy an import from other modules. All
208 modules where this is the case are marked. If duplicate identifiers are
209 found, the linker issues a warning.
211 This procedure (parsing and reading from left to right) does mean, that a
212 library may only satisfy references for object modules (given directly or from
213 a library) named <em/before/ that library. With the command line
216 ld65 crt0.o clib.lib test.o
219 the module test.o may not contain references to modules in the library
220 clib.lib. If this is the case, you have to change the order of the modules
224 ld65 crt0.o test.o clib.lib
227 Step two is, to read the configuration file, and assign start addresses
228 for the segments and define any linker symbols (see <ref id="config-files"
229 name="Configuration files">).
231 After that, the linker is ready to produce an output file. Before doing that,
232 it checks it's data for consistency. That is, it checks for unresolved
233 externals (if the output format is not relocatable) and for symbol type
234 mismatches (for example a zero page symbol is imported by a module as absolute
237 Step four is, to write the actual target files. In this step, the linker will
238 resolve any expressions contained in the segment data. Circular references are
239 also detected in this step (a symbol may have a circular reference that goes
240 unnoticed if the symbol is not used).
242 Step five is to output a map file with a detailed list of all modules,
243 segments and symbols encountered.
245 And, last step, if you give the <tt><ref id="option-v" name="-v"></tt> switch
246 twice, you get a dump of the segment data. However, this may be quite
247 unreadable if you're not a developer:-)
251 <sect>Configuration files<label id="config-files"><p>
253 Configuration files are used to describe the layout of the output file(s). Two
254 major topics are covered in a config file: The memory layout of the target
255 architecture, and the assignment of segments to memory areas. In addition,
256 several other attributes may be specified.
258 Case is ignored for keywords, that is, section or attribute names, but it is
259 <em/not/ ignored for names and strings.
263 <sect1>Memory areas<p>
265 Memory areas are specified in a <tt/MEMORY/ section. Lets have a look at an
266 example (this one describes the usable memory layout of the C64):
270 RAM1: start = $0800, size = $9800;
271 ROM1: start = $A000, size = $2000;
272 RAM2: start = $C000, size = $1000;
273 ROM2: start = $E000, size = $2000;
277 As you can see, there are two ram areas and two rom areas. The names
278 (before the colon) are arbitrary names that must start with a letter, with
279 the remaining characters being letters or digits. The names of the memory
280 areas are used when assigning segments. As mentioned above, case is
281 significant for these names.
283 The syntax above is used in all sections of the config file. The name
284 (<tt/ROM1/ etc.) is said to be an identifier, the remaining tokens up to the
285 semicolon specify attributes for this identifier. You may use the equal sign
286 to assign values to attributes, and you may use a comma to separate
287 attributes, you may also leave both out. But you <em/must/ use a semicolon to
288 mark the end of the attributes for one identifier. The section above may also
289 have looked like this:
292 # Start of memory section
310 There are of course more attributes for a memory section than just start and
311 size. Start and size are mandatory attributes, that means, each memory area
312 defined <em/must/ have these attributes given (the linker will check that). I
313 will cover other attributes later. As you may have noticed, I've used a
314 comment in the example above. Comments start with a hash mark (`#'), the
315 remainder of the line is ignored if this character is found.
320 Let's assume you have written a program for your trusty old C64, and you would
321 like to run it. For testing purposes, it should run in the <tt/RAM/ area. So
322 we will start to assign segments to memory sections in the <tt/SEGMENTS/
327 CODE: load = RAM1, type = ro;
328 RODATA: load = RAM1, type = ro;
329 DATA: load = RAM1, type = rw;
330 BSS: load = RAM1, type = bss, define = yes;
334 What we are doing here is telling the linker, that all segments go into the
335 <tt/RAM1/ memory area in the order specified in the <tt/SEGMENTS/ section. So
336 the linker will first write the <tt/CODE/ segment, then the <tt/RODATA/
337 segment, then the <tt/DATA/ segment - but it will not write the <tt/BSS/
338 segment. Why? Enter the segment type: For each segment specified, you may also
339 specify a segment attribute. There are five possible segment attributes:
343 wprot same as ro but will be marked as write protected in
344 the VICE label file if -Lp is given
346 bss means that this is an uninitialized segment
347 empty will not go in any output file
348 zp a zeropage segment
351 So, because we specified that the segment with the name BSS is of type bss,
352 the linker knows that this is uninitialized data, and will not write it to an
353 output file. This is an important point: For the assembler, the <tt/BSS/
354 segment has no special meaning. You specify, which segments have the bss
355 attribute when linking. This approach is much more flexible than having one
356 fixed bss segment, and is a result of the design decision to supporting an
357 arbitrary segment count.
359 If you specify "<tt/type = bss/" for a segment, the linker will make sure that
360 this segment does only contain uninitialized data (that is, zeroes), and issue
361 a warning if this is not the case.
363 For a <tt/bss/ type segment to be useful, it must be cleared somehow by your
364 program (this happens usually in the startup code - for example the startup
365 code for cc65 generated programs takes care about that). But how does your
366 code know, where the segment starts, and how big it is? The linker is able to
367 give that information, but you must request it. This is, what we're doing with
368 the "<tt/define = yes/" attribute in the <tt/BSS/ definitions. For each
369 segment, where this attribute is true, the linker will export three symbols.
372 __NAME_LOAD__ This is set to the address where the
374 __NAME_RUN__ This is set to the run address of the
375 segment. We will cover run addresses
377 __NAME_SIZE__ This is set to the segment size.
380 Replace <tt/NAME/ by the name of the segment, in the example above, this would
381 be <tt/BSS/. These symbols may be accessed by your code.
383 Now, as we've configured the linker to write the first three segments and
384 create symbols for the last one, there's only one question left: Where does
385 the linker put the data? It would be very convenient to have the data in a
388 <sect1>Output files<p>
390 We don't have any files specified above, and indeed, this is not needed in a
391 simple configuration like the one above. There is an additional attribute
392 "file" that may be specified for a memory area, that gives a file name to
393 write the area data into. If there is no file name given, the linker will
394 assign the default file name. This is "a.out" or the one given with the
395 <tt><ref id="option-o" name="-o"></tt> option on the command line. Since the
396 default behaviour is ok for our purposes, I did not use the attribute in the
397 example above. Let's have a look at it now.
399 The "file" attribute (the keyword may also be written as "FILE" if you like
400 that better) takes a string enclosed in double quotes (`"') that specifies the
401 file, where the data is written. You may specifiy the same file several times,
402 in that case the data for all memory areas having this file name is written
403 into this file, in the order of the memory areas defined in the <tt/MEMORY/
404 section. Let's specify some file names in the <tt/MEMORY/ section used above:
408 RAM1: start = $0800, size = $9800, file = %O;
409 ROM1: start = $A000, size = $2000, file = "rom1.bin";
410 RAM2: start = $C000, size = $1000, file = %O;
411 ROM2: start = $E000, size = $2000, file = "rom2.bin";
415 The <tt/%O/ used here is a way to specify the default behaviour explicitly:
416 <tt/%O/ is replaced by a string (including the quotes) that contains the
417 default output name, that is, "a.out" or the name specified with the <tt><ref
418 id="option-o" name="-o"></tt> option on the command line. Into this file, the
419 linker will first write any segments that go into <tt/RAM1/, and will append
420 then the segments for <tt/RAM2/, because the memory areas are given in this
421 order. So, for the RAM areas, nothing has really changed.
423 We've not used the ROM areas, but we will do that below, so we give the file
424 names here. Segments that go into <tt/ROM1/ will be written to a file named
425 "rom1.bin", and segments that go into <tt/ROM2/ will be written to a file
426 named "rom2.bin". The name given on the command line is ignored in both cases.
429 <sect1>LOAD and RUN addresses (ROMable code)<p>
431 Let us look now at a more complex example. Say, you've successfully tested
432 your new "Super Operating System" (SOS for short) for the C64, and you
433 will now go and replace the ROMs by your own code. When doing that, you
434 face a new problem: If the code runs in RAM, we need not to care about
435 read/write data. But now, if the code is in ROM, we must care about it.
436 Remember the default segments (you may of course specify your own):
440 RODATA read only data
442 BSS uninitialized data, read/write
445 Since <tt/BSS/ is not initialized, we must not care about it now, but what
446 about <tt/DATA/? <tt/DATA/ contains initialized data, that is, data that was
447 explicitly assigned a value. And your program will rely on these values on
448 startup. Since there's no other way to remember the contents of the data
449 segment, than storing it into one of the ROMs, we have to put it there. But
450 unfortunately, ROM is not writeable, so we have to copy it into RAM before
451 running the actual code.
453 The linker cannot help you copying the data from ROM into RAM (this must be
454 done by the startup code of your program), but it has some features that will
455 help you in this process.
457 First, you may not only specify a "<tt/load/" attribute for a segment, but
458 also a "<tt/run/" attribute. The "<tt/load/" attribute is mandatory, and, if
459 you don't specify a "<tt/run/" attribute, the linker assumes that load area
460 and run area are the same. We will use this feature for our data area:
464 CODE: load = ROM1, type = ro;
465 RODATA: load = ROM2, type = ro;
466 DATA: load = ROM2, run = RAM2, type = rw, define = yes;
467 BSS: load = RAM2, type = bss, define = yes;
471 Let's have a closer look at this <tt/SEGMENTS/ section. We specify that the
472 <tt/CODE/ segment goes into <tt/ROM1/ (the one at $A000). The readonly data
473 goes into <tt/ROM2/. Read/write data will be loaded into <tt/ROM2/ but is run
474 in <tt/RAM2/. That means that all references to labels in the <tt/DATA/
475 segment are relocated to be in <tt/RAM2/, but the segment is written to
476 <tt/ROM2/. All your startup code has to do is, to copy the data from it's
477 location in <tt/ROM2/ to the final location in <tt/RAM2/.
479 So, how do you know, where the data is located? This is the second point,
480 where you get help from the linker. Remember the "<tt/define/" attribute?
481 Since we have set this attribute to true, the linker will define three
482 external symbols for the data segment that may be accessed from your code:
485 __DATA_LOAD__ This is set to the address where the segment
486 is loaded, in this case, it is an address in
488 __DATA_RUN__ This is set to the run address of the segment,
489 in this case, it is an address in RAM2.
490 __DATA_SIZE__ This is set to the segment size.
493 So, what your startup code must do, is to copy <tt/__DATA_SIZE__/ bytes from
494 <tt/__DATA_LOAD__/ to <tt/__DATA_RUN__/ before any other routines are called.
495 All references to labels in the <tt/DATA/ segment are relocated to <tt/RAM2/
496 by the linker, so things will work properly.
499 <sect1>Other MEMORY area attributes<p>
501 There are some other attributes not covered above. Before starting the
502 reference section, I will discuss the remaining things here.
504 You may request symbols definitions also for memory areas. This may be
505 useful for things like a software stack, or an i/o area.
509 STACK: start = $C000, size = $1000, define = yes;
513 This will define three external symbols that may be used in your code:
516 __STACK_START__ This is set to the start of the memory
517 area, $C000 in this example.
518 __STACK_SIZE__ The size of the area, here $1000.
519 __STACK_LAST__ This is NOT the same as START+SIZE.
520 Instead, it it defined as the first
521 address that is not used by data. If we
522 don't define any segments for this area,
523 the value will be the same as START.
526 A memory section may also have a type. Valid types are
529 ro for readonly memory
530 rw for read/write memory.
533 The linker will assure, that no segment marked as read/write or bss is put
534 into a memory area that is marked as readonly.
536 Unused memory in a memory area may be filled. Use the "<tt/fill = yes/"
537 attribute to request this. The default value to fill unused space is zero. If
538 you don't like this, you may specify a byte value that is used to fill these
539 areas with the "<tt/fillval/" attribute. This value is also used to fill unfilled
540 areas generated by the assemblers <tt/.ALIGN/ and <tt/.RES/ directives.
543 <sect1>Other SEGMENT attributes<p>
545 Segments may be aligned to some memory boundary. Specify "<tt/align = num/" to
546 request this feature. Num must be a power of two. To align all segments on a
551 CODE: load = ROM1, type = ro, align = $100;
552 RODATA: load = ROM2, type = ro, align = $100;
553 DATA: load = ROM2, run = RAM2, type = rw, define = yes,
555 BSS: load = RAM2, type = bss, define = yes, align = $100;
559 If an alignment is requested, the linker will add enough space to the output
560 file, so that the new segment starts at an address that is divideable by the
561 given number without a remainder. All addresses are adjusted accordingly. To
562 fill the unused space, bytes of zero are used, or, if the memory area has a
563 "<tt/fillval/" attribute, that value. Alignment is always needed, if you have
564 the used the <tt/.ALIGN/ command in the assembler. The alignment of a segment
565 must be equal or greater than the alignment used in the <tt/.ALIGN/ command.
566 The linker will check that, and issue a warning, if the alignment of a segment
567 is lower than the alignment requested in a <tt/.ALIGN/ command of one of the
568 modules making up this segment.
570 For a given segment you may also specify a fixed offset into a memory area or
571 a fixed start address. Use this if you want the code to run at a specific
572 address (a prominent case is the interrupt vector table which must go at
573 address $FFFA). Only one of <tt/ALIGN/ or <tt/OFFSET/ or <tt/START/ may be
574 specified. If the directive creates empty space, it will be filled with zero,
575 of with the value specified with the "<tt/fillval/" attribute if one is given.
576 The linker will warn you if it is not possible to put the code at the
577 specified offset (this may happen if other segments in this area are too
578 large). Here's an example:
582 VECTORS: load = ROM2, type = ro, start = $FFFA;
586 or (for the segment definitions from above)
590 VECTORS: load = ROM2, type = ro, offset = $1FFA;
594 File names may be empty, data from segments assigned to a memory area with
595 an empty file name is discarded. This is useful, if the a memory area has
596 segments assigned that are empty (for example because they are of type
597 bss). In that case, the linker will create an empty output file. This may
598 be suppressed by assigning an empty file name to that memory area.
600 The symbol <tt/%S/ may be used to access the default start address (that is,
601 $200 or the value given on the command line with the <tt><ref id="option-S"
602 name="-S"></tt> option).
608 In addition to the <tt/MEMORY/ and <tt/SEGMENTS/ sections described above, the
609 linker has features that may be enabled by an additional section labeled
610 <tt/FEATURES/. Currently, one such feature is available: <tt/CONDES/ is used
611 to tell the linker to emit module constructor/destructor tables.
615 CONDES: segment = RODATA,
617 label = __CONSTRUCTOR_TABLE__,
618 count = __CONSTRUCTOR_COUNT__;
622 The <tt/CONDES/ feature has several attributes:
626 <tag><tt>segment</tt></tag>
628 This attribute tells the linker into which segment the table should be
629 placed. If the segment does not exist, it is created.
632 <tag><tt>type</tt></tag>
634 Describes the type of the routines to place in the table. Type may be
635 one of the predefined types <tt/constructor/ or <tt/destructor/, or a
636 numeric value between 0 and 6.
639 <tag><tt>label</tt></tag>
641 This specifies the label to use for the table. The label points to the
642 start of the table in memory and may be used from within user written
646 <tag><tt>count</tt></tag>
648 This is an optional attribute. If specified, an additional symbol is
649 defined by the linker using the given name. The value of this symbol
650 is the number of entries (<em/not/ bytes) in the table. While this
651 attribute is optional, it is often useful to define it.
654 <tag><tt>order</tt></tag>
656 Optional attribute that takes one of the keywords <tt/increasing/ or
657 <tt/decreasing/ as an argument. Specifies the sorting order of the entries
658 within the table. The default is <tt/increasing/, which means that the
659 entries are sorted with increasing priority (the first entry has the lowest
660 priority). You may change this behaviour by specifying <tt/decreasing/ as
661 the argument, the order of entries is reversed in this case.
663 Please note that the order of entries with equal priority is undefined.
667 Without specifying the <tt/CONDES/ feature, the linker will not create any
668 tables, even if there are <tt/condes/ entries in the object files.
670 For more information see the <tt/.CONDES/ command in the <htmlurl
671 url="ca65.html" name="ca65 manual">.
675 <sect1>Builtin configurations<label id="builtin-configs"><p>
677 Here is a list of the builin configurations for the different target
681 <tag><tt>none</tt></tag>
684 RAM: start = %S, size = $10000, file = %O;
687 CODE: load = RAM, type = rw;
688 RODATA: load = RAM, type = rw;
689 DATA: load = RAM, type = rw;
690 BSS: load = RAM, type = bss, define = yes;
693 CONDES: segment = RODATA,
695 label = __CONSTRUCTOR_TABLE__,
696 count = __CONSTRUCTOR_COUNT__;
697 CONDES: segment = RODATA,
699 label = __DESTRUCTOR_TABLE__,
700 count = __DESTRUCTOR_COUNT__;
703 __STACKSIZE__ = $800; # 2K stack
707 <tag><tt>atari</tt></tag>
710 ZP: start = $82, size = $7E, type = rw;
711 HEADER: start = $0000, size = $6, file = %O;
712 RAM: start = $1F00, size = $9D1F, file = %O; # $9D1F: matches upper bound $BC1F
715 EXEHDR: load = HEADER, type = wprot;
716 CODE: load = RAM, type = wprot, define = yes;
717 RODATA: load = RAM, type = wprot;
718 DATA: load = RAM, type = rw;
719 BSS: load = RAM, type = bss, define = yes;
720 ZEROPAGE: load = ZP, type = zp;
721 AUTOSTRT: load = RAM, type = wprot;
724 CONDES: segment = RODATA,
726 label = __CONSTRUCTOR_TABLE__,
727 count = __CONSTRUCTOR_COUNT__;
728 CONDES: segment = RODATA,
730 label = __DESTRUCTOR_TABLE__,
731 count = __DESTRUCTOR_COUNT__;
734 __STACKSIZE__ = $800; # 2K stack
738 <tag><tt>c64</tt></tag>
741 ZP: start = $02, size = $1A, type = rw;
742 RAM: start = $7FF, size = $c801, define = yes, file = %O;
745 CODE: load = RAM, type = wprot;
746 RODATA: load = RAM, type = wprot;
747 DATA: load = RAM, type = rw;
748 BSS: load = RAM, type = bss, define = yes;
749 ZEROPAGE: load = ZP, type = zp;
752 CONDES: segment = RODATA,
754 label = __CONSTRUCTOR_TABLE__,
755 count = __CONSTRUCTOR_COUNT__;
756 CONDES: segment = RODATA,
758 label = __DESTRUCTOR_TABLE__,
759 count = __DESTRUCTOR_COUNT__;
762 __STACKSIZE__ = $800; # 2K stack
766 <tag><tt>c128</tt></tag>
769 ZP: start = $02, size = $1A, type = rw;
770 RAM: start = $1bff, size = $a401, define = yes, file = %O;
773 CODE: load = RAM, type = wprot;
774 RODATA: load = RAM, type = wprot;
775 DATA: load = RAM, type = rw;
776 BSS: load = RAM, type = bss, define = yes;
777 ZEROPAGE: load = ZP, type = zp;
780 CONDES: segment = RODATA,
782 label = __CONSTRUCTOR_TABLE__,
783 count = __CONSTRUCTOR_COUNT__;
784 CONDES: segment = RODATA,
786 label = __DESTRUCTOR_TABLE__,
787 count = __DESTRUCTOR_COUNT__;
788 CONDES: segment = RODATA,
790 label = __IRQFUNC_TABLE__,
791 count = __IRQFUNC_COUNT__;
794 __STACKSIZE__ = $800; # 2K stack
798 <tag><tt>plus4</tt></tag>
801 ZP: start = $02, size = $1A, type = rw;
802 RAM: start = $0fff, size = $7001, file = %O;
805 CODE: load = RAM, type = wprot;
806 RODATA: load = RAM, type = wprot;
807 DATA: load = RAM, type = rw;
808 BSS: load = RAM, type = bss, define = yes;
809 ZEROPAGE: load = ZP, type = zp;
812 CONDES: segment = RODATA,
814 label = __CONSTRUCTOR_TABLE__,
815 count = __CONSTRUCTOR_COUNT__;
816 CONDES: segment = RODATA,
818 label = __DESTRUCTOR_TABLE__,
819 count = __DESTRUCTOR_COUNT__;
822 __STACKSIZE__ = $800; # 2K stack
826 <tag><tt>cbm510</tt></tag>
829 ZP: start = $02, size = $1A, type = rw;
830 RAM: start = $0001, size = $F3FF, file = %O;
831 VIDRAM: start = $F400, size = $0400, define = yes, file = "";
834 CODE: load = RAM, type = wprot;
835 RODATA: load = RAM, type = wprot;
836 DATA: load = RAM, type = rw;
837 BSS: load = RAM, type = bss, define = yes;
838 ZEROPAGE: load = ZP, type = zp;
841 CONDES: segment = RODATA,
843 label = __CONSTRUCTOR_TABLE__,
844 count = __CONSTRUCTOR_COUNT__;
845 CONDES: segment = RODATA,
847 label = __DESTRUCTOR_TABLE__,
848 count = __DESTRUCTOR_COUNT__;
851 __STACKSIZE__ = $781; # ~2K stack
855 <tag><tt>cbm610</tt></tag>
858 ZP: start = $02, size = $1A, type = rw;
859 RAM: start = $0001, size = $FFF0, file = %O;
862 CODE: load = RAM, type = wprot;
863 RODATA: load = RAM, type = wprot;
864 DATA: load = RAM, type = rw;
865 BSS: load = RAM, type = bss, define = yes;
866 ZEROPAGE: load = ZP, type = zp;
869 CONDES: segment = RODATA,
871 label = __CONSTRUCTOR_TABLE__,
872 count = __CONSTRUCTOR_COUNT__;
873 CONDES: segment = RODATA,
875 label = __DESTRUCTOR_TABLE__,
876 count = __DESTRUCTOR_COUNT__;
879 __STACKSIZE__ = $800; # 2K stack
883 <tag><tt>pet</tt></tag>
886 ZP: start = $02, size = $1A, type = rw;
887 RAM: start = $03FF, size = $7BFF, file = %O;
890 CODE: load = RAM, type = wprot;
891 RODATA: load = RAM, type = wprot;
892 DATA: load = RAM, type = rw;
893 BSS: load = RAM, type = bss, define = yes;
894 ZEROPAGE: load = ZP, type = zp;
897 CONDES: segment = RODATA,
899 label = __CONSTRUCTOR_TABLE__,
900 count = __CONSTRUCTOR_COUNT__;
901 CONDES: segment = RODATA,
903 label = __DESTRUCTOR_TABLE__,
904 count = __DESTRUCTOR_COUNT__;
907 __STACKSIZE__ = $800; # 2K stack
911 <tag><tt>apple2</tt></tag>
914 ZP: start = $00, size = $1A, type = rw;
915 RAM: start = $800, size = $8E00, file = %O;
918 CODE: load = RAM, type = ro;
919 RODATA: load = RAM, type = ro;
920 DATA: load = RAM, type = rw;
921 BSS: load = RAM, type = bss, define = yes;
922 ZEROPAGE: load = ZP, type = zp;
925 CONDES: segment = RODATA,
927 label = __CONSTRUCTOR_TABLE__,
928 count = __CONSTRUCTOR_COUNT__;
929 CONDES: segment = RODATA,
931 label = __DESTRUCTOR_TABLE__,
932 count = __DESTRUCTOR_COUNT__;
935 __STACKSIZE__ = $800; # 2K stack
939 <tag><tt>geos</tt></tag>
942 HEADER: start = $204, size = 508, file = %O;
943 RAM: start = $400, size = $5C00, file = %O;
946 HEADER: load = HEADER, type = ro;
947 CODE: load = RAM, type = ro;
948 RODATA: load = RAM, type = ro;
949 DATA: load = RAM, type = rw;
950 BSS: load = RAM, type = bss, define = yes;
953 CONDES: segment = RODATA,
955 label = __CONSTRUCTOR_TABLE__,
956 count = __CONSTRUCTOR_COUNT__;
957 CONDES: segment = RODATA,
959 label = __DESTRUCTOR_TABLE__,
960 count = __DESTRUCTOR_COUNT__;
963 __STACKSIZE__ = $800; # 2K stack
969 The "<tt/start/" attribute for the <tt/RAM/ memory area of the CBM systems is
970 two less than the actual start of the basic RAM to account for the two bytes
971 load address that is needed on disk and supplied by the startup code.
975 <sect>Bugs/Feedback<p>
977 If you have problems using the linker, if you find any bugs, or if you're
978 doing something interesting with it, I would be glad to hear from you. Feel
979 free to contact me by email (<htmlurl url="mailto:uz@cc65.org"
980 name="uz@cc65.org">).
986 ld65 (and all cc65 binutils) are (C) Copyright 1998-2001 Ullrich von
987 Bassewitz. For usage of the binaries and/or sources the following
990 This software is provided 'as-is', without any expressed or implied
991 warranty. In no event will the authors be held liable for any damages
992 arising from the use of this software.
994 Permission is granted to anyone to use this software for any purpose,
995 including commercial applications, and to alter it and redistribute it
996 freely, subject to the following restrictions:
999 <item> The origin of this software must not be misrepresented; you must not
1000 claim that you wrote the original software. If you use this software
1001 in a product, an acknowledgment in the product documentation would be
1002 appreciated but is not required.
1003 <item> Altered source versions must be plainly marked as such, and must not
1004 be misrepresented as being the original software.
1005 <item> This notice may not be removed or altered from any source