path: root/sis.info

This is sis.info, produced by makeinfo version 6.5 from sis.texi.

This manual is for SIS (version 2.14, 21 May 2019).

   Copyright (C) 2019 Free Software Foundation, Inc.

     Permission is granted to copy, distribute and/or modify this
     document under the terms of the GNU Free Documentation License,
     Version 1.3 or any later version published by the Free Software
     Foundation; with no Invariant Sections, with no Front-Cover Texts,
     and with no Back-Cover Texts.  A copy of the license is included in
     the section entitled "GNU Free Documentation License".
INFO-DIR-SECTION Texinfo documentation system
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* sis: (sis)Invoking sis.
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File: sis.info,  Node: Top,  Next: Introduction,  Up: (dir)

SIS
***

This manual is for SIS (version 2.14, 21 May 2019).

* Menu:

* Introduction::
* Invoking sis::
* Commands ::
* Emulated Systems ::
* Multi-processing ::
* Interfacing to GDB ::
* Code coverage ::
* Building SIS ::
* GNU Free Documentation License::
* Index::


File: sis.info,  Node: Introduction,  Next: Invoking sis,  Prev: Top,  Up: Top

1 Introduction
**************

SIS is a SPARC V7/V8 and RISC-V RV32IMACFD architecture simulator.  It
consist of three main parts: an event-based simulator core, a cpu
(SPARC/RISCV) emulation module and system-specific memory and peripheral
modules.

   SIS can emulate four specific systems:

'ERC32'
     ERC32 SPARC V7 processor

'LEON2'
     LEON2 SPARC V8 processor

'LEON3'
     LEON3 SPARC V8 processor

'RISC-V'
     RISC-V (RV32IMACFD) processor

   The LEON3 and RISC-V emulation also supports SMP with up to four
processor cores.


File: sis.info,  Node: Invoking sis,  Next: Commands,  Prev: Introduction,  Up: Top

2 Invoking sis
**************

The simulator is started as follows:
     sis [options] [file]

   The following options are recognized:

'-c FILE'
     Read sis commands from FILE at startup.

'-cov'
     Enable code coverage and write a coverage file at exit.

'-d CLOCKS'
     Set the the number of CLOCKS in each time-slice for multi-processor
     simulation.  Default is 50, set lower for higher accuracy.

'-erc32'
     Emulate the SPARC V7 ERC32 processor

'-freq FREQ'
     Set frequency of emulated cpu.  This is used by the 'perf' command
     to calculated the MIPS figure for a particular configuration.  The
     frequency must be an integer indicating the frequency in MHz.

'-gdb'
     Start a gdb server, listening on port 1234.  An alternative port
     can be specified with -PORT NN.

'-leon2'
     Emulate the SPARC V8 LEON2 processor

'-leon3'
     Emulate the SPARC V8 LEON3 processor

'-m CORES'
     Enable the number of CORES (2 - 4) in a leon3 or RISC-V
     multi-processor system.

'-nfp'
     Disable the simulated FPU, so each FPU instruction will generate a
     FPU disabled trap.

'-port PORT'
     Use PORT for the gdb server.  Default is port 1234.

'-r'
     Start execution immediately without an interactive shell.  This is
     useful for automated testing.

'-riscv'
     Emulate a RISC-V RV32IMACFD processor

'-tlim DELAY'
     Used together with -R to limit the amount of simulated time that
     the simulator runs for before exiting.  The following units are
     recognized: US, MS and S.  To limit simulated time to 100 seconds,
     use: -TLIM 100 S.

'-uart1 DEVICE'
     Connect UART1 (console) of the simulator to DEVICE.  stdin/stout is
     default.
'-v'
     Increase the debug level with 1, to provide more diagnostic
     messages.  Can be added multiple times.

'file'
     The executable file to be loaded must be an SPARC or RISCV ELF
     file.  On start-up, the file is loaded into the simulated memory.


File: sis.info,  Node: Commands,  Next: Emulated Systems,  Prev: Invoking sis,  Up: Top

3 Commands
**********

Below is the description of commands that are recognized by the
simulator.  The command-line is parsed using GNU readline.  A command
history of 64 commands is maintained.  Use the up/down arrows to recall
previous commands.  For more details, see the readline documentation.

'batch FILE'

     Execute a batch file of SIS commands.

'+bp ADDRESS'
'break ADDRESS'

     Set a breakpoint at ADDRESS.

'bp'
     Print all breakpoints.

'delete NUM'
     Delete breakpoint NUM.  Use 'bp' or 'break' to see which number is
     assigned to the breakpoints.

'csr'
     Show RISC-V CSR registers

'cont [COUNT]'
     Continue execution at present position, optionally for COUNT
     instructions.

'dis [ADDR] [COUNT]'
     Disassemble [COUNT] instructions at address [ADDR].  Default values
     for COUNT is 16 and ADDR is the present program counter.

'echo STRING'
     Print STRING to the simulator window.

'float'
     Print the FPU registers

'gdb [PORT]'
     Start the gdb server interface.  Default port is 1234, but can be
     overriden using the PORT argument.  'gdb' should be started with
     'target extended-remote localhost:1234'.

'go ADDRESS [COUNT]'
     Set pc to ADDRESS and resume execution.  If COUNT is given, 'sis'
     will stop after COUNT instructions have been executed.

'help'
     Print a small help menu for the SIS commands.

'hist [TRACE_LENGTH]'

     Enable the instruction trace buffer.  The TRACE_LENGTH last
     executed instructions will be placed in the trace buffer.  A 'hist'
     command without a TRACE_LENGTH will display the trace buffer.
     Specifying a zero trace length will disable the trace buffer.

'load FILE_NAME'

     Load an ELF file into simulator memory.

'mem [ADDR] [COUNT]'

     Display memory at [ADDR] for [COUNT] bytes.  Same default values as
     for the 'dis' command.

'quit'
     Exits the simulator.

'perf [reset]'
     The 'perf' command will display various execution statistics.  A
     'perf reset' command will reset the statistics.  This can be used
     if statistics shall be calculated only over a part of the program.
     The 'run' and 'reset' command also resets the statistic
     information.

'reg [REG_NAME] [VALUE]'
     Print or set the CPU registers.  'reg' without parameters prints
     the CPU registers.  'reg' REG_NAME VALUE sets the corresponding
     register to VALUE.  Valid register names for SPARC are psr, tbr,
     wim, y, g1-g7, o0-o7 and l0-l7.  Valid register names for RISCV-V
     are mtvec, mstatus, pc, ra, sp, gp, tp, t0-t6, s0-s11 and a0-a7.

'reset'
     Perform a power-on reset.  This command is equal to 'run 0'.

'run [COUNT]'

     Reset the simulator and start execution from the entry point of the
     loaded ELF file.  If an instruction count is given (COUNT), the
     simulator will stop after the specified number of instructions.
     The event queue is emptied but any set breakpoints remain.

'step'

     Execute one instruction and print it to the simulator console.
     Equal to command 'trace 1'

'sym'

     List symbols and corresponding addresses in the loaded program.

'trace [COUNT]'

     Resume the simulator at the present position and print each execute
     instruction executes.  If an instruction count is given (COUNT),
     the simulator will stop after the specified number of instructions.

'wmem ADDR DATA'
     Write DATA to memory at ADDR.  Data is written as a 32-bit word.

'wp'
     Print all watchpoints

'+wpr ADDRESS'
     Adds an read watchpoint at address <address>.

'-wpr NUM'
     Delete read watchpoint NUM.  Use WP to see which number is assigned
     to the watchpoints.

'+wpw ADDRESS'
'watch ADDRESS'
     Adds an write watchpoint at ADDRESS.

'-wpw NUM'

     Delete write watchpoint NUM.  Use 'wp' to see which number is
     assigned to the watchpoints.

   Typing a 'Ctrl-C' will interrupt a running simulator.

   Short forms of the commands are allowed, e.g 'c' 'co' or 'con' are
all interpreted as 'cont'.


File: sis.info,  Node: Emulated Systems,  Next: Multi-processing,  Prev: Commands,  Up: Top

4 Emulated Systems
******************

'sis' is capable of emulating four different processor systems:

'ERC32'
     ERC32 SPARC V7 processor

'LEON2'
     LEON2 SPARC V8 processor

'LEON3'
     LEON3 SPARC V8 processor

'RISC-V'
     RISC-V (RV32IMACFD) processor

   The following sections outline the emulation characteristics of the
four supported systems.

4.1 ERC32 SPARC V7 processor
============================

The radiation-hard ERC32 processor was developed by ESA in the mid-90's
for critical space application.  It was used in the control computer for
the International Space Station (ISS) and also in the ATV re-supply ship
for the ISS. The sub-sequent single-chip ERC32SC was used in a multitude
of satellites, launchers and interplanetary probes, and is still being
manufactured by Atmel.  See the ESA ERC32 page
(http://http://microelectronics.esa.int/erc32/index.html) for more
technical documetation.

   Sis emulates the original three-chip version of the ERC32 processor,
consisting of the integer unit (IU), floating-point unit (FPU) and the
memort controller (MEC). The IU is based on the Cypress CY601 SPARC V7
processor, while the FPU is based on the Meiko FPU. The MEC implements
various peripheral functions and a memory controller.  The single-chip
verion of ERC32 (ERC32SC/TSC695F) is functionally identical to the
original chip-set, but can operate at a higher frequency (25 MHz)

The following functions of the ERC32 are emulated by sis:

   * IU & FPU with accurate timing
   * UART A & B
   * Real-time clock
   * General purpose timer
   * Interrupt controller
   * Breakpoint register
   * Watchpoint register
   * 16 Mbyte ROM
   * 16 Mbyte RAM

4.1.1 IU and FPU instruction timing.
------------------------------------

The simulator provides cycle true simulation for ERC32.  The following
table shows the emulated instruction timing for IU & FPU:

Instruction         Cycles
-----------------------------
jmpl, rett          2
load                2
store               3
load double         3
store double        4
other integer ops   1
fabs                2
fadds               4
faddd               4
fcmps               4
fcmpd               4
fdivs               20
fdivd               35
fmovs               2
fmuls               5
fmuld               9
fnegs               2
fsqrts              37
fsqrtd              65
fsubs               4
fsubd               4
fdtoi               7
fdots               3
fitos               6
fitod               6
fstoi               6
fstod               2

   The parallel operation between the IU and FPU is modelled.  This
means that a FPU instruction will execute in parallel with other
instructions as long as no data or resource dependency is detected.  See
the 90C602E data sheet for the various types of dependencies.  Tracing
using the 'trace' command will display the current simulator time in the
left column.  This time indicates when the instruction is fetched.  If a
dependency is detected, the following fetch will be delayed until the
conflict is resolved.

   The load dependency in the IU is also modelled - if the destination
register of a load instruction is used by the following instruction, an
idle cycle is inserted.

4.1.2 UART A and B
------------------

UART A is by default connected to the console, while UART B is disabled.
Both UARTs can be connected to any file/device using the -uart1 and
-uart2 options at start-up.  The following registers are implemented:

Register                                    Address
------------------------------------------------------
UART A RX and TX register                   0x01f800e0
UART B RX and TX register                   0x01f800e4
UART status register                        0x01f800e8

   The UARTs generate interrupt 4 and 5 after each received or
transmitted character.  The error interrupt is generated if overflow
occurs - other errors cannot occur.

4.1.3 Real-time clock and general purpose timer A
-------------------------------------------------

The following registers are implemented:

Register                                    Address
------------------------------------------------------
Real-time clock timer                       0x01f80080
Real-time clock scaler program register     0x01f80084
Real-time clock counter program register    0x01f80080
General purpose timer                       0x01f80088
Real-time clock scaler program register     0x01f8008c
General purpose timer counter register      0x01f80088
Timer control register                      0x01f80098

4.1.4 Interrupt controller
--------------------------

The interrupt controller is implemented as in the MEC specification with
the exception of the interrupt shape register.  Since external
interrupts are not possible, the interrupt shape register is not
implemented.  The only internal interrupts that are generated are the
real-time clock, the general purpose timer and UARTs.  However, all 15
interrupts can be tested via the interrupt force register.

   The following registers are implemented:

Register                                    Address
------------------------------------------------------
Interrupt pending register                  0x01f80048
Interrupt mask register                     0x01f8004c
Interrupt clear register                    0x01f80050
Interrupt force register                    0x01f80054

4.1.5 System fault status registers
-----------------------------------

The system fault status register and fist failing address register are
implemented and updated accordingly.  Implemented registers are:

Register                                    Address
------------------------------------------------------
System fault status register                0x01f800a0
First failing address register              0x01f800a4

4.1.6 Memory interface
----------------------

The following memory areas are valid for the ERC32 simulator:

Register                                    Address
------------------------------------------------------------------
0x00000000 - 0x01000000                     ROM (16 Mbyte)
0x02000000 - 0x03000000                     RAM (16 Mbyte)
0x01f80000 - 0x01f800ff                     MEC registers

   Access to unimplemented MEC registers or non-existing memory will
result in a memory exception trap.

   The memory configuration register is used to define available memory
in the system.  The fields RSIZ and PSIZ are used to set RAM and ROM
size, the remaining fields are not used.  NOTE: after reset, the MEC is
set to decode 4 Kbyte of ROM and 256 Kbyte of RAM. The memory
configuration register has to be updated to reflect the available
memory.

   The waitstate configuration register is used to generate waitstates.
This register must also be updated with the correct configuration after
reset.

   The memory protection scheme is implemented - it is enabled through
bit 3 in the MEC control register.

   The following registers are implemented:

Register                                    Address
-------------------------------------------------------------
MEC control register                        0x01f80000
Memory control register                     0x01f80010
Waitstate configuration register            0x01f80018
Memory access register 0                    0x01f80020
Memory access register 1                    0x01f80024

4.1.7 Watchdog
--------------

The watchdog is implemented as in the specification.  The input clock is
always the system clock regardless of WDCS bit in MEC configuration
register.

   The following registers are implemented:

Register                                    Address
-------------------------------------------------------------
Watchdog program/acknowledge register       0x01f80060
Watchdog trap door set register             0x01f80064

4.1.8 Software reset register
-----------------------------

Implemented as in the specification (0x01f800004, write-only).

4.1.9 Power-down mode
---------------------

The power-down register (0x01f800008) is implemented as in the
specification.  During power-down, the simulator skips time until next
event in the event queue.  Ctrl-C in the simulator window will exit the
power-down mode.

4.1.10 MEC control register
---------------------------

The following bits are implemented in the MEC control register:

Bit     Name   Function
-----------------------------------------------
0       PRD    Power-down mode enable
1       SWR    Soft reset enable
2       APR    Access protection enable

4.2 LEON2 emulation
===================

In LEON2 mode, SIS emulates a LEON2 system as defined in the LEON2 IP
manual.  The emulated system includes the LEON2 standard peripherals, 16
Mbyte ROM and 16 Mbyte RAM. The SPARC emulation supports an FPU but not
the LEON2 MMU.

   To start sis in LEON2 mode, use the -leon2 switch.

4.2.1 LEON2 peripherals
-----------------------

SIS emulates one LEON2 UART, the interrupt controller and the timer
unit.  The interrupt controller is implemented as described in the LEON2
IP manual, with the exception of the interrupt level register.
Secondary interrupts are not supported.  The timer unit is configured
with two timers and separate interrupts (8 and 9).  The scaler is
configured to 16 bits, while the counters are 32 bits.  The UART
generates interrupt 3.

4.2.2 Memory interface
----------------------

The following memory areas are valid for LEON2:

Address                                     Type
------------------------------------------------------------------
0x00000000 - 0x01000000                     ROM (16 Mbyte)
0x40000000 - 0x41000000                     RAM (16 Mbyte)
0x80000000 - 0x80000100                     APB bus

   Access to non-existing memory will result in a memory exception trap.

4.2.3 Power-down mode
---------------------

The LEON2 power-down register (0x80000018) is supported.  When
power-down is entered, time is skipped forward until the next event in
the event queue.  A Ctrl-C in the simulator window will exit the
power-down mode.

4.3 LEON3 emulation
===================

In LEON3 mode, SIS emulates a LEON3 system as defined in the GRLIP IP
manual.  The emulated system includes the standard peripherals such as
APBUART, GPTIMER, IRQMP and SRCTRL. The emulated system includes 16
Mbyte ROM and 16 Mbyte RAM. The SPARC emulation supports an FPU but not
the LEON3 MMU.

   To start sis in LEON3 mode, use the -leon3 switch.

4.3.1 LEON3 peripherals
-----------------------

The following IP cores from GRLIB are emulated in LEON3 mode:

IP Core                     Address        Interrupt
-------------------------------------------------------
APBMAST                     0x80000000     -
APBUART                     0x80000100     3
IRQMP                       0x80000200     -
GPTIMER                     0x80000300     8, 9

4.3.2 Memory interface
----------------------

The following memory areas are valid for LEON3:

Address                                     Type
------------------------------------------------------------------
0x00000000 - 0x01000000                     ROM (16 Mbyte)
0x40000000 - 0x41000000                     RAM (16 Mbyte)
0x80000000 - 0x81000000                     APB bus
0xFFFFF000 - 0xFFFFFFFF                     AHB plug&play

   Access to non-existing memory will result in a memory exception trap.

4.3.3 Power-down mode
---------------------

The LEON3 power-down register (%ars19) is supported.  When power-down is
entered, time is skipped forward until the next event in the event
queue.  A Ctrl-C in the simulator window will exit the power-down mode.

4.4 RISC-V emulation
====================

In RISC-V mode, SIS emulates a RV32IMACFD processor as defined in the
RISC-V specification 1.9.  The RISC-V procssor is attached to an
identical GRLIB sub-system as when LEON3 is emulated.

   To start sis in RISC-V mode, use the -riscv switch.

4.4.1 Power-down mode
---------------------

The RISC-V power-down feature (WFI) is supported.  When power-down is
entered, time is skipped forward until the next event in the event
queue.  Ctrl-C in the simulator window will exit the power-down mode.

4.4.2 Code coverage
-------------------

Code coverage is currently only supported for 32-bit instructions, i.e.
the C-extension can not be used when code coverage is measured.

4.4.3 RISC-V 64-bit timer
-------------------------

The standard RISC-V 64-bit timer is provided and can be read through the
time and timeh CSR. The timer does not generare any interrupt and the
timecmp register is not implemented.


File: sis.info,  Node: Multi-processing,  Next: Interfacing to GDB,  Prev: Emulated Systems,  Up: Top

5 Multi-processing
******************

When emulating a LEON3 or RISC-V processor, SIS can emulate up to four
cores in the target system (SMP). The cores are simulated in a
round-robin fashion with a time-slice of 50 clocks.  Shorter or longer
time-slices can be selected using -d <clocks>.

   To start SIS with SMP, use the switch -m <n> when starting the
simulator where n can be 2 - 4.


File: sis.info,  Node: Interfacing to GDB,  Next: Code coverage,  Prev: Multi-processing,  Up: Top

6 Interfacing to GDB
********************

SIS can be connected to gdb through a network socket using the gdb
remote interface.  Either start SIS with -gdb, or issue the 'gdb'
command inside SIS, and connect gdb with 'target extended-remote
localhost:1234'.  The port can be changed using the -port option.


File: sis.info,  Node: Code coverage,  Next: Building SIS,  Prev: Interfacing to GDB,  Up: Top

7 Code coverage
***************

Code coverage data will be produce if sis is started with the -cov
switch.  The coverage data will be stored in a file name same as the
file used with the load command, appended with .cov.  For instance, if
sis is run with hello.exe, the coverage data will be stored in
hello.exe.cov.  The coverage file is created when the simulator is
exited.

   The coverage file data consists of a starting address, and a number
of coverage points indicating incremental 32-bit word addresses:

   0x40000000 0 0 0 19 9 1 1 1 1 0 .....

   The coverage points are in hexadecimal format.  Bit 0 (lsb) indicates
an executed instruction.  Bit 3 indicates taken branch and bit 4
indicates an untaken branch.  Bits 2 and 3 are currently not used.

   For RISC-V, code coverage is only supported for 32-bit instructions,
i.e.  the C-extension can not be used when code coverage is measured.


File: sis.info,  Node: Building SIS,  Next: GNU Free Documentation License,  Prev: Code coverage,  Up: Top

8 Building SIS
**************

SIS uses the GNU autoconf system, and can simply be build using
'./configure' followed by 'make'.  To build a PDF version of the manual,
do 'make sis.pdf'.


File: sis.info,  Node: GNU Free Documentation License,  Next: Index,  Prev: Building SIS,  Up: Top

Appendix A GNU Free Documentation License
*****************************************

                     Version 1.3, 3 November 2008

     Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
     <http://fsf.org/>

     Everyone is permitted to copy and distribute verbatim copies
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     The purpose of this License is to make a manual, textbook, or other
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     assure everyone the effective freedom to copy and redistribute it,
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     being considered responsible for modifications made by others.

     This License is a kind of "copyleft", which means that derivative
     works of the document must themselves be free in the same sense.
     It complements the GNU General Public License, which is a copyleft
     license designed for free software.

     We have designed this License in order to use it for manuals for
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     free program should come with manuals providing the same freedoms
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     You may also lend copies, under the same conditions stated above,
     and you may publicly display copies.

  3. COPYING IN QUANTITY

     If you publish printed copies (or copies in media that commonly
     have printed covers) of the Document, numbering more than 100, and
     the Document's license notice requires Cover Texts, you must
     enclose the copies in covers that carry, clearly and legibly, all
     these Cover Texts: Front-Cover Texts on the front cover, and
     Back-Cover Texts on the back cover.  Both covers must also clearly
     and legibly identify you as the publisher of these copies.  The
     front cover must present the full title with all words of the title
     equally prominent and visible.  You may add other material on the
     covers in addition.  Copying with changes limited to the covers, as
     long as they preserve the title of the Document and satisfy these
     conditions, can be treated as verbatim copying in other respects.

     If the required texts for either cover are too voluminous to fit
     legibly, you should put the first ones listed (as many as fit
     reasonably) on the actual cover, and continue the rest onto
     adjacent pages.

     If you publish or distribute Opaque copies of the Document
     numbering more than 100, you must either include a machine-readable
     Transparent copy along with each Opaque copy, or state in or with
     each Opaque copy a computer-network location from which the general
     network-using public has access to download using public-standard
     network protocols a complete Transparent copy of the Document, free
     of added material.  If you use the latter option, you must take
     reasonably prudent steps, when you begin distribution of Opaque
     copies in quantity, to ensure that this Transparent copy will
     remain thus accessible at the stated location until at least one
     year after the last time you distribute an Opaque copy (directly or
     through your agents or retailers) of that edition to the public.

     It is requested, but not required, that you contact the authors of
     the Document well before redistributing any large number of copies,
     to give them a chance to provide you with an updated version of the
     Document.

  4. MODIFICATIONS

     You may copy and distribute a Modified Version of the Document
     under the conditions of sections 2 and 3 above, provided that you
     release the Modified Version under precisely this License, with the
     Modified Version filling the role of the Document, thus licensing
     distribution and modification of the Modified Version to whoever
     possesses a copy of it.  In addition, you must do these things in
     the Modified Version:

       A. Use in the Title Page (and on the covers, if any) a title
          distinct from that of the Document, and from those of previous
          versions (which should, if there were any, be listed in the
          History section of the Document).  You may use the same title
          as a previous version if the original publisher of that
          version gives permission.

       B. List on the Title Page, as authors, one or more persons or
          entities responsible for authorship of the modifications in
          the Modified Version, together with at least five of the
          principal authors of the Document (all of its principal
          authors, if it has fewer than five), unless they release you
          from this requirement.

       C. State on the Title page the name of the publisher of the
          Modified Version, as the publisher.

       D. Preserve all the copyright notices of the Document.

       E. Add an appropriate copyright notice for your modifications
          adjacent to the other copyright notices.

       F. Include, immediately after the copyright notices, a license
          notice giving the public permission to use the Modified
          Version under the terms of this License, in the form shown in
          the Addendum below.

       G. Preserve in that license notice the full lists of Invariant
          Sections and required Cover Texts given in the Document's
          license 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, new
          authors, and publisher of the Modified Version as given on the
          Title Page.  If there is no section Entitled "History" in the
          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 in the
          previous sentence.

       J. Preserve the network location, if any, given in the Document
          for public access to a Transparent copy of the Document, and
          likewise the network locations given in the Document for
          previous versions it was based on.  These may be placed in the
          "History" section.  You may omit a network location for a work
          that was published at least four years before the Document
          itself, or if the original publisher of the version it refers
          to gives permission.

       K. For any section Entitled "Acknowledgements" or "Dedications",
          Preserve the Title of the section, and preserve in the section
          all the substance and tone of each of the contributor
          acknowledgements and/or dedications given therein.

       L. Preserve all the Invariant Sections of the Document, unaltered
          in their text and in their titles.  Section numbers or the
          equivalent are not considered part of the section titles.

       M. Delete any section Entitled "Endorsements".  Such a section
          may 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 Invariant
          Section.

       O. Preserve any Warranty Disclaimers.

     If the Modified Version includes new front-matter sections or
     appendices that qualify as Secondary Sections and contain no
     material copied from the Document, you may at your option designate
     some or all of these sections as invariant.  To do this, add their
     titles to the list of Invariant Sections in the Modified Version's
     license notice.  These titles must be distinct from any other
     section titles.

     You may add a section Entitled "Endorsements", provided it contains
     nothing but endorsements of your Modified Version by various
     parties--for example, statements of peer review or that the text
     has been approved by an organization as the authoritative
     definition 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 end of
     the list of Cover Texts in the Modified Version.  Only one passage
     of Front-Cover Text and one of Back-Cover Text may be added by (or
     through arrangements made by) any one entity.  If the Document
     already includes a cover text for the same cover, previously added
     by you or by arrangement made by the same entity you are acting on
     behalf of, you may not add another; but you may replace the old
     one, on explicit permission from the previous publisher that added
     the old one.

     The author(s) and publisher(s) of the Document do not by this
     License give permission to use their names for publicity for or to
     assert or imply endorsement of any Modified Version.

  5. COMBINING DOCUMENTS

     You may combine the Document with other documents released under
     this License, under the terms defined in section 4 above for
     modified versions, provided that you include in the combination all
     of the Invariant Sections of all of the original documents,
     unmodified, and list them all as Invariant Sections of your
     combined work in its license notice, and that you preserve all
     their Warranty Disclaimers.

     The combined work need only contain one copy of this License, and
     multiple identical Invariant Sections may be replaced with a single
     copy.  If there are multiple Invariant Sections with the same name
     but different contents, make the title of each such section unique
     by adding at the end of it, in parentheses, the name of the
     original author or publisher of that section if known, or else a
     unique number.  Make the same adjustment to the section titles in
     the list of Invariant Sections in the license notice of the
     combined work.

     In the combination, you must combine any sections Entitled
     "History" in the various original documents, forming one section
     Entitled "History"; likewise combine any sections Entitled
     "Acknowledgements", and any sections Entitled "Dedications".  You
     must delete all sections Entitled "Endorsements."

  6. COLLECTIONS OF DOCUMENTS

     You may make a collection consisting of the Document and other
     documents released under this License, and replace the individual
     copies of this License in the various documents with a single copy
     that is included in the collection, provided that you follow the
     rules of this License for verbatim copying of each of the documents
     in all other respects.

     You may extract a single document from such a collection, and
     distribute it individually under this License, provided you insert
     a copy of this License into the extracted document, and follow this
     License in all other respects regarding verbatim copying of that
     document.

  7. AGGREGATION WITH INDEPENDENT WORKS

     A compilation of the Document or its derivatives with other
     separate and independent documents or works, in or on a volume of a
     storage or distribution medium, is called an "aggregate" if the
     copyright resulting from the compilation is not used to limit the
     legal rights of the compilation's users beyond what the individual
     works permit.  When the Document is included in an aggregate, this
     License does not apply to the other works in the aggregate which
     are not themselves derivative works of the Document.

     If the Cover Text requirement of section 3 is applicable to these
     copies of the Document, then if the Document is less than one half
     of the entire aggregate, the Document's Cover Texts may be placed
     on covers that bracket the Document within the aggregate, or the
     electronic equivalent of covers if the Document is in electronic
     form.  Otherwise they must appear on printed covers that bracket
     the whole aggregate.

  8. TRANSLATION

     Translation is considered a kind of modification, so you may
     distribute translations of the Document under the terms of section
     4.  Replacing Invariant Sections with translations requires special
     permission from their copyright holders, but you may include
     translations of some or all Invariant Sections in addition to the
     original versions of these Invariant Sections.  You may include a
     translation of this License, and all the license notices in the
     Document, and any Warranty Disclaimers, provided that you also
     include the original English version of this License and the
     original versions of those notices and disclaimers.  In case of a
     disagreement between the translation and the original version of
     this License or a notice or disclaimer, the original version will
     prevail.

     If a section in the Document is Entitled "Acknowledgements",
     "Dedications", or "History", the requirement (section 4) to
     Preserve its Title (section 1) will typically require changing the
     actual title.

  9. TERMINATION

     You may not copy, modify, sublicense, or distribute the Document
     except as expressly provided under this License.  Any attempt
     otherwise to copy, modify, sublicense, or distribute it is void,
     and will automatically terminate your rights under this License.

     However, if you cease all violation of this License, then your
     license from a particular copyright holder is reinstated (a)
     provisionally, unless and until the copyright holder explicitly and
     finally terminates your license, and (b) permanently, if the
     copyright holder fails to notify you of the violation by some
     reasonable means prior to 60 days after the cessation.

     Moreover, your license from a particular copyright holder is
     reinstated permanently if the copyright holder notifies you of the
     violation by some reasonable means, this is the first time you have
     received notice of violation of this License (for any work) from
     that copyright holder, and you cure the violation prior to 30 days
     after your receipt of the notice.

     Termination of your rights under this section does not terminate
     the licenses of parties who have received copies or rights from you
     under this License.  If your rights have been terminated and not
     permanently reinstated, receipt of a copy of some or all of the
     same material does not give you any rights to use it.

  10. FUTURE REVISIONS OF THIS LICENSE

     The Free Software Foundation may publish new, revised versions of
     the GNU Free Documentation License from time to time.  Such new
     versions will be similar in spirit to the present version, but may
     differ in detail to address new problems or concerns.  See
     <http://www.gnu.org/copyleft/>.

     Each version of the License is given a distinguishing version
     number.  If the Document specifies that a particular numbered
     version of this License "or any later version" applies to it, you
     have the option of following the terms and conditions either of
     that specified version or of any later version that has been
     published (not as a draft) by the Free Software Foundation.  If the
     Document does not specify a version number of this License, you may
     choose any version ever published (not as a draft) by the Free
     Software Foundation.  If the Document specifies that a proxy can
     decide which future versions of this License can be used, that
     proxy's public statement of acceptance of a version permanently
     authorizes you to choose that version for the Document.

  11. RELICENSING

     "Massive Multiauthor Collaboration Site" (or "MMC Site") means any
     World Wide Web server that publishes copyrightable works and also
     provides prominent facilities for anybody to edit those works.  A
     public wiki that anybody can edit is an example of such a server.
     A "Massive Multiauthor Collaboration" (or "MMC") contained in the
     site means any set of copyrightable works thus published on the MMC
     site.

     "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
     license published by Creative Commons Corporation, a not-for-profit
     corporation with a principal place of business in San Francisco,
     California, as well as future copyleft versions of that license
     published by that same organization.

     "Incorporate" means to publish or republish a Document, in whole or
     in part, as part of another Document.

     An MMC is "eligible for relicensing" if it is licensed under this
     License, and if all works that were first published under this
     License somewhere other than this MMC, and subsequently
     incorporated in whole or in part into the MMC, (1) had no cover
     texts or invariant sections, and (2) were thus incorporated prior
     to November 1, 2008.

     The operator of an MMC Site may republish an MMC contained in the
     site under CC-BY-SA on the same site at any time before August 1,
     2009, provided the MMC is eligible for relicensing.

ADDENDUM: How to use this License for your documents
====================================================

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:

       Copyright (C)  YEAR  YOUR NAME.
       Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version 1.3
       or any later version published by the Free Software Foundation;
       with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
       Texts.  A copy of the license is included in the section entitled ``GNU
       Free Documentation License''.

   If you have Invariant Sections, Front-Cover Texts and Back-Cover
Texts, replace the "with...Texts."  line with this:

         with the Invariant Sections being LIST THEIR TITLES, with
         the Front-Cover Texts being LIST, and with the Back-Cover Texts
         being LIST.

   If you have Invariant Sections without Cover Texts, or some other
combination of the three, merge those two alternatives to suit the
situation.

   If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of free
software license, such as the GNU General Public License, to permit
their use in free software.


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