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This is or1k.info, produced by makeinfo version 4.13 from../.././gdb/doc/or1k.texinfo.INFO-DIR-SECTION Software developmentSTART-INFO-DIR-ENTRY* Gdb for OpenRISC 1000: (gdb for Or1K). The GNU debugger for OpenRISC 1000.END-INFO-DIR-ENTRYThis file documents the GNU debugger GDB when used with OpenRISC1000 processors.This is the Second Edition, of `Debugging the OpenRISC 1000 GDB' forGDB Version 6.8.Copyright (C) 2008 Embecosm LimitedPermission is granted to copy, distribute and/or modify this documentunder the terms of the GNU Free Documentation License, Version 3 or anylater version published by the Free Software Foundation; with theFront-Cover Texts being "Debugging the OpenRISC 1000 with GDB by JeremyBennett" and with the Back-Cover Texts being "You are free to copy andmodify this Manual."File: or1k.info, Node: Top, Next: Summary, Prev: (dir), Up: (dir)Debugging the OpenRISC 1000 with GDB************************************This file describes GDB, the GNU symbolic debugger for use with theOpenRISC 1000 processor architecture.This is the Second Edition, for GDB Version 6.8.Copyright (C) 2008 Embecosm Limited* Menu:* Summary:: Summary of GDB with OpenRISC 1000* Connecting to the Target:: Connecting to an OpenRISC 1000 Target* OpenRISC 1000 Specific Commands:: Commands just for the OpenRISC 1000* OpenRISC 1000 Example:: A small example* OpenRISC 1000 Limitations:: Known problems* Copying:: GNU General Public License sayshow you can copy and share GDB* GNU Free Documentation License:: The license for this documentation* Index:: IndexFile: or1k.info, Node: Summary, Next: Connecting to the Target, Prev: Top, Up: TopSummary of GDB with OpenRISC 1000*********************************GDB is described well in its user manual, "Debugging with GDB: The GNUSource-Level Debugger".This manual describes how to use GDB to debug C programs crosscompiled for and running on processors using the OpenRISC 1000architecture. In general GDB does not run on the actual target, but ona separate host processor. It communicates with the target via the GDB"Remote Serial Protocol" (RSP).For backwards compatibility, GDB for OpenRISC also supports thelegacy custom remote protocol, which drives the JTAG interface on theOpenRISC 1000. This is provided by adding a special target, "jtag" toGDB, allowing the debugger to connect via the JTAG interface. *NoteConnecting to the Target: Connecting to the Target.In addition the info command is extended to allow inspection ofOpenRISC 1000 Special Purpose registers, and a new command "spr" isadded to set the value of a Special Purpose Register. *Note OpenRISC1000 Specific Commands: OpenRISC 1000 Specific Commands.All the normal GDB commands should work, although hardwarewatchpoints are not tested at present. The `info registers' commandwill show the 32 general purpose registers, while the `info registersall' command will add the program counter, supervision register andexception program counter register.For those who like their debugging graphical, the `gdbtui' command isavailable (typically as `or32-uclinux-gdbtui'). GDB for OpenRISC 1000can also be run under `ddd' as follows:`ddd --debugger=or32-uclinux-gdb --gdb'* Menu:* Contributors:: Contributors to GDB for the OpenRISC 1000File: or1k.info, Node: Contributors, Up: SummaryContributors to GDB for the OpenRISC 1000=========================================The pantheon of contributors to GDB over the years is recorded in themain user manual, `Debugging with GDB: The GNU Source-Level Debugger".There is no official history of contributors to the OpenRISC 1000version. However the current author believes the original GDB 5.0 and5.3 ports were the work of:* Ivan Guzvinec and Johan Rydverg at OpenCores, who wrote the BinaryFile Descriptor library;* Alessandro Forin at Carnegie-Mellon University and Per Bothner atthe University of Wisconsin who wrote the main GDB interface; and* Mark Mlinar at Cygnus Support and Chris Ziomkowski at ASICS.ws,whowrote the OpenRISC JTAG interface.The port to GDB 6.8 is the work of Jeremy Bennett of EmbecosmLimited (jeremy.bennett@embecosm.com).Plea: If you know of anyone who has been omitted from this list,please email the current author, so the omission can be corrected,and credit given where it is due.File: or1k.info, Node: Connecting to the Target, Next: OpenRISC 1000 Specific Commands, Prev: Summary, Up: Top1 Connecting to an OpenRISC 1000 Target***************************************There are two ways to connect to an OpenRISC 1000 target with GDB.1. To hardware directly connected via a JP1 header linked to theparallel port. This uses the GDB command `target jtag'.2. Via a TCP/IP socket to a machine which has the hardware connected,or is running the architectural simulator using the standard GDB"Remote Serial Protocol". This uses the GDB commands `targetremote' or `target extended-remote'.3. Via a TCP/IP socket to a machine which has the hardware connected,or is running the architectural simulator using the customOpenRISC 1000 Remote JTAG protocol. This uses the GDB command`target jtag'.Note: This connection mechanism is deprecated. It remains forbackward compatibility only.Caution: If used with version 0.2.0 of the architecturalsimulator, Or1ksim, GDB version 6.8 requires a patch to be appliedto the architectural simulator. This should be available on theOpenCores website, or contact the author directly. Only the legacyOpenRISC 1000 Remote JTAG Protocol interface is available for thisversion of the architectural simualtor.The user is strongly recommended to use Or1ksim 0.3.0 or later,since this interfaces directly to GDB using the "Remote SerialProtocol".* Menu:* Direct JTAG Connection:: Direct connection via a JTAG JP1interface* Remote Serial Protocol Connection:: Connection via the GDB RemoteSerial Protocol Interface* Remote JTAG Connection:: Connection via the OpenRISC 1000 RemoteJTAG InterfaceFile: or1k.info, Node: Direct JTAG Connection, Next: Remote Serial Protocol Connection, Up: Connecting to the Target1.1 Direct connection via a JTAG JP1 Interface==============================================In this case the the device to which the JP1 header is connected must bespecifed to the `target jtag' command. Typically that will be theparallel printer port, so the command would be:`target jtag /dev/lp'Caution: The current author is not aware of anyone using the JP1interface. As a result this code has not been tested in the port toGDB version 6.8. Modern hardware connections are usually viainterfaces such as USB, for which the OpenRISC Remote Interfacecan be used (*note Remote JTAG Connection: Remote JTAGConnection.).File: or1k.info, Node: Remote Serial Protocol Connection, Next: Remote JTAG Connection, Prev: Direct JTAG Connection, Up: Connecting to the Target1.2 Connection via the GDB Remote Serial Protocol=================================================The usual mode of operation is through the GDB "Remote Serial Protocol"(RSP). This communicates to the target through a TCP/IP socket. Thetarget must then implement the server side of the interface to driveeither physical hardware (for example through a USB/JTAG connector) or asimulation of the hardware (such as the OpenRISC ArchitecturalSimulator).Although referred to as a _remote_ interface, the target may actuallybe on the same machine, just running in a separate process, with its ownterminal window.For example, to connect to the OpenRISC 1000 Architecturalsimulator, which is running on machine "thomas" and has been configuredto talk to GDB on port 51000, the following command would be used:`target remote thomas:51000'The target machine is specified as the machine name and port number.If the architectural simulator was running on the same machine, itsname may be omitted, thus:`target remote :51000'File: or1k.info, Node: Remote JTAG Connection, Prev: Remote Serial Protocol Connection, Up: Connecting to the Target1.3 Connection via the OpenRISC 1000 Remote JTAG Interface==========================================================Historically, GDB communicated with remote OpenRISC 1000 targets usinga customer protocol, the "OpenRISC 1000 Remote JTAG Interface".This protocol is maintained for backwards compatibility, but is nowdeprecated. It communicates to the target through a TCP/IP socket. Thetarget must then implement the client side of the interface to driveeither physical hardware (for example through a USB/JTAG connector) ora simulation of the hardware (such as the OpenRISC ArchitecturalSimulator).Although referred to as the _remote_ interface, the target mayactually be on the same machine, just running in a separate process,with its own terminal window.For example, to connect to the OpenRISC 1000 Architecturalsimulator, which is running on machine "thomas" and has been configuredto talk to GDB on port 50000, I could use the command:`target jtag jtag://thomas:50000'The target machine is specified after the jtag:// and separated fromthe target port by a colon. If the architectural simulator was runningon the same machine, just locahost would suffice as the machine name,thus:`target jtag jtag://localhost:50000'Unfortunately there are now two different flavours of the JTAGinterface used with OpenRISC 1000. The original version was created foruse with the OpenRISC 1000 System-on-Chip, ORPSoC. A new (smaller andsimpler) JTAG interface was developed by Igor Mohor in 2004, which isused on some designs.The default behavior of GDB is to use the original ORPSoC version ofthe interface for backwards compatibility. GDB can use the Igor Mohorversion by specifying for example:`target jtag jtag_mohor://localhost:50000'This interface is only available with remote connections using thelegacy OpenRISC 1000 Remote JTAG Protocol (deprecated). The direct JP1interface can support only the ORPSoC version of JTAG.The recommended approach is to use the GDB "Remote Serial Protocol"which interfaces directly to the simulator, and is independent of theJTAG implementation used.For completeness`target jtag jtag_orpsoc://localhost:50000'is provided as a synonym for:`target jtag jtag://localhost:50000'By default, establishing a connection _does not_ reset the target.This allows debugging to resume a partially complete program onconnection. If a reset is required, the keyworkd `RESET' (caseinsensitive) may be added at the end of the `target' command. Forexample:`target jtag jtag://localhost:50000 reset'Warning: The OpenRISC remote JTAG interface is not particularlyrobust. In particular dropping and reconnecting sessions does notseem to work well. This was a key factor in its replacement by thegeneric GDB Remote Serial Interface.File: or1k.info, Node: OpenRISC 1000 Specific Commands, Next: OpenRISC 1000 Example, Prev: Connecting to the Target, Up: Top2 Commands just for the OpenRISC 1000*************************************The OpenRISC 1000 has one particular feature that is difficult for GDB.GDB models target processors with a register bank and a block ofmemory. The internals of GDB assume that there are not a huge number ofregisters in total.The OpenRISC 1000 Special Purpose Registers (SPR) do not really fitwell into this structure. There are too many of them (12 groups eachwith 2000+ entries so far, with up to 32 groups permitted) to beimplemented as ordinary registers in GDB. Think what this would meanfor the command `info registers all'. However they cannot be consideredmemory, since they do not reside in the main memory map.The solution is to add two new commands to GDB to see the value of aparticular SPR and to set the value of a particular SPR.1. `info spr' is used to show the value of a SPR or group of SPRs.2. `spr' is used to set the value of an individual SPR.* Menu:* Reading SPRs:: Using the ``info spr'' command* Writing SPRs:: Using the spr commandFile: or1k.info, Node: Reading SPRs, Next: Writing SPRs, Up: OpenRISC 1000 Specific Commands2.1 Using the `info spr' Command================================The value of an SPR is read by specifying either the unique name of theSPR, or the its group and index in that group. For example the DebugReason Register (`DRR', register 21 in group 6 (Debug)) can be readusing any of the following commands:`info spr DRR'`info spr debug DRR'`info spr debug 21'`info spr 6 DRR'`info spr 6 21'In each case the output will be:`DEBUG.DRR = SPR6_21 = 0 (0x0)'It is also possible to inspect all the registers in a group. Forexample to look at all the Programmable Interrupt Controller registers(group 9), either of the following commands could be used:`info spr PIC'`info spr 9'And the output would be:`PIC.PICMR = SPR9_0 = 0 (0x9)'`PIC.PICSR = SPR9_2 = 0 (0x8)'Indicating that interrupts 0 and 4 are enabled and interrupt 4 ispending.File: or1k.info, Node: Writing SPRs, Prev: Reading SPRs, Up: OpenRISC 1000 Specific Commands2.2 Using the `spr' Command===========================The value of an SPR is written by specifying the unique name of the SPRor its group and index in the same manner as for the `info spr'command. An additional argument specifies the value to be written. Sofor example the Programmable Interrupt Controller mask register couldbe changed to enable interrupts 5 and 3 only by any of the followingcommands.`spr PICMR 0x24'`spr PIC PICMR 0x24'`spr PIC 0 0x24'`spr 9 PICMR 0x24'`spr 9 2 0x24'File: or1k.info, Node: OpenRISC 1000 Example, Next: OpenRISC 1000 Limitations, Prev: OpenRISC 1000 Specific Commands, Up: Top3 A Small Example*****************A simple "Hello World" program (what else) is used to show the basicsThis is the cannonical small program. Here is the main program andits two subprograms (added to demonstrate a meaningful backtrace).void level2() {simexit( 0 );}void level1() {level2();}main(){int i;int j;simputs( "Hello World!\n" );level1();}It is linked with a program providing the utility functions`simexit', `simputc' and `simprints'.void simexit( int rc ){__asm__ __volatile__ ( "\tl.nop\t%0" : : "K"( NOP_EXIT ));} /* simexit() */void simputc( int c ){__asm__ __volatile__ ( "\tl.nop\t%0" : : "K"( NOP_PUTC ));} /* simputc() */void simputs( char *str ){int i;for( i = 0; str[i] != '\0' ; i++ ) {simputc( (int)(str[i]) );}} /* simputs() */Finally, a small bootloader is needed, which will be placed at theOpenRISC reset vector location (0x100) to set up a stack and jump tothe main program..org 0x100 # The reset routine goes at 0x100.global _start_start:l.addi r1,r0,0x7f00 # Set SP to value 0x7f00l.addi r2,r1,0x0 # FP and SP are the samel.mfspr r3,r0,17 # Get SR valuel.ori r3,r3,0x10 # Set exception enable bitl.jal _main # Jump to main routinel.mtspr r0,r3,17 # Enable exceptions (DELAY SLOT).org 0xFFCl.nop # Guarantee the exception vector space# does not have general purpose codeThis is compiled and linked with the OpenRISC 1000 GNU toolchain.Note that the linking must specify the bootloader first and use the`-Ttext 0x0' argument.The Or1ksim architectural simulator is configured with memorystarting at location 0x0. The debugging interface is enabled by using adebug section.section debugenabled = 1gdb_enabled = 1server_port = 50000endThe architectural simulator is started in its own terminal window.If the configuration is in `rsp.cfg', then the command might be:`or32-uclinux-sim -f rsp.cfg'Reading script file from 'rsp.cfg'...Building automata... done, num uncovered: 0/213.Parsing operands data... done.Resetting memory controller.Resetting PIC.Note that no program is specified - that will be loaded from GDB.In a separate window start up GDB.`or32-uclinux-gdb'A local copy of the symbol table is needed, specified with the `file'command.Building automata... done, num uncovered: 0/216.Parsing operands data... done.GNU gdb 6.8Copyright (C) 2008 Free Software Foundation, Inc.License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>This is free software: you are free to change and redistribute it.There is NO WARRANTY, to the extent permitted by law. Type "show copying"and "show warranty" for details.This GDB was configured as "--host=i686-pc-linux-gnu --target=or32-uclinux".(gdb) `file hello'Reading symbols from /home/jeremy/svntrunk/GNU/gdb-6.8/progs_or32/hello...done.(gdb)The connection to the target (the architectural simulator) is thenestablished, using the port number given in the configuration file.(gdb) `target remote :51000'Remote debugging using :510000x00000100 in _start ()(gdb)The program of interest can now be loaded:(gdb) `load hello'Loading section .text, size 0x1290 lma 0x0Loading section .rodata, size 0xe lma 0x1290Start address 0x100, load size 4766Transfer rate: 5 KB/sec, 238 bytes/write.(gdb)The program does not immediately start running, since on opening theconnection to the target, Or1ksim stalls.All the GDB commands (including the SPR commands are available). Forexample(gdb) `bt'#0 0x00000100 in _start ()(gdb) `info spr 0 17'SYS.SR = SPR0_17 = 32769 (0x8001)(gdb)The Supervision Register shows the target is in Supervisor Mode andthat SPRs have User Mode read access._Note._ The supervision register is used to provide the value for theGDB `$ps' processor status variable, so can also be accessed as:(gdb) `print $ps'$1 = 32769(gdb)For this example set a breakpoint at the start of main and thencontinue the program(gdb) `break main'Breakpoint 1 at 0x1264: file hello.c, line 41.(gdb) `continue'Continuing.Breakpoint 1, main () at hello.c:4141 simputs( "Hello World!\n" );(gdb)It is now possible to step through the code:(gdb) `step'simputs (str=0x1290 "Hello World!\n") at utils.c:9090 for( i = 0; str[i] != '\0' ; i++ ) {(gdb) `step'91 simputc( (int)(str[i]) );(gdb) `step'simputc (c=72) at utils.c:5858 __asm__ __volatile__ ( "\tl.nop\t%0" : : "K"( NOP_PUTC ));(gdb)At this point a backtrace will show where the code has reached:(gdb) `bt'#0 simputc (c=72) at utils.c:58#1 0x000011cc in simputs (str=0x1290 "Hello World!\n") at utils.c:91#2 0x00001274 in main () at hello.c:41#3 0x00000118 in _start ()(gdb)One more step completes the call to the character output routine.Inspecting the terminal running the Or1ksim simulation, shows theoutput appearing:JTAG Proxy server started on port 50000Resetting PIC.HLet the program run to completion by giving GDB the continue command:(gdb) `continue'Continuing.Remote connection closed(gdb)With completion of the program, the terminal running Or1ksim showsits final output:Resetting PIC.Hello World!exit(0)@reset : cycles 0, insn #0@exit : cycles 215892308, insn #215891696diff : cycles 215892308, insn #215891696When execution exits (by execution of a `l.nop 1'), the connectionto the target is automatically broken as the simulator exits.File: or1k.info, Node: OpenRISC 1000 Limitations, Next: Copying, Prev: OpenRISC 1000 Example, Up: Top4 Known Problems****************There are some known problems with the current implementation1. If the OpenRISC 1000 Architecture supports hardware watchpoints,GDB will use them to implement hardware breakpoints andwatchpoints. GDB is not perfect in handling of watchpoints. It ispossible to allocate hardware watchpoints and not discover untilrunning that sufficient watchpoints are not available. It is alsopossible that GDB will report watchpoints being hit spuriously.This can be down to the assembly code having additional memoryaccesses that are not obviously reflected in the source code.2. The remote JTAG connection is not robust to being interrupted, orreconnecting. If the connection is lost due to error, then youmust restart GDB and the target server (for example the Or1ksimarchitectural simulator). Moving to the Remote Serial Protocol isintended to remedy this problem in the future.3. The OpenRISC 1000 architecture has evolved since the port of GDB5.3 in 2001. In particular the structure of the Unit Presentregister has changed and the CPU Configuration register has beenadded. The port of GDB version 6.8 uses the _current_specification of the OpenRISC 1000. This means that old clientsthat talk to the debugger may not work. In particular the Or1ksimArchitectural simulator requires a patch to work.4. The handling of watchpoints in the Or1ksim architectural simulatorwas incorrect. To work with GDB 6.8, a patch is required to fixthis problem. This is combined with the patch changing thestructure of the Unit Present and CPU Configuration registers.5. The OpenRISC 1000 architecture uses its General Purpose Register(GPR) 2 as a frame pointer register. However the `$fp' variable inGDB is not currently implemented, and will return the value of thestack pointer (GPR 1) instead.Reports of bugs are much welcomed. Please report problems through theOpenCORES tracker at `www.opencores.org/ptracker.cgi/list/or1k'.File: or1k.info, Node: Copying, Next: GNU Free Documentation License, Prev: OpenRISC 1000 Limitations, Up: TopAppendix A GNU GENERAL PUBLIC LICENSE*************************************Version 2, June 1991Copyright (C) 1989, 1991 Free Software Foundation, Inc.51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.Everyone is permitted to copy and distribute verbatim copiesof this license document, but changing it is not allowed.Preamble========The licenses for most software are designed to take away your freedomto share and change it. By contrast, the GNU General Public License isintended to guarantee your freedom to share and change freesoftware--to make sure the software is free for all its users. ThisGeneral Public License applies to most of the Free SoftwareFoundation's software and to any other program whose authors commit tousing it. 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Suchnew versions will be similar in spirit to the present version, butmay differ in detail to address new problems or concerns.Each version is given a distinguishing version number. If theProgram specifies a version number of this License which appliesto it and "any later version", you have the option of followingthe terms and conditions either of that version or of any laterversion published by the Free Software Foundation. If the Programdoes not specify a version number of this License, you may chooseany version ever published by the Free Software Foundation.10. If you wish to incorporate parts of the Program into other freeprograms whose distribution conditions are different, write to theauthor to ask for permission. For software which is copyrightedby the Free Software Foundation, write to the Free SoftwareFoundation; we sometimes make exceptions for this. Our decisionwill be guided by the two goals of preserving the free status ofall derivatives of our free software and of promoting the sharingand reuse of software generally.NO WARRANTY11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NOWARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLELAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHTHOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUTWARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUTNOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY ANDFITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THEQUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THEPROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARYSERVICING, REPAIR OR CORRECTION.12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO INWRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAYMODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BELIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL,INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE ORINABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OFDATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOUOR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANYOTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEENADVISED OF THE POSSIBILITY OF SUCH DAMAGES.END OF TERMS AND CONDITIONSHow to Apply These Terms to Your New Programs=============================================If you develop a new program, and you want it to be of the greatestpossible use to the public, the best way to achieve this is to make itfree software which everyone can redistribute and change under theseterms.To do so, attach the following notices to the program. It is safestto attach them to the start of each source file to most effectivelyconvey the exclusion of warranty; and each file should have at leastthe "copyright" line and a pointer to where the full notice is found.ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.Copyright (C) YEAR NAME OF AUTHORThis program is free software; you can redistribute it and/or modifyit under the terms of the GNU General Public License as published bythe Free Software Foundation; either version 2 of the License, or(at your option) any later version.This program is distributed in the hope that it will be useful,but WITHOUT ANY WARRANTY; without even the implied warranty ofMERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See theGNU General Public License for more details.You should have received a copy of the GNU General Public Licensealong with this program; if not, write to the Free SoftwareFoundation, Inc., 51 Franklin Street, Fifth Floor,Boston, MA 02110-1301, USA.Also add information on how to contact you by electronic and papermail.If the program is interactive, make it output a short notice likethis when it starts in an interactive mode:Gnomovision version 69, Copyright (C) YEAR NAME OF AUTHORGnomovision comes with ABSOLUTELY NO WARRANTY; for detailstype `show w'.This is free software, and you are welcome to redistribute itunder certain conditions; type `show c' for details.The hypothetical commands `show w' and `show c' should show theappropriate parts of the General Public License. Of course, thecommands you use may be called something other than `show w' and `showc'; they could even be mouse-clicks or menu items--whatever suits yourprogram.You should also get your employer (if you work as a programmer) oryour school, if any, to sign a "copyright disclaimer" for the program,if necessary. Here is a sample; alter the names:Yoyodyne, Inc., hereby disclaims all copyright interest in the program`Gnomovision' (which makes passes at compilers) written by James Hacker.SIGNATURE OF TY COON, 1 April 1989Ty Coon, President of ViceThis General Public License does not permit incorporating yourprogram into proprietary programs. If your program is a subroutinelibrary, you may consider it more useful to permit linking proprietaryapplications with the library. If this is what you want to do, use theGNU Library General Public License instead of this License.File: or1k.info, Node: GNU Free Documentation License, Next: Index, Prev: Copying, Up: TopAppendix B GNU Free Documentation License*****************************************Version 1.2, November 2002Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.Everyone is permitted to copy and distribute verbatim copiesof this license document, but changing it is not allowed.0. PREAMBLEThe purpose of this License is to make a manual, textbook, or otherfunctional and useful document "free" in the sense of freedom: toassure everyone the effective freedom to copy and redistribute it,with or without modifying it, either commercially ornoncommercially. Secondarily, this License preserves for theauthor and publisher a way to get credit for their work, while notbeing considered responsible for modifications made by others.This License is a kind of "copyleft", which means that derivativeworks of the document must themselves be free in the same sense.It complements the GNU General Public License, which is a copyleftlicense designed for free software.We have designed this License in order to use it for manuals forfree software, because free software needs free documentation: afree program should come with manuals providing the same freedomsthat the software does. But this License is not limited tosoftware manuals; it can be used for any textual work, regardlessof subject matter or whether it is published as a printed book.We recommend this License principally for works whose purpose isinstruction or reference.1. APPLICABILITY AND DEFINITIONSThis License applies to any manual or other work, in any medium,that contains a notice placed by the copyright holder saying itcan be distributed under the terms of this License. Such a noticegrants a world-wide, royalty-free license, unlimited in duration,to use that work under the conditions stated herein. The"Document", below, refers to any such manual or work. Any memberof the public is a licensee, and is addressed as "you". Youaccept the license if you copy, modify or distribute the work in away requiring permission under copyright law.A "Modified Version" of the Document means any work containing theDocument or a portion of it, either copied verbatim, or withmodifications and/or translated into another language.A "Secondary Section" is a named appendix or a front-matter sectionof the Document that deals exclusively with the relationship of thepublishers or authors of the Document to the Document's overallsubject (or to related matters) and contains nothing that couldfall directly within that overall subject. (Thus, if the Documentis in part a textbook of mathematics, a Secondary Section may notexplain any mathematics.) The relationship could be a matter ofhistorical connection with the subject or with related matters, orof legal, commercial, philosophical, ethical or political positionregarding them.The "Invariant Sections" are certain Secondary Sections whosetitles are designated, as being those of Invariant Sections, inthe notice that says that the Document is released under thisLicense. If a section does not fit the above definition ofSecondary then it is not allowed to be designated as Invariant.The Document may contain zero Invariant Sections. If the Documentdoes not identify any Invariant Sections then there are none.The "Cover Texts" are certain short passages of text that arelisted, as Front-Cover Texts or Back-Cover Texts, in the noticethat says that the Document is released under this License. AFront-Cover Text may be at most 5 words, and a Back-Cover Text maybe at most 25 words.A "Transparent" copy of the Document means a machine-readable copy,represented in a format whose specification is available to thegeneral public, that is suitable for revising the documentstraightforwardly with generic text editors or (for imagescomposed of pixels) generic paint programs or (for drawings) somewidely available drawing editor, and that is suitable for input totext formatters or for automatic translation to a variety offormats suitable for input to text formatters. A copy made in anotherwise Transparent file format whose markup, or absence ofmarkup, has been arranged to thwart or discourage subsequentmodification by readers is not Transparent. An image format isnot Transparent if used for any substantial amount of text. Acopy that is not "Transparent" is called "Opaque".Examples of suitable formats for Transparent copies include plainASCII without markup, Texinfo input format, LaTeX input format,SGML or XML using a publicly available DTD, andstandard-conforming simple HTML, PostScript or PDF designed forhuman modification. Examples of transparent image formats includePNG, XCF and JPG. Opaque formats include proprietary formats thatcan be read and edited only by proprietary word processors, SGML orXML for which the DTD and/or processing tools are not generallyavailable, and the machine-generated HTML, PostScript or PDFproduced by some word processors for output purposes only.The "Title Page" means, for a printed book, the title page itself,plus such following pages as are needed to hold, legibly, thematerial this License requires to appear in the title page. Forworks in formats which do not have any title page as such, "TitlePage" means the text near the most prominent appearance of thework's title, preceding the beginning of the body of the text.A section "Entitled XYZ" means a named subunit of the Documentwhose title either is precisely XYZ or contains XYZ in parenthesesfollowing text that translates XYZ in another language. (Here XYZstands for a specific section name mentioned below, such as"Acknowledgements", "Dedications", "Endorsements", or "History".)To "Preserve the Title" of such a section when you modify theDocument means that it remains a section "Entitled XYZ" accordingto this definition.The Document may include Warranty Disclaimers next to the noticewhich states that this License applies to the Document. TheseWarranty Disclaimers are considered to be included by reference inthis License, but only as regards disclaiming warranties: any otherimplication that these Warranty Disclaimers may have is void andhas no effect on the meaning of this License.2. VERBATIM COPYINGYou may copy and distribute the Document in any medium, eithercommercially or noncommercially, provided that this License, thecopyright notices, and the license notice saying this Licenseapplies to the Document are reproduced in all copies, and that youadd no other conditions whatsoever to those of this License. Youmay not use technical measures to obstruct or control the readingor further copying of the copies you make or distribute. However,you may accept compensation in exchange for copies. If youdistribute a large enough number of copies you must also followthe conditions in section 3.You may also lend copies, under the same conditions stated above,and you may publicly display copies.3. COPYING IN QUANTITYIf you publish printed copies (or copies in media that commonlyhave printed covers) of the Document, numbering more than 100, andthe Document's license notice requires Cover Texts, you mustenclose the copies in covers that carry, clearly and legibly, allthese Cover Texts: Front-Cover Texts on the front cover, andBack-Cover Texts on the back cover. Both covers must also clearlyand legibly identify you as the publisher of these copies. Thefront cover must present the full title with all words of thetitle equally prominent and visible. You may add other materialon the covers in addition. Copying with changes limited to thecovers, as long as they preserve the title of the Document andsatisfy these conditions, can be treated as verbatim copying inother respects.If the required texts for either cover are too voluminous to fitlegibly, you should put the first ones listed (as many as fitreasonably) on the actual cover, and continue the rest ontoadjacent pages.If you publish or distribute Opaque copies of the Documentnumbering more than 100, you must either include amachine-readable Transparent copy along with each Opaque copy, orstate in or with each Opaque copy a computer-network location fromwhich the general network-using public has access to downloadusing public-standard network protocols a complete Transparentcopy of the Document, free of added material. If you use thelatter option, you must take reasonably prudent steps, when youbegin distribution of Opaque copies in quantity, to ensure thatthis Transparent copy will remain thus accessible at the statedlocation until at least one year after the last time youdistribute an Opaque copy (directly or through your agents orretailers) of that edition to the public.It is requested, but not required, that you contact the authors ofthe Document well before redistributing any large number ofcopies, to give them a chance to provide you with an updatedversion of the Document.4. MODIFICATIONSYou may copy and distribute a Modified Version of the Documentunder the conditions of sections 2 and 3 above, provided that yourelease the Modified Version under precisely this License, withthe Modified Version filling the role of the Document, thuslicensing distribution and modification of the Modified Version towhoever possesses a copy of it. In addition, you must do thesethings in the Modified Version:A. Use in the Title Page (and on the covers, if any) a titledistinct from that of the Document, and from those ofprevious versions (which should, if there were any, be listedin the History section of the Document). You may use thesame title as a previous version if the original publisher ofthat version gives permission.B. List on the Title Page, as authors, one or more persons orentities responsible for authorship of the modifications inthe Modified Version, together with at least five of theprincipal authors of the Document (all of its principalauthors, if it has fewer than five), unless they release youfrom this requirement.C. State on the Title page the name of the publisher of theModified Version, as the publisher.D. Preserve all the copyright notices of the Document.E. Add an appropriate copyright notice for your modificationsadjacent to the other copyright notices.F. Include, immediately after the copyright notices, a licensenotice giving the public permission to use the ModifiedVersion under the terms of this License, in the form shown inthe Addendum below.G. Preserve in that license notice the full lists of InvariantSections and required Cover Texts given in the Document'slicense notice.H. Include an unaltered copy of this License.I. Preserve the section Entitled "History", Preserve its Title,and add to it an item stating at least the title, year, newauthors, and publisher of the Modified Version as given onthe Title Page. If there is no section Entitled "History" inthe Document, create one stating the title, year, authors,and publisher of the Document as given on its Title Page,then add an item describing the Modified Version as stated inthe previous sentence.J. Preserve the network location, if any, given in the Documentfor public access to a Transparent copy of the Document, andlikewise the network locations given in the Document forprevious versions it was based on. These may be placed inthe "History" section. You may omit a network location for awork that was published at least four years before theDocument itself, or if the original publisher of the versionit refers to gives permission.K. For any section Entitled "Acknowledgements" or "Dedications",Preserve the Title of the section, and preserve in thesection all the substance and tone of each of the contributoracknowledgements and/or dedications given therein.L. Preserve all the Invariant Sections of the Document,unaltered in their text and in their titles. Section numbersor the equivalent are not considered part of the sectiontitles.M. Delete any section Entitled "Endorsements". Such a sectionmay not be included in the Modified Version.N. Do not retitle any existing section to be Entitled"Endorsements" or to conflict in title with any InvariantSection.O. Preserve any Warranty Disclaimers.If the Modified Version includes new front-matter sections orappendices that qualify as Secondary Sections and contain nomaterial copied from the Document, you may at your optiondesignate some or all of these sections as invariant. To do this,add their titles to the list of Invariant Sections in the ModifiedVersion's license notice. These titles must be distinct from anyother section titles.You may add a section Entitled "Endorsements", provided it containsnothing but endorsements of your Modified Version by variousparties--for example, statements of peer review or that the texthas been approved by an organization as the authoritativedefinition of a standard.You may add a passage of up to five words as a Front-Cover Text,and a passage of up to 25 words as a Back-Cover Text, to the endof the list of Cover Texts in the Modified Version. Only onepassage of Front-Cover Text and one of Back-Cover Text may beadded by (or through arrangements made by) any one entity. If theDocument already includes a cover text for the same cover,previously added by you or by arrangement made by the same entityyou are acting on behalf of, you may not add another; but you mayreplace the old one, on explicit permission from the previouspublisher that added the old one.The author(s) and publisher(s) of the Document do not by thisLicense give permission to use their names for publicity for or toassert or imply endorsement of any Modified Version.5. COMBINING DOCUMENTSYou may combine the Document with other documents released underthis License, under the terms defined in section 4 above formodified versions, provided that you include in the combinationall of the Invariant Sections of all of the original documents,unmodified, and list them all as Invariant Sections of yourcombined work in its license notice, and that you preserve alltheir Warranty Disclaimers.The combined work need only contain one copy of this License, andmultiple identical Invariant Sections may be replaced with a singlecopy. If there are multiple Invariant Sections with the same namebut different contents, make the title of each such section uniqueby adding at the end of it, in parentheses, the name of theoriginal author or publisher of that section if known, or else aunique number. Make the same adjustment to the section titles inthe list of Invariant Sections in the license notice of thecombined work.In the combination, you must combine any sections Entitled"History" in the various original documents, forming one sectionEntitled "History"; likewise combine any sections Entitled"Acknowledgements", and any sections Entitled "Dedications". Youmust delete all sections Entitled "Endorsements."6. COLLECTIONS OF DOCUMENTSYou may make a collection consisting of the Document and otherdocuments released under this License, and replace the individualcopies of this License in the various documents with a single copythat is included in the collection, provided that you follow therules of this License for verbatim copying of each of thedocuments in all other respects.You may extract a single document from such a collection, anddistribute it individually under this License, provided you inserta copy of this License into the extracted document, and followthis License in all other respects regarding verbatim copying ofthat document.7. AGGREGATION WITH INDEPENDENT WORKSA compilation of the Document or its derivatives with otherseparate and independent documents or works, in or on a volume ofa storage or distribution medium, is called an "aggregate" if thecopyright resulting from the compilation is not used to limit thelegal rights of the compilation's users beyond what the individualworks permit. When the Document is included in an aggregate, thisLicense does not apply to the other works in the aggregate whichare not themselves derivative works of the Document.If the Cover Text requirement of section 3 is applicable to thesecopies of the Document, then if the Document is less than one halfof the entire aggregate, the Document's Cover Texts may be placedon covers that bracket the Document within the aggregate, or theelectronic equivalent of covers if the Document is in electronicform. Otherwise they must appear on printed covers that bracketthe whole aggregate.8. TRANSLATIONTranslation is considered a kind of modification, so you maydistribute translations of the Document under the terms of section4. Replacing Invariant Sections with translations requires specialpermission from their copyright holders, but you may includetranslations of some or all Invariant Sections in addition to theoriginal versions of these Invariant Sections. You may include atranslation of this License, and all the license notices in theDocument, and any Warranty Disclaimers, provided that you alsoinclude the original English version of this License and theoriginal versions of those notices and disclaimers. In case of adisagreement between the translation and the original version ofthis License or a notice or disclaimer, the original version willprevail.If a section in the Document is Entitled "Acknowledgements","Dedications", or "History", the requirement (section 4) toPreserve its Title (section 1) will typically require changing theactual title.9. TERMINATIONYou may not copy, modify, sublicense, or distribute the Documentexcept as expressly provided for under this License. Any otherattempt to copy, modify, sublicense or distribute the Document isvoid, and will automatically terminate your rights under thisLicense. However, parties who have received copies, or rights,from you under this License will not have their licensesterminated so long as such parties remain in full compliance.10. FUTURE REVISIONS OF THIS LICENSEThe Free Software Foundation may publish new, revised versions ofthe GNU Free Documentation License from time to time. Such newversions will be similar in spirit to the present version, but maydiffer in detail to address new problems or concerns. See`http://www.gnu.org/copyleft/'.Each version of the License is given a distinguishing versionnumber. If the Document specifies that a particular numberedversion of this License "or any later version" applies to it, youhave the option of following the terms and conditions either ofthat specified version or of any later version that has beenpublished (not as a draft) by the Free Software Foundation. Ifthe Document does not specify a version number of this License,you may choose any version ever published (not as a draft) by theFree Software Foundation.B.1 ADDENDUM: How to use this License for your documents========================================================To use this License in a document you have written, include a copy ofthe License in the document and put the following copyright and licensenotices just after the title page:Copyright (C) YEAR YOUR NAME.Permission is granted to copy, distribute and/or modify this documentunder the terms of the GNU Free Documentation License, Version 1.2or any later version published by the Free Software Foundation;with no Invariant Sections, no Front-Cover Texts, and no Back-CoverTexts. A copy of the license is included in the section entitled ``GNUFree Documentation License''.If you have Invariant Sections, Front-Cover Texts and Back-CoverTexts, replace the "with...Texts." line with this:with the Invariant Sections being LIST THEIR TITLES, withthe Front-Cover Texts being LIST, and with the Back-Cover Textsbeing LIST.If you have Invariant Sections without Cover Texts, or some othercombination of the three, merge those two alternatives to suit thesituation.If your document contains nontrivial examples of program code, werecommend releasing these examples in parallel under your choice offree software license, such as the GNU General Public License, topermit their use in free software.File: or1k.info, Node: Index, Prev: GNU Free Documentation License, Up: TopIndex*****
