[BACK]Return to gforth.ds CVS log [TXT] [DIR] Up to [gforth] / gforth

Diff for /gforth/Attic/gforth.ds between versions 1.17 and 1.21

version 1.17, 1995/09/15 14:52:51 version 1.21, 1995/11/07 18:06:41
Line 9 Line 9
 @ifinfo  @ifinfo
 This file documents Gforth 0.1  This file documents Gforth 0.1
   
 Copyright @copyright{} 1994 Gforth Development Group  Copyright @copyright{} 1995 Free Software Foundation, Inc.
   
      Permission is granted to make and distribute verbatim copies of       Permission is granted to make and distribute verbatim copies of
      this manual provided the copyright notice and this permission notice       this manual provided the copyright notice and this permission notice
Line 49  Copyright @copyright{} 1994 Gforth Devel Line 49  Copyright @copyright{} 1994 Gforth Devel
 @comment  The following two commands start the copyright page.  @comment  The following two commands start the copyright page.
 @page  @page
 @vskip 0pt plus 1filll  @vskip 0pt plus 1filll
 Copyright @copyright{} 1994 Gforth Development Group  Copyright @copyright{} 1995 Free Software Foundation, Inc.
   
 @comment !! Published by ... or You can get a copy of this manual ...  @comment !! Published by ... or You can get a copy of this manual ...
   
Line 75  Copyright @copyright{} 1994 Gforth Devel Line 75  Copyright @copyright{} 1994 Gforth Devel
 @node Top, License, (dir), (dir)  @node Top, License, (dir), (dir)
 @ifinfo  @ifinfo
 Gforth is a free implementation of ANS Forth available on many  Gforth is a free implementation of ANS Forth available on many
 personal machines. This manual corresponds to version 0.0.  personal machines. This manual corresponds to version 0.1.
 @end ifinfo  @end ifinfo
   
 @menu  @menu
Line 95  personal machines. This manual correspon Line 95  personal machines. This manual correspon
 @end menu  @end menu
   
 @node License, Goals, Top, Top  @node License, Goals, Top, Top
 @unnumbered License  @unnumbered GNU GENERAL PUBLIC LICENSE
 !! Insert GPL here  @center Version 2, June 1991
   
   @display
   Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
   675 Mass Ave, Cambridge, MA 02139, USA
   
   Everyone is permitted to copy and distribute verbatim copies
   of this license document, but changing it is not allowed.
   @end display
   
   @unnumberedsec Preamble
   
     The licenses for most software are designed to take away your
   freedom to share and change it.  By contrast, the GNU General Public
   License is intended to guarantee your freedom to share and change free
   software---to make sure the software is free for all its users.  This
   General Public License applies to most of the Free Software
   Foundation's software and to any other program whose authors commit to
   using it.  (Some other Free Software Foundation software is covered by
   the GNU Library General Public License instead.)  You can apply it to
   your programs, too.
   
     When we speak of free software, we are referring to freedom, not
   price.  Our General Public Licenses are designed to make sure that you
   have the freedom to distribute copies of free software (and charge for
   this service if you wish), that you receive source code or can get it
   if you want it, that you can change the software or use pieces of it
   in new free programs; and that you know you can do these things.
   
     To protect your rights, we need to make restrictions that forbid
   anyone to deny you these rights or to ask you to surrender the rights.
   These restrictions translate to certain responsibilities for you if you
   distribute copies of the software, or if you modify it.
   
     For example, if you distribute copies of such a program, whether
   gratis or for a fee, you must give the recipients all the rights that
   you have.  You must make sure that they, too, receive or can get the
   source code.  And you must show them these terms so they know their
   rights.
   
     We protect your rights with two steps: (1) copyright the software, and
   (2) offer you this license which gives you legal permission to copy,
   distribute and/or modify the software.
   
     Also, for each author's protection and ours, we want to make certain
   that everyone understands that there is no warranty for this free
   software.  If the software is modified by someone else and passed on, we
   want its recipients to know that what they have is not the original, so
   that any problems introduced by others will not reflect on the original
   authors' reputations.
   
     Finally, any free program is threatened constantly by software
   patents.  We wish to avoid the danger that redistributors of a free
   program will individually obtain patent licenses, in effect making the
   program proprietary.  To prevent this, we have made it clear that any
   patent must be licensed for everyone's free use or not licensed at all.
   
     The precise terms and conditions for copying, distribution and
   modification follow.
   
   @iftex
   @unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
   @end iftex
   @ifinfo
   @center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
   @end ifinfo
   
   @enumerate 0
   @item
   This License applies to any program or other work which contains
   a notice placed by the copyright holder saying it may be distributed
   under the terms of this General Public License.  The ``Program'', below,
   refers to any such program or work, and a ``work based on the Program''
   means either the Program or any derivative work under copyright law:
   that is to say, a work containing the Program or a portion of it,
   either verbatim or with modifications and/or translated into another
   language.  (Hereinafter, translation is included without limitation in
   the term ``modification''.)  Each licensee is addressed as ``you''.
   
   Activities other than copying, distribution and modification are not
   covered by this License; they are outside its scope.  The act of
   running the Program is not restricted, and the output from the Program
   is covered only if its contents constitute a work based on the
   Program (independent of having been made by running the Program).
   Whether that is true depends on what the Program does.
   
   @item
   You may copy and distribute verbatim copies of the Program's
   source code as you receive it, in any medium, provided that you
   conspicuously and appropriately publish on each copy an appropriate
   copyright notice and disclaimer of warranty; keep intact all the
   notices that refer to this License and to the absence of any warranty;
   and give any other recipients of the Program a copy of this License
   along with the Program.
   
   You may charge a fee for the physical act of transferring a copy, and
   you may at your option offer warranty protection in exchange for a fee.
   
   @item
   You may modify your copy or copies of the Program or any portion
   of it, thus forming a work based on the Program, and copy and
   distribute such modifications or work under the terms of Section 1
   above, provided that you also meet all of these conditions:
   
   @enumerate a
   @item
   You must cause the modified files to carry prominent notices
   stating that you changed the files and the date of any change.
   
   @item
   You must cause any work that you distribute or publish, that in
   whole or in part contains or is derived from the Program or any
   part thereof, to be licensed as a whole at no charge to all third
   parties under the terms of this License.
   
   @item
   If the modified program normally reads commands interactively
   when run, you must cause it, when started running for such
   interactive use in the most ordinary way, to print or display an
   announcement including an appropriate copyright notice and a
   notice that there is no warranty (or else, saying that you provide
   a warranty) and that users may redistribute the program under
   these conditions, and telling the user how to view a copy of this
   License.  (Exception: if the Program itself is interactive but
   does not normally print such an announcement, your work based on
   the Program is not required to print an announcement.)
   @end enumerate
   
   These requirements apply to the modified work as a whole.  If
   identifiable sections of that work are not derived from the Program,
   and can be reasonably considered independent and separate works in
   themselves, then this License, and its terms, do not apply to those
   sections when you distribute them as separate works.  But when you
   distribute the same sections as part of a whole which is a work based
   on the Program, the distribution of the whole must be on the terms of
   this License, whose permissions for other licensees extend to the
   entire whole, and thus to each and every part regardless of who wrote it.
   
   Thus, it is not the intent of this section to claim rights or contest
   your rights to work written entirely by you; rather, the intent is to
   exercise the right to control the distribution of derivative or
   collective works based on the Program.
   
   In addition, mere aggregation of another work not based on the Program
   with the Program (or with a work based on the Program) on a volume of
   a storage or distribution medium does not bring the other work under
   the scope of this License.
   
   @item
   You may copy and distribute the Program (or a work based on it,
   under Section 2) in object code or executable form under the terms of
   Sections 1 and 2 above provided that you also do one of the following:
   
   @enumerate a
   @item
   Accompany it with the complete corresponding machine-readable
   source code, which must be distributed under the terms of Sections
   1 and 2 above on a medium customarily used for software interchange; or,
   
   @item
   Accompany it with a written offer, valid for at least three
   years, to give any third party, for a charge no more than your
   cost of physically performing source distribution, a complete
   machine-readable copy of the corresponding source code, to be
   distributed under the terms of Sections 1 and 2 above on a medium
   customarily used for software interchange; or,
   
   @item
   Accompany it with the information you received as to the offer
   to distribute corresponding source code.  (This alternative is
   allowed only for noncommercial distribution and only if you
   received the program in object code or executable form with such
   an offer, in accord with Subsection b above.)
   @end enumerate
   
   The source code for a work means the preferred form of the work for
   making modifications to it.  For an executable work, complete source
   code means all the source code for all modules it contains, plus any
   associated interface definition files, plus the scripts used to
   control compilation and installation of the executable.  However, as a
   special exception, the source code distributed need not include
   anything that is normally distributed (in either source or binary
   form) with the major components (compiler, kernel, and so on) of the
   operating system on which the executable runs, unless that component
   itself accompanies the executable.
   
   If distribution of executable or object code is made by offering
   access to copy from a designated place, then offering equivalent
   access to copy the source code from the same place counts as
   distribution of the source code, even though third parties are not
   compelled to copy the source along with the object code.
   
   @item
   You may not copy, modify, sublicense, or distribute the Program
   except as expressly provided under this License.  Any attempt
   otherwise to copy, modify, sublicense or distribute the Program is
   void, and will automatically terminate your rights under this License.
   However, parties who have received copies, or rights, from you under
   this License will not have their licenses terminated so long as such
   parties remain in full compliance.
   
   @item
   You are not required to accept this License, since you have not
   signed it.  However, nothing else grants you permission to modify or
   distribute the Program or its derivative works.  These actions are
   prohibited by law if you do not accept this License.  Therefore, by
   modifying or distributing the Program (or any work based on the
   Program), you indicate your acceptance of this License to do so, and
   all its terms and conditions for copying, distributing or modifying
   the Program or works based on it.
   
   @item
   Each time you redistribute the Program (or any work based on the
   Program), the recipient automatically receives a license from the
   original licensor to copy, distribute or modify the Program subject to
   these terms and conditions.  You may not impose any further
   restrictions on the recipients' exercise of the rights granted herein.
   You are not responsible for enforcing compliance by third parties to
   this License.
   
   @item
   If, as a consequence of a court judgment or allegation of patent
   infringement or for any other reason (not limited to patent issues),
   conditions are imposed on you (whether by court order, agreement or
   otherwise) that contradict the conditions of this License, they do not
   excuse you from the conditions of this License.  If you cannot
   distribute so as to satisfy simultaneously your obligations under this
   License and any other pertinent obligations, then as a consequence you
   may not distribute the Program at all.  For example, if a patent
   license would not permit royalty-free redistribution of the Program by
   all those who receive copies directly or indirectly through you, then
   the only way you could satisfy both it and this License would be to
   refrain entirely from distribution of the Program.
   
   If any portion of this section is held invalid or unenforceable under
   any particular circumstance, the balance of the section is intended to
   apply and the section as a whole is intended to apply in other
   circumstances.
   
   It is not the purpose of this section to induce you to infringe any
   patents or other property right claims or to contest validity of any
   such claims; this section has the sole purpose of protecting the
   integrity of the free software distribution system, which is
   implemented by public license practices.  Many people have made
   generous contributions to the wide range of software distributed
   through that system in reliance on consistent application of that
   system; it is up to the author/donor to decide if he or she is willing
   to distribute software through any other system and a licensee cannot
   impose that choice.
   
   This section is intended to make thoroughly clear what is believed to
   be a consequence of the rest of this License.
   
   @item
   If the distribution and/or use of the Program is restricted in
   certain countries either by patents or by copyrighted interfaces, the
   original copyright holder who places the Program under this License
   may add an explicit geographical distribution limitation excluding
   those countries, so that distribution is permitted only in or among
   countries not thus excluded.  In such case, this License incorporates
   the limitation as if written in the body of this License.
   
   @item
   The Free Software Foundation may publish revised and/or new versions
   of the General Public 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.
   
   Each version is given a distinguishing version number.  If the Program
   specifies a version number of this License which applies to it and ``any
   later version'', you have the option of following the terms and conditions
   either of that version or of any later version published by the Free
   Software Foundation.  If the Program does not specify a version number of
   this License, you may choose any version ever published by the Free Software
   Foundation.
   
   @item
   If you wish to incorporate parts of the Program into other free
   programs whose distribution conditions are different, write to the author
   to ask for permission.  For software which is copyrighted by the Free
   Software Foundation, write to the Free Software Foundation; we sometimes
   make exceptions for this.  Our decision will be guided by the two goals
   of preserving the free status of all derivatives of our free software and
   of promoting the sharing and reuse of software generally.
   
   @iftex
   @heading NO WARRANTY
   @end iftex
   @ifinfo
   @center NO WARRANTY
   @end ifinfo
   
   @item
   BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
   FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
   OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
   PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
   OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
   TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
   PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
   REPAIR OR CORRECTION.
   
   @item
   IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
   WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
   REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
   INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
   OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
   TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
   YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
   PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
   POSSIBILITY OF SUCH DAMAGES.
   @end enumerate
   
   @iftex
   @heading END OF TERMS AND CONDITIONS
   @end iftex
   @ifinfo
   @center END OF TERMS AND CONDITIONS
   @end ifinfo
   
   @page
   @unnumberedsec How to Apply These Terms to Your New Programs
   
     If you develop a new program, and you want it to be of the greatest
   possible use to the public, the best way to achieve this is to make it
   free software which everyone can redistribute and change under these terms.
   
     To do so, attach the following notices to the program.  It is safest
   to attach them to the start of each source file to most effectively
   convey the exclusion of warranty; and each file should have at least
   the ``copyright'' line and a pointer to where the full notice is found.
   
   @smallexample
   @var{one line to give the program's name and a brief idea of what it does.}
   Copyright (C) 19@var{yy}  @var{name of author}
   
   This program is free software; you can redistribute it and/or modify 
   it under the terms of the GNU General Public License as published by 
   the 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 of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   @end smallexample
   
   Also add information on how to contact you by electronic and paper mail.
   
   If the program is interactive, make it output a short notice like this
   when it starts in an interactive mode:
   
   @smallexample
   Gnomovision version 69, Copyright (C) 19@var{yy} @var{name of author}
   Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
   type `show w'.  
   This is free software, and you are welcome to redistribute it 
   under certain conditions; type `show c' for details.
   @end smallexample
   
   The hypothetical commands @samp{show w} and @samp{show c} should show
   the appropriate parts of the General Public License.  Of course, the
   commands you use may be called something other than @samp{show w} and
   @samp{show c}; they could even be mouse-clicks or menu items---whatever
   suits your program.
   
   You should also get your employer (if you work as a programmer) or your
   school, if any, to sign a ``copyright disclaimer'' for the program, if
   necessary.  Here is a sample; alter the names:
   
   @smallexample
   Yoyodyne, Inc., hereby disclaims all copyright interest in the program
   `Gnomovision' (which makes passes at compilers) written by James Hacker.
   
   @var{signature of Ty Coon}, 1 April 1989
   Ty Coon, President of Vice
   @end smallexample
   
   This General Public License does not permit incorporating your program into
   proprietary programs.  If your program is a subroutine library, you may
   consider it more useful to permit linking proprietary applications with the
   library.  If this is what you want to do, use the GNU Library General
   Public License instead of this License.
   
 @iftex  @iftex
 @unnumbered Preface  @unnumbered Preface
Line 157  not written for ANS Forth, as you will n Line 545  not written for ANS Forth, as you will n
 deviations of the book.  deviations of the book.
   
 There is, of course, the standard, the definite reference if you want to  There is, of course, the standard, the definite reference if you want to
 write ANS Forth programs. It will be available in printed form from  write ANS Forth programs. It is available in printed form from the
 Global Engineering Documents !! somtime in spring or summer 1994. If you  National Standards Institute Sales Department (Tel.: USA (212) 642-4900;
 are lucky, you can still get dpANS6 (the draft that was approved as  Fax.: USA (212) 302-1286) as document @cite{X3.215-1994} for about $200. You
 standard) by aftp from ftp.uu.net:/vendor/minerva/x3j14.  can also get it from Global Engineering Documents (Tel.: USA (800)
   854-7179; Fax.: (303) 843-9880) for about $300.
   
   @cite{dpANS6}, the last draft of the standard, which was then submitted to ANSI
   for publication is available electronically and for free in some MS Word
   format, and it has been converted to HTML. Some pointers to these
   versions can be found through
   http://www.complang.tuwien.ac.at/projects/forth.html.
   
 @cite{Forth: The new model} by Jack Woehr (!! Publisher) is an  @cite{Forth: The new model} by Jack Woehr (Prentice-Hall, 1993) is an
 introductory book based on a draft version of the standard. It does not  introductory book based on a draft version of the standard. It does not
 cover the whole standard. It also contains interesting background  cover the whole standard. It also contains interesting background
 information (Jack Woehr was in the ANS Forth Technical Committe). It is  information (Jack Woehr was in the ANS Forth Technical Committe). It is
Line 193  line. They are: Line 588  line. They are:
   
 @table @code  @table @code
 @item --image-file @var{file}  @item --image-file @var{file}
   @item -i @var{file}
 Loads the Forth image @var{file} instead of the default  Loads the Forth image @var{file} instead of the default
 @file{gforth.fi}.  @file{gforth.fi}.
   
 @item --path @var{path}  @item --path @var{path}
   @item -p @var{path}
 Uses @var{path} for searching the image file and Forth source code  Uses @var{path} for searching the image file and Forth source code
 files instead of the default in the environment variable  files instead of the default in the environment variable
 @code{GFORTHPATH} or the path specified at installation time (typically  @code{GFORTHPATH} or the path specified at installation time (typically
Line 269  then in @file{~}, then in the normal pat Line 666  then in @file{~}, then in the normal pat
 * Blocks::                        * Blocks::                      
 * Other I/O::                     * Other I/O::                   
 * Programming Tools::             * Programming Tools::           
   * Assembler and Code words::    
 * Threading Words::               * Threading Words::             
 @end menu  @end menu
   
Line 300  effect}, but in @var{Description}. The n Line 698  effect}, but in @var{Description}. The n
 the type and/or the function of the item. See below for a discussion of  the type and/or the function of the item. See below for a discussion of
 the types.  the types.
   
   All words have two stack effects: A compile-time stack effect and a
   run-time stack effect. The compile-time stack-effect of most words is
   @var{ -- }. If the compile-time stack-effect of a word deviates from
   this standard behaviour, or the word does other unusual things at
   compile time, both stack effects are shown; otherwise only the run-time
   stack effect is shown.
   
 @item pronunciation  @item pronunciation
 How the word is pronounced  How the word is pronounced
   
Line 309  system need not support all of them. So, Line 714  system need not support all of them. So,
 uses the more portable it will be in theory. However, we suspect that  uses the more portable it will be in theory. However, we suspect that
 most ANS Forth systems on personal machines will feature all  most ANS Forth systems on personal machines will feature all
 wordsets. Words that are not defined in the ANS standard have  wordsets. Words that are not defined in the ANS standard have
 @code{gforth} as wordset.  @code{gforth} or @code{gforth-internal} as wordset. @code{gforth}
   describes words that will work in future releases of Gforth;
   @code{gforth-internal} words are more volatile. Environmental query
   strings are also displayed like words; you can recognize them by the
   @code{environment} in the wordset field.
   
 @item Description  @item Description
 A description of the behaviour of the word.  A description of the behaviour of the word.
Line 808  There are several variations on the coun Line 1217  There are several variations on the coun
   
 @code{LEAVE} leaves the innermost counted loop immediately.  @code{LEAVE} leaves the innermost counted loop immediately.
   
   If @var{start} is greater than @var{limit}, a @code{?DO} loop is entered
   (and @code{LOOP} iterates until they become equal by wrap-around
   arithmetic). This behaviour is usually not what you want. Therefore,
   Gforth offers @code{+DO} and @code{U+DO} (as replacements for
   @code{?DO}), which do not enter the loop if @var{start} is greater than
   @var{limit}; @code{+DO} is for signed loop parameters, @code{U+DO} for
   unsigned loop parameters. These words can be implemented easily on
   standard systems, so using them does not make your programs hard to
   port; e.g.:
   @example
   : +DO ( compile-time: -- do-sys; run-time: n1 n2 -- )
       POSTPONE over POSTPONE min POSTPONE ?DO ; immediate
   @end example
   
 @code{LOOP} can be replaced with @code{@var{n} +LOOP}; this updates the  @code{LOOP} can be replaced with @code{@var{n} +LOOP}; this updates the
 index by @var{n} instead of by 1. The loop is terminated when the border  index by @var{n} instead of by 1. The loop is terminated when the border
 between @var{limit-1} and @var{limit} is crossed. E.g.:  between @var{limit-1} and @var{limit} is crossed. E.g.:
   
 @code{4 0 ?DO  i .  2 +LOOP}   prints @code{0 2}  @code{4 0 +DO  i .  2 +LOOP}   prints @code{0 2}
   
 @code{4 1 ?DO  i .  2 +LOOP}   prints @code{1 3}  @code{4 1 +DO  i .  2 +LOOP}   prints @code{1 3}
   
 The behaviour of @code{@var{n} +LOOP} is peculiar when @var{n} is negative:  The behaviour of @code{@var{n} +LOOP} is peculiar when @var{n} is negative:
   
Line 822  The behaviour of @code{@var{n} +LOOP} is Line 1245  The behaviour of @code{@var{n} +LOOP} is
   
 @code{ 0 0 ?DO  i .  -1 +LOOP}  prints nothing  @code{ 0 0 ?DO  i .  -1 +LOOP}  prints nothing
   
 Therefore we recommend avoiding using @code{@var{n} +LOOP} with negative  Therefore we recommend avoiding @code{@var{n} +LOOP} with negative
 @var{n}. One alternative is @code{@var{n} S+LOOP}, where the negative  @var{n}. One alternative is @code{@var{u} -LOOP}, which reduces the
 case behaves symmetrical to the positive case:  index by @var{u} each iteration. The loop is terminated when the border
   between @var{limit+1} and @var{limit} is crossed. Gforth also provides
   @code{-DO} and @code{U-DO} for down-counting loops. E.g.:
   
   @code{-2 0 -DO  i .  1 -LOOP}  prints @code{0 -1}
   
 @code{-2 0 ?DO  i .  -1 S+LOOP}  prints @code{0 -1}  @code{-1 0 -DO  i .  1 -LOOP}  prints @code{0}
   
 @code{-1 0 ?DO  i .  -1 S+LOOP}  prints @code{0}  @code{ 0 0 -DO  i .  1 -LOOP}  prints nothing
   
 @code{ 0 0 ?DO  i .  -1 S+LOOP}  prints nothing  Another alternative is @code{@var{n} S+LOOP}, where the negative
   case behaves symmetrical to the positive case:
   
 The loop is terminated when the border between @var{limit@minus{}sgn(n)} and  @code{-2 0 -DO  i .  -1 S+LOOP}  prints @code{0 -1}
 @var{limit} is crossed. However, @code{S+LOOP} is not part of the ANS  
 Forth standard.  
   
 @code{?DO} can be replaced by @code{DO}. @code{DO} enters the loop even  The loop is terminated when the border between @var{limit@minus{}sgn(n)}
 when the start and the limit value are equal. We do not recommend using  and @var{limit} is crossed. Unfortunately, neither @code{-LOOP} nor
 @code{DO}. It will just give you maintenance troubles.  @code{S+LOOP} are part of the ANS Forth standard, and they are not easy
   to implement using standard words. If you want to write standard
   programs, just avoid counting down.
   
   @code{?DO} can also be replaced by @code{DO}. @code{DO} always enters
   the loop, independent of the loop parameters. Do not use @code{DO}, even
   if you know that the loop is entered in any case. Such knowledge tends
   to become invalid during maintenance of a program, and then the
   @code{DO} will make trouble.
   
 @code{UNLOOP} is used to prepare for an abnormal loop exit, e.g., via  @code{UNLOOP} is used to prepare for an abnormal loop exit, e.g., via
 @code{EXIT}. @code{UNLOOP} removes the loop control parameters from the  @code{EXIT}. @code{UNLOOP} removes the loop control parameters from the
Line 894  doc-repeat Line 1328  doc-repeat
 Counted loop words constitute a separate group of words:  Counted loop words constitute a separate group of words:
   
 doc-?do  doc-?do
   doc-+do
   doc-u+do
   doc--do
   doc-u-do
 doc-do  doc-do
 doc-for  doc-for
 doc-loop  doc-loop
 doc-s+loop  doc-s+loop
 doc-+loop  doc-+loop
   doc--loop
 doc-next  doc-next
 doc-leave  doc-leave
 doc-?leave  doc-?leave
Line 1526  locals wordset. Line 1965  locals wordset.
 @node Other I/O, Programming Tools, Blocks, Words  @node Other I/O, Programming Tools, Blocks, Words
 @section Other I/O  @section Other I/O
   
 @node Programming Tools, Threading Words, Other I/O, Words  @node Programming Tools, Assembler and Code words, Other I/O, Words
 @section Programming Tools  @section Programming Tools
   
 @menu  @menu
Line 1625  If there is interest, we will introduce Line 2064  If there is interest, we will introduce
 intend to @code{catch} a specific condition, using @code{throw} is  intend to @code{catch} a specific condition, using @code{throw} is
 probably more appropriate than an assertion).  probably more appropriate than an assertion).
   
 @node Threading Words,  , Programming Tools, Words  @node Assembler and Code words, Threading Words, Programming Tools, Words
   @section Assembler and Code words
   
   Gforth provides some words for defining primitives (words written in
   machine code), and for defining the the machine-code equivalent of
   @code{DOES>}-based defining words. However, the machine-independent
   nature of Gforth poses a few problems: First of all. Gforth runs on
   several architectures, so it can provide no standard assembler. What's
   worse is that the register allocation not only depends on the processor,
   but also on the gcc version and options used.
   
   The words Gforth offers encapsulate some system dependences (e.g., the
   header structure), so a system-independent assembler may be used in
   Gforth. If you do not have an assembler, you can compile machine code
   directly with @code{,} and @code{c,}.
   
   doc-assembler
   doc-code
   doc-end-code
   doc-;code
   doc-flush-icache
   
   If @code{flush-icache} does not work correctly, @code{code} words
   etc. will not work (reliably), either.
   
   These words are rarely used. Therefore they reside in @code{code.fs},
   which is usually not loaded (except @code{flush-icache}, which is always
   present). You can load them with @code{require code.fs}.
   
   Another option for implementing normal and defining words efficiently
   is: adding the wanted functionality to the source of Gforth. For normal
   words you just have to edit @file{primitives}, defining words (for fast
   defined words) probably require changes in @file{engine.c},
   @file{kernal.fs}, @file{prims2x.fs}, and possibly @file{cross.fs}.
   
   
   @node Threading Words,  , Assembler and Code words, Words
 @section Threading Words  @section Threading Words
   
 These words provide access to code addresses and other threading stuff  These words provide access to code addresses and other threading stuff
Line 1643  doc-does-code! Line 2118  doc-does-code!
 doc-does-handler!  doc-does-handler!
 doc-/does-handler  doc-/does-handler
   
   The code addresses produced by various defining words are produced by
   the following words:
   
   doc-docol:
   doc-docon:
   doc-dovar:
   doc-douser:
   doc-dodefer:
   doc-dofield:
   
   Currently there is no installation-independent way for recogizing words
   defined by a @code{CREATE}...@code{DOES>} word; however, once you know
   that a word is defined by a @code{CREATE}...@code{DOES>} word, you can
   use @code{>DOES-CODE}.
   
 @node ANS conformance, Model, Words, Top  @node ANS conformance, Model, Words, Top
 @chapter ANS conformance  @chapter ANS conformance
Line 1670  ANS Forth System Line 2158  ANS Forth System
 @item providing the Memory-Allocation word set  @item providing the Memory-Allocation word set
 @item providing the Memory-Allocation Extensions word set (that one's easy)  @item providing the Memory-Allocation Extensions word set (that one's easy)
 @item providing the Programming-Tools word set  @item providing the Programming-Tools word set
 @item providing @code{AHEAD}, @code{BYE}, @code{CS-PICK}, @code{CS-ROLL}, @code{STATE}, @code{[ELSE]}, @code{[IF]}, @code{[THEN]} from the Programming-Tools Extensions word set  @item providing @code{;code}, @code{AHEAD}, @code{ASSEMBLER}, @code{BYE}, @code{CODE}, @code{CS-PICK}, @code{CS-ROLL}, @code{STATE}, @code{[ELSE]}, @code{[IF]}, @code{[THEN]} from the Programming-Tools Extensions word set
 @item providing the Search-Order word set  @item providing the Search-Order word set
 @item providing the Search-Order Extensions word set  @item providing the Search-Order Extensions word set
 @item providing the String word set  @item providing the String word set
Line 1993  Compiles a recursive call to the definin Line 2481  Compiles a recursive call to the definin
   
 @item argument input source different than current input source for @code{RESTORE-INPUT}:  @item argument input source different than current input source for @code{RESTORE-INPUT}:
 !!???If the argument input source is a valid input source then it gets  !!???If the argument input source is a valid input source then it gets
 restored. Otherwise causes @code{-12 THROW} which unless caught issues  restored. Otherwise causes @code{-12 THROW}, which, unless caught, issues
 the message "argument type mismatch" and aborts.  the message "argument type mismatch" and aborts.
   
 @item data space containing definitions gets de-allocated:  @item data space containing definitions gets de-allocated:
Line 3100  Sieve benchmark on a 486DX2/66 than Gfor Line 3588  Sieve benchmark on a 486DX2/66 than Gfor
 However, this potential advantage of assembly language implementations  However, this potential advantage of assembly language implementations
 is not necessarily realized in complete Forth systems: We compared  is not necessarily realized in complete Forth systems: We compared
 Gforth (compiled with @code{gcc-2.6.3} and @code{-DFORCE_REG}) with  Gforth (compiled with @code{gcc-2.6.3} and @code{-DFORCE_REG}) with
 Win32Forth and LMI's NT Forth, two systems written in assembly, and with  Win32Forth 1.2093 and LMI's NT Forth (Beta, May 1994), two systems
 two systems written in C: PFE-0.9.11 (compiled with @code{gcc-2.6.3}  written in assembly, and with two systems written in C: PFE-0.9.11
 with the default configuration for Linux: @code{-O2 -fomit-frame-pointer  (compiled with @code{gcc-2.6.3} with the default configuration for
 -DUSE_REGS}) and ThisForth Beta (compiled with gcc-2.6.3 -O3  Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS}) and ThisForth Beta
 -fomit-frame-pointer). We benchmarked Gforth, PFE and ThisForth on a  (compiled with gcc-2.6.3 -O3 -fomit-frame-pointer). We benchmarked
 486DX2/66 under Linux. Kenneth O'Heskin kindly provided the results for  Gforth, PFE and ThisForth on a 486DX2/66 under Linux. Kenneth O'Heskin
 Win32Forth and NT Forth on a 486DX2/66 with similar memory performance  kindly provided the results for Win32Forth and NT Forth on a 486DX2/66
 under Windows NT.  with similar memory performance under Windows NT.
     
 We used four small benchmarks: the ubiquitous Sieve; bubble-sorting and  We used four small benchmarks: the ubiquitous Sieve; bubble-sorting and
 matrix multiplication come from the Stanford integer benchmarks and have  matrix multiplication come from the Stanford integer benchmarks and have
Line 3197  information about Forth there. Line 3685  information about Forth there.
 @node Word Index, Node Index, Pedigree, Top  @node Word Index, Node Index, Pedigree, Top
 @chapter Word Index  @chapter Word Index
   
 This index is as incomplete as the manual.  This index is as incomplete as the manual. Each word is listed with
   stack effect and wordset.
   
 @printindex fn  @printindex fn
   
Removed from v.1.17  
changed lines
  Added in v.1.21

FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>