version 1.17, 1995/09/15 14:52:51
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version 1.34, 1996/08/21 14:58:40
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@comment %**end of header (This is for running Texinfo on a region.) |
@comment %**end of header (This is for running Texinfo on a region.) |
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@ifinfo |
@ifinfo |
This file documents Gforth 0.1 |
This file documents Gforth 0.2 |
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Copyright @copyright{} 1994 Gforth Development Group |
Copyright @copyright{} 1995,1996 Free Software Foundation, Inc. |
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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 36 Copyright @copyright{} 1994 Gforth Devel
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Line 36 Copyright @copyright{} 1994 Gforth Devel
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of in the original English. |
of in the original English. |
@end ifinfo |
@end ifinfo |
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@finalout |
@titlepage |
@titlepage |
@sp 10 |
@sp 10 |
@center @titlefont{Gforth Manual} |
@center @titlefont{Gforth Manual} |
@sp 2 |
@sp 2 |
@center for version 0.1 |
@center for version 0.2 |
@sp 2 |
@sp 2 |
@center Anton Ertl |
@center Anton Ertl |
|
@center Bernd Paysan |
@sp 3 |
@sp 3 |
@center This manual is under construction |
@center This manual is under construction |
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@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{} 1995,1996 Free Software Foundation, Inc. |
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@comment !! Published by ... or You can get a copy of this manual ... |
@comment !! Published by ... or You can get a copy of this manual ... |
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Line 75 Copyright @copyright{} 1994 Gforth Devel
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Line 77 Copyright @copyright{} 1994 Gforth Devel
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@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 0.2. |
@end ifinfo |
@end ifinfo |
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@menu |
@menu |
Line 86 personal machines. This manual correspon
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Line 88 personal machines. This manual correspon
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* Words:: Forth words available in Gforth |
* Words:: Forth words available in Gforth |
* ANS conformance:: Implementation-defined options etc. |
* ANS conformance:: Implementation-defined options etc. |
* Model:: The abstract machine of Gforth |
* Model:: The abstract machine of Gforth |
|
* Integrating Gforth:: Forth as scripting language for applications. |
* Emacs and Gforth:: The Gforth Mode |
* Emacs and Gforth:: The Gforth Mode |
* Internals:: Implementation details |
* Internals:: Implementation details |
* Bugs:: How to report them |
* Bugs:: How to report them |
* Pedigree:: Ancestors of Gforth |
* Origin:: Authors and ancestors of Gforth |
* Word Index:: An item for each Forth word |
* Word Index:: An item for each Forth word |
* Node Index:: An item for each node |
* Node Index:: An item for each node |
@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 |
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@display |
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Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc. |
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675 Mass Ave, Cambridge, MA 02139, USA |
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Everyone is permitted to copy and distribute verbatim copies |
|
of this license document, but changing it is not allowed. |
|
@end display |
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|
|
@unnumberedsec Preamble |
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|
|
The licenses for most software are designed to take away your |
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freedom to share and change it. By contrast, the GNU General Public |
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License is intended to guarantee your freedom to share and change free |
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software---to make sure the software is free for all its users. This |
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General Public License applies to most of the Free Software |
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Foundation's software and to any other program whose authors commit to |
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using it. (Some other Free Software Foundation software is covered by |
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the GNU Library General Public License instead.) You can apply it to |
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your programs, too. |
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When we speak of free software, we are referring to freedom, not |
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price. Our General Public Licenses are designed to make sure that you |
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have the freedom to distribute copies of free software (and charge for |
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this service if you wish), that you receive source code or can get it |
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if you want it, that you can change the software or use pieces of it |
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in new free programs; and that you know you can do these things. |
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To protect your rights, we need to make restrictions that forbid |
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anyone to deny you these rights or to ask you to surrender the rights. |
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These restrictions translate to certain responsibilities for you if you |
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distribute copies of the software, or if you modify it. |
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For example, if you distribute copies of such a program, whether |
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gratis or for a fee, you must give the recipients all the rights that |
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you have. You must make sure that they, too, receive or can get the |
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source code. And you must show them these terms so they know their |
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rights. |
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We protect your rights with two steps: (1) copyright the software, and |
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(2) offer you this license which gives you legal permission to copy, |
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distribute and/or modify the software. |
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Also, for each author's protection and ours, we want to make certain |
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that everyone understands that there is no warranty for this free |
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software. If the software is modified by someone else and passed on, we |
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want its recipients to know that what they have is not the original, so |
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that any problems introduced by others will not reflect on the original |
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authors' reputations. |
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Finally, any free program is threatened constantly by software |
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patents. We wish to avoid the danger that redistributors of a free |
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program will individually obtain patent licenses, in effect making the |
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program proprietary. To prevent this, we have made it clear that any |
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patent must be licensed for everyone's free use or not licensed at all. |
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The precise terms and conditions for copying, distribution and |
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modification follow. |
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@iftex |
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@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION |
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@end iftex |
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@ifinfo |
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@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION |
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@end ifinfo |
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@enumerate 0 |
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@item |
|
This License applies to any program or other work which contains |
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a notice placed by the copyright holder saying it may be distributed |
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under the terms of this General Public License. The ``Program'', below, |
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refers to any such program or work, and a ``work based on the Program'' |
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means either the Program or any derivative work under copyright law: |
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that is to say, a work containing the Program or a portion of it, |
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either verbatim or with modifications and/or translated into another |
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language. (Hereinafter, translation is included without limitation in |
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the term ``modification''.) Each licensee is addressed as ``you''. |
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Activities other than copying, distribution and modification are not |
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covered by this License; they are outside its scope. The act of |
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running the Program is not restricted, and the output from the Program |
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is covered only if its contents constitute a work based on the |
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Program (independent of having been made by running the Program). |
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Whether that is true depends on what the Program does. |
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@item |
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You may copy and distribute verbatim copies of the Program's |
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source code as you receive it, in any medium, provided that you |
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conspicuously and appropriately publish on each copy an appropriate |
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copyright notice and disclaimer of warranty; keep intact all the |
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notices that refer to this License and to the absence of any warranty; |
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and give any other recipients of the Program a copy of this License |
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along with the Program. |
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You may charge a fee for the physical act of transferring a copy, and |
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you may at your option offer warranty protection in exchange for a fee. |
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@item |
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You may modify your copy or copies of the Program or any portion |
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of it, thus forming a work based on the Program, and copy and |
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distribute such modifications or work under the terms of Section 1 |
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above, provided that you also meet all of these conditions: |
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|
@enumerate a |
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@item |
|
You must cause the modified files to carry prominent notices |
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stating that you changed the files and the date of any change. |
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@item |
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You must cause any work that you distribute or publish, that in |
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whole or in part contains or is derived from the Program or any |
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part thereof, to be licensed as a whole at no charge to all third |
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parties under the terms of this License. |
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@item |
|
If the modified program normally reads commands interactively |
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when run, you must cause it, when started running for such |
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interactive use in the most ordinary way, to print or display an |
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announcement including an appropriate copyright notice and a |
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notice that there is no warranty (or else, saying that you provide |
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a warranty) and that users may redistribute the program under |
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these conditions, and telling the user how to view a copy of this |
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License. (Exception: if the Program itself is interactive but |
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does not normally print such an announcement, your work based on |
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the Program is not required to print an announcement.) |
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@end enumerate |
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These requirements apply to the modified work as a whole. If |
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identifiable sections of that work are not derived from the Program, |
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and can be reasonably considered independent and separate works in |
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themselves, then this License, and its terms, do not apply to those |
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sections when you distribute them as separate works. But when you |
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distribute the same sections as part of a whole which is a work based |
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on the Program, the distribution of the whole must be on the terms of |
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this License, whose permissions for other licensees extend to the |
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entire whole, and thus to each and every part regardless of who wrote it. |
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Thus, it is not the intent of this section to claim rights or contest |
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your rights to work written entirely by you; rather, the intent is to |
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exercise the right to control the distribution of derivative or |
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collective works based on the Program. |
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In addition, mere aggregation of another work not based on the Program |
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with the Program (or with a work based on the Program) on a volume of |
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a storage or distribution medium does not bring the other work under |
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the scope of this License. |
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@item |
|
You may copy and distribute the Program (or a work based on it, |
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under Section 2) in object code or executable form under the terms of |
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Sections 1 and 2 above provided that you also do one of the following: |
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|
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@enumerate a |
|
@item |
|
Accompany it with the complete corresponding machine-readable |
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source code, which must be distributed under the terms of Sections |
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1 and 2 above on a medium customarily used for software interchange; or, |
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@item |
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Accompany it with a written offer, valid for at least three |
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years, to give any third party, for a charge no more than your |
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cost of physically performing source distribution, a complete |
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machine-readable copy of the corresponding source code, to be |
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distributed under the terms of Sections 1 and 2 above on a medium |
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customarily used for software interchange; or, |
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|
|
@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 |
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received the program in object code or executable form with such |
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an offer, in accord with Subsection b above.) |
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@end enumerate |
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|
|
The source code for a work means the preferred form of the work for |
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making modifications to it. For an executable work, complete source |
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code means all the source code for all modules it contains, plus any |
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associated interface definition files, plus the scripts used to |
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control compilation and installation of the executable. However, as a |
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special exception, the source code distributed need not include |
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anything that is normally distributed (in either source or binary |
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form) with the major components (compiler, kernel, and so on) of the |
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operating system on which the executable runs, unless that component |
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itself accompanies the executable. |
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If distribution of executable or object code is made by offering |
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access to copy from a designated place, then offering equivalent |
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access to copy the source code from the same place counts as |
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distribution of the source code, even though third parties are not |
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compelled to copy the source along with the object code. |
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@item |
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You may not copy, modify, sublicense, or distribute the Program |
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except as expressly provided under this License. Any attempt |
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otherwise to copy, modify, sublicense or distribute the Program is |
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void, and will automatically terminate your rights under this License. |
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However, parties who have received copies, or rights, from you under |
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this License will not have their licenses terminated so long as such |
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parties remain in full compliance. |
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@item |
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You are not required to accept this License, since you have not |
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signed it. However, nothing else grants you permission to modify or |
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distribute the Program or its derivative works. These actions are |
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prohibited by law if you do not accept this License. Therefore, by |
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modifying or distributing the Program (or any work based on the |
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Program), you indicate your acceptance of this License to do so, and |
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all its terms and conditions for copying, distributing or modifying |
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the Program or works based on it. |
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@item |
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Each time you redistribute the Program (or any work based on the |
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Program), the recipient automatically receives a license from the |
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original licensor to copy, distribute or modify the Program subject to |
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these terms and conditions. You may not impose any further |
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restrictions on the recipients' exercise of the rights granted herein. |
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You are not responsible for enforcing compliance by third parties to |
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this License. |
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@item |
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If, as a consequence of a court judgment or allegation of patent |
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infringement or for any other reason (not limited to patent issues), |
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conditions are imposed on you (whether by court order, agreement or |
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otherwise) that contradict the conditions of this License, they do not |
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excuse you from the conditions of this License. If you cannot |
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distribute so as to satisfy simultaneously your obligations under this |
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License and any other pertinent obligations, then as a consequence you |
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may not distribute the Program at all. For example, if a patent |
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license would not permit royalty-free redistribution of the Program by |
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all those who receive copies directly or indirectly through you, then |
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the only way you could satisfy both it and this License would be to |
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refrain entirely from distribution of the Program. |
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|
If any portion of this section is held invalid or unenforceable under |
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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. |
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|
|
It is not the purpose of this section to induce you to infringe any |
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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 |
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generous contributions to the wide range of software distributed |
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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 |
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to distribute software through any other system and a licensee cannot |
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impose that choice. |
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|
|
This section is intended to make thoroughly clear what is believed to |
|
be a consequence of the rest of this License. |
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|
|
@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 |
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those countries, so that distribution is permitted only in or among |
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countries not thus excluded. In such case, this License incorporates |
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the limitation as if written in the body of this License. |
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|
@item |
|
The Free Software Foundation may publish revised and/or new versions |
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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. |
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|
Each version is given a distinguishing version number. If the Program |
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specifies a version number of this License which applies to it and ``any |
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later version'', you have the option of following the terms and conditions |
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either of that version or of any later version published by the Free |
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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 |
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Foundation. |
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|
|
@item |
|
If you wish to incorporate parts of the Program into other free |
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programs whose distribution conditions are different, write to the author |
|
to ask for permission. For software which is copyrighted by the Free |
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Software Foundation, write to the Free Software Foundation; we sometimes |
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make exceptions for this. Our decision will be guided by the two goals |
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of preserving the free status of all derivatives of our free software and |
|
of promoting the sharing and reuse of software generally. |
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|
|
@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 |
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS |
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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 |
@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 |
|
@node Preface |
|
@comment node-name, next, previous, up |
@unnumbered Preface |
@unnumbered Preface |
|
@cindex Preface |
This manual documents Gforth. The reader is expected to know |
This manual documents Gforth. The reader is expected to know |
Forth. This manual is primarily a reference manual. @xref{Other Books} |
Forth. This manual is primarily a reference manual. @xref{Other Books} |
for introductory material. |
for introductory material. |
Line 157 not written for ANS Forth, as you will n
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Line 551 not written for ANS Forth, as you will n
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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 |
|
@*@file{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 594 line. They are:
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|
|
@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 245 Forth words, you have to quote them or u
|
Line 648 Forth words, you have to quote them or u
|
after processing the command line (instead of entering interactive mode) |
after processing the command line (instead of entering interactive mode) |
append @code{-e bye} to the command line. |
append @code{-e bye} to the command line. |
|
|
|
If you have several versions of Gforth installed, @code{gforth} will |
|
invoke the version that was installed last. @code{gforth-@var{version}} |
|
invokes a specific version. You may want to use the option |
|
@code{--path}, if your environment contains the variable |
|
@code{GFORTHPATH}. |
|
|
Not yet implemented: |
Not yet implemented: |
On startup the system first executes the system initialization file |
On startup the system first executes the system initialization file |
(unless the option @code{--no-init-file} is given; note that the system |
(unless the option @code{--no-init-file} is given; note that the system |
Line 269 then in @file{~}, then in the normal pat
|
Line 678 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 710 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 726 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 721 system that only supplies @code{THEN} is
|
Line 1142 system that only supplies @code{THEN} is
|
Forth's @code{THEN} has the meaning 2b, whereas @code{THEN} in Pascal |
Forth's @code{THEN} has the meaning 2b, whereas @code{THEN} in Pascal |
and many other programming languages has the meaning 3d.] |
and many other programming languages has the meaning 3d.] |
|
|
We also provide the words @code{?dup-if} and @code{?dup-0=-if}, so you |
Gforth also provides the words @code{?dup-if} and @code{?dup-0=-if}, so |
can avoid using @code{?dup}. |
you can avoid using @code{?dup}. Using these alternatives is also more |
|
efficient than using @code{?dup}. Definitions in plain standard Forth |
|
for @code{ENDIF}, @code{?DUP-IF} and @code{?DUP-0=-IF} are provided in |
|
@file{compat/control.fs}. |
|
|
@example |
@example |
@var{n} |
@var{n} |
Line 808 There are several variations on the coun
|
Line 1232 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. |
|
|
@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 1254 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{-2 0 ?DO i . -1 S+LOOP} prints @code{0 -1} |
@code{-DO} and @code{U-DO} for down-counting loops. E.g.: |
|
|
@code{-1 0 ?DO i . -1 S+LOOP} prints @code{0} |
@code{-2 0 -DO i . 1 -LOOP} prints @code{0 -1} |
|
|
@code{ 0 0 ?DO i . -1 S+LOOP} prints nothing |
@code{-1 0 -DO i . 1 -LOOP} prints @code{0} |
|
|
The loop is terminated when the border between @var{limit@minus{}sgn(n)} and |
@code{ 0 0 -DO i . 1 -LOOP} prints nothing |
@var{limit} is crossed. However, @code{S+LOOP} is not part of the ANS |
|
Forth standard. |
Unfortunately, @code{+DO}, @code{U+DO}, @code{-DO}, @code{U-DO} and |
|
@code{-LOOP} are not in the ANS Forth standard. However, an |
@code{?DO} can be replaced by @code{DO}. @code{DO} enters the loop even |
implementation for these words that uses only standard words is provided |
when the start and the limit value are equal. We do not recommend using |
in @file{compat/loops.fs}. |
@code{DO}. It will just give you maintenance troubles. |
|
|
@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 855 This is the preferred loop of native cod
|
Line 1292 This is the preferred loop of native cod
|
lazy to optimize @code{?DO} loops properly. In Gforth, this loop |
lazy to optimize @code{?DO} loops properly. In Gforth, this loop |
iterates @var{n+1} times; @code{i} produces values starting with @var{n} |
iterates @var{n+1} times; @code{i} produces values starting with @var{n} |
and ending with 0. Other Forth systems may behave differently, even if |
and ending with 0. Other Forth systems may behave differently, even if |
they support @code{FOR} loops. |
they support @code{FOR} loops. To avoid problems, don't use @code{FOR} |
|
loops. |
|
|
@node Arbitrary control structures, Calls and returns, Counted Loops, Control Structures |
@node Arbitrary control structures, Calls and returns, Counted Loops, Control Structures |
@subsection Arbitrary control structures |
@subsection Arbitrary control structures |
Line 891 doc-else
|
Line 1329 doc-else
|
doc-while |
doc-while |
doc-repeat |
doc-repeat |
|
|
|
Gforth adds some more control-structure words: |
|
|
|
doc-endif |
|
doc-?dup-if |
|
doc-?dup-0=-if |
|
|
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-+loop |
doc-+loop |
|
doc--loop |
doc-next |
doc-next |
doc-leave |
doc-leave |
doc-?leave |
doc-?leave |
Line 961 while
|
Line 1409 while
|
repeat |
repeat |
@end example |
@end example |
|
|
That's much easier to read, isn't it? Of course, @code{BEGIN} and |
That's much easier to read, isn't it? Of course, @code{REPEAT} and |
@code{WHILE} are predefined, so in this example it would not be |
@code{WHILE} are predefined, so in this example it would not be |
necessary to define them. |
necessary to define them. |
|
|
Line 995 laden with restrictions. Therefore, we p
|
Line 1443 laden with restrictions. Therefore, we p
|
locals wordset, but also our own, more powerful locals wordset (we |
locals wordset, but also our own, more powerful locals wordset (we |
implemented the ANS Forth locals wordset through our locals wordset). |
implemented the ANS Forth locals wordset through our locals wordset). |
|
|
|
The ideas in this section have also been published in the paper |
|
@cite{Automatic Scoping of Local Variables} by M. Anton Ertl, presented |
|
at EuroForth '94; it is available at |
|
@*@file{http://www.complang.tuwien.ac.at/papers/ertl94l.ps.gz}. |
|
|
@menu |
@menu |
* Gforth locals:: |
* Gforth locals:: |
* ANS Forth locals:: |
* ANS Forth locals:: |
Line 1281 E.g., a definition using @code{TO} might
|
Line 1734 E.g., a definition using @code{TO} might
|
: strcmp @{ addr1 u1 addr2 u2 -- n @} |
: strcmp @{ addr1 u1 addr2 u2 -- n @} |
u1 u2 min 0 |
u1 u2 min 0 |
?do |
?do |
addr1 c@ addr2 c@ - ?dup |
addr1 c@ addr2 c@ - |
if |
?dup-if |
unloop exit |
unloop exit |
then |
then |
addr1 char+ TO addr1 |
addr1 char+ TO addr1 |
Line 1304 are initialized with the right value for
|
Line 1757 are initialized with the right value for
|
addr1 addr2 |
addr1 addr2 |
u1 u2 min 0 |
u1 u2 min 0 |
?do @{ s1 s2 @} |
?do @{ s1 s2 @} |
s1 c@ s2 c@ - ?dup |
s1 c@ s2 c@ - |
if |
?dup-if |
unloop exit |
unloop exit |
then |
then |
s1 char+ s2 char+ |
s1 char+ s2 char+ |
Line 1484 name produces their value. Their value c
|
Line 1937 name produces their value. Their value c
|
|
|
Since this syntax is supported by Gforth directly, you need not do |
Since this syntax is supported by Gforth directly, you need not do |
anything to use it. If you want to port a program using this syntax to |
anything to use it. If you want to port a program using this syntax to |
another ANS Forth system, use @file{anslocal.fs} to implement the syntax |
another ANS Forth system, use @file{compat/anslocal.fs} to implement the |
on the other system. |
syntax on the other system. |
|
|
Note that a syntax shown in the standard, section A.13 looks |
Note that a syntax shown in the standard, section A.13 looks |
similar, but is quite different in having the order of locals |
similar, but is quite different in having the order of locals |
Line 1526 locals wordset.
|
Line 1979 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 2078 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 @code{gcc} version and options used. |
|
|
|
The words that 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}. |
|
|
|
In the assembly code you will want to refer to the inner interpreter's |
|
registers (e.g., the data stack pointer) and you may want to use other |
|
registers for temporary storage. Unfortunately, the register allocation |
|
is installation-dependent. |
|
|
|
The easiest solution is to use explicit register declarations |
|
(@pxref{Explicit Reg Vars, , Variables in Specified Registers, gcc.info, |
|
GNU C Manual}) for all of the inner interpreter's registers: You have to |
|
compile Gforth with @code{-DFORCE_REG} (configure option |
|
@code{--enable-force-reg}) and the appropriate declarations must be |
|
present in the @code{machine.h} file (see @code{mips.h} for an example; |
|
you can find a full list of all declarable register symbols with |
|
@code{grep register engine.c}). If you give explicit registers to all |
|
variables that are declared at the beginning of @code{engine()}, you |
|
should be able to use the other caller-saved registers for temporary |
|
storage. Alternatively, you can use the @code{gcc} option |
|
@code{-ffixed-REG} (@pxref{Code Gen Options, , Options for Code |
|
Generation Conventions, gcc.info, GNU C Manual}) to reserve a register |
|
(however, this restriction on register allocation may slow Gforth |
|
significantly). |
|
|
|
If this solution is not viable (e.g., because @code{gcc} does not allow |
|
you to explicitly declare all the registers you need), you have to find |
|
out by looking at the code where the inner interpreter's registers |
|
reside and which registers can be used for temporary storage. You can |
|
get an assembly listing of the engine's code with @code{make engine.s}. |
|
|
|
In any case, it is good practice to abstract your assembly code from the |
|
actual register allocation. E.g., if the data stack pointer resides in |
|
register @code{$17}, create an alias for this register called @code{sp}, |
|
and use that in your assembly code. |
|
|
|
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) may 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 2164 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 1651 doc-/does-handler
|
Line 2185 doc-/does-handler
|
To the best of our knowledge, Gforth is an |
To the best of our knowledge, Gforth is an |
|
|
ANS Forth System |
ANS Forth System |
@itemize |
@itemize @bullet |
@item providing the Core Extensions word set |
@item providing the Core Extensions word set |
@item providing the Block word set |
@item providing the Block word set |
@item providing the Block Extensions word set |
@item providing the Block Extensions word set |
Line 1670 ANS Forth System
|
Line 2204 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 1881 characters is determined by the locale y
|
Line 2415 characters is determined by the locale y
|
|
|
@item division rounding: |
@item division rounding: |
installation dependent. @code{s" floored" environment? drop .}. We leave |
installation dependent. @code{s" floored" environment? drop .}. We leave |
the choice to gcc (what to use for @code{/}) and to you (whether to use |
the choice to @code{gcc} (what to use for @code{/}) and to you (whether to use |
@code{fm/mod}, @code{sm/rem} or simply @code{/}). |
@code{fm/mod}, @code{sm/rem} or simply @code{/}). |
|
|
@item values of @code{STATE} when true: |
@item values of @code{STATE} when true: |
Line 1992 The next invocation of a parsing word re
|
Line 2526 The next invocation of a parsing word re
|
Compiles a recursive call to the defining word not to the defined word. |
Compiles a recursive call to the defining word not to the defined word. |
|
|
@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 |
@code{-12 THROW}. Note that, once an input file is closed (e.g., because |
restored. Otherwise causes @code{-12 THROW} which unless caught issues |
the end of the file was reached), its source-id may be |
the message "argument type mismatch" and aborts. |
reused. Therefore, restoring an input source specification referencing a |
|
closed file may lead to unpredictable results instead of a @code{-12 |
|
THROW}. |
|
|
|
In the future, Gforth may be able to retore input source specifications |
|
from other than the current input soruce. |
|
|
@item data space containing definitions gets de-allocated: |
@item data space containing definitions gets de-allocated: |
Deallocation with @code{allot} is not checked. This typically resuls in |
Deallocation with @code{allot} is not checked. This typically resuls in |
Line 2066 Not checked. As usual, you can expect me
|
Line 2605 Not checked. As usual, you can expect me
|
None. |
None. |
|
|
@item operator's terminal facilities available: |
@item operator's terminal facilities available: |
!!?? |
After processing the command line, Gforth goes into interactive mode, |
|
and you can give commands to Gforth interactively. The actual facilities |
|
available depend on how you invoke Gforth. |
|
|
@item program data space available: |
@item program data space available: |
@code{sp@ here - .} gives the space remaining for dictionary and data |
@code{sp@ here - .} gives the space remaining for dictionary and data |
stack together. |
stack together. |
|
|
@item return stack space available: |
@item return stack space available: |
!!?? |
By default 16 KBytes. The default can be overridden with the @code{-r} |
|
switch (@pxref{Invocation}) when Gforth starts up. |
|
|
@item stack space available: |
@item stack space available: |
@code{sp@ here - .} gives the space remaining for dictionary and data |
@code{sp@ here - .} gives the space remaining for dictionary and data |
Line 2394 System dependent; @code{REPRESENT} is im
|
Line 2936 System dependent; @code{REPRESENT} is im
|
function @code{ecvt()} and inherits its behaviour in this respect. |
function @code{ecvt()} and inherits its behaviour in this respect. |
|
|
@item rounding or truncation of floating-point numbers: |
@item rounding or truncation of floating-point numbers: |
What's the question?!! |
System dependent; the rounding behaviour is inherited from the hosting C |
|
compiler. IEEE-FP-based (i.e., most) systems by default round to |
|
nearest, and break ties by rounding to even (i.e., such that the last |
|
bit of the mantissa is 0). |
|
|
@item size of floating-point stack: |
@item size of floating-point stack: |
@code{s" FLOATING-STACK" environment? drop .}. Can be changed at startup |
@code{s" FLOATING-STACK" environment? drop .}. Can be changed at startup |
Line 2654 Not implemented (yet).
|
Line 3199 Not implemented (yet).
|
@table @i |
@table @i |
|
|
@item changing the compilation wordlist (during compilation): |
@item changing the compilation wordlist (during compilation): |
The definition is put into the wordlist that is the compilation wordlist |
The word is entered into the wordlist that was the compilation wordlist |
when @code{REVEAL} is executed (by @code{;}, @code{DOES>}, |
at the start of the definition. Any changes to the name field (e.g., |
@code{RECURSIVE}, etc.). |
@code{immediate}) or the code field (e.g., when executing @code{DOES>}) |
|
are applied to the latest defined word (as reported by @code{last} or |
|
@code{lastxt}), if possible, irrespective of the compilation wordlist. |
|
|
@item search order empty (@code{previous}): |
@item search order empty (@code{previous}): |
@code{abort" Vocstack empty"}. |
@code{abort" Vocstack empty"}. |
Line 2666 when @code{REVEAL} is executed (by @code
|
Line 3213 when @code{REVEAL} is executed (by @code
|
|
|
@end table |
@end table |
|
|
|
@node Model, Integrating Gforth, ANS conformance, Top |
@node Model, Emacs and Gforth, ANS conformance, Top |
|
@chapter Model |
@chapter Model |
|
|
@node Emacs and Gforth, Internals, Model, Top |
This chapter has yet to be written. It will contain information, on |
|
which internal structures you can rely. |
|
|
|
@node Integrating Gforth, Emacs and Gforth, Model, Top |
|
@chapter Integrating Gforth into C programs |
|
|
|
This is not yet implemented. |
|
|
|
Several people like to use Forth as scripting language for applications |
|
that are otherwise written in C, C++, or some other language. |
|
|
|
The Forth system ATLAST provides facilities for embedding it into |
|
applications; unfortunately it has several disadvantages: most |
|
implorantly, it is not based on ANS Forth, and it is apparently dead |
|
(i.e., not developed further and not supported). The facilities |
|
provided by Gforth in this area are inspired by ATLASTs facilities, so |
|
making the switch should not be hard. |
|
|
|
We also tried to design the interface such that it can easily be |
|
implemented by other Forth systems, so that we may one day arrive at a |
|
standardized interface. Such a standard interface would allow you to |
|
replace the Forth system without having to rewrite C code. |
|
|
|
You embed the Gforth interpreter by linking with the library |
|
@code{libgforth.a} (give the compiler the option @code{-lgforth}). All |
|
global symbols in this library that belong to the interface, have the |
|
prefix @code{forth_}. (Global symbols that are used internally have the |
|
prefix @code{gforth_}). |
|
|
|
You can include the declarations of Forth types and the functions and |
|
variables of the interface with @code{include <forth.h>}. |
|
|
|
Types. |
|
|
|
Variables. |
|
|
|
Data and FP Stack pointer. Area sizes. |
|
|
|
functions. |
|
|
|
forth_init(imagefile) |
|
forth_evaluate(string) exceptions? |
|
forth_goto(address) (or forth_execute(xt)?) |
|
forth_continue() (a corountining mechanism) |
|
|
|
Adding primitives. |
|
|
|
No checking. |
|
|
|
Signals? |
|
|
|
Accessing the Stacks |
|
|
|
@node Emacs and Gforth, Internals, Integrating Gforth, Top |
@chapter Emacs and Gforth |
@chapter Emacs and Gforth |
|
|
Gforth comes with @file{gforth.el}, an improved version of |
Gforth comes with @file{gforth.el}, an improved version of |
@file{forth.el} by Goran Rydqvist (icluded in the TILE package). The |
@file{forth.el} by Goran Rydqvist (included in the TILE package). The |
improvements are a better (but still not perfect) handling of |
improvements are a better (but still not perfect) handling of |
indentation. I have also added comment paragraph filling (@kbd{M-q}), |
indentation. I have also added comment paragraph filling (@kbd{M-q}), |
commenting (@kbd{C-x \}) and uncommenting (@kbd{C-u C-x \}) regions and |
commenting (@kbd{C-x \}) and uncommenting (@kbd{C-u C-x \}) regions and |
Line 2696 Also, if you @code{include} @file{etags.
|
Line 3295 Also, if you @code{include} @file{etags.
|
contains the definitions of all words defined afterwards. You can then |
contains the definitions of all words defined afterwards. You can then |
find the source for a word using @kbd{M-.}. Note that emacs can use |
find the source for a word using @kbd{M-.}. Note that emacs can use |
several tags files at the same time (e.g., one for the Gforth sources |
several tags files at the same time (e.g., one for the Gforth sources |
and one for your program). |
and one for your program, @pxref{Select Tags Table,,Selecting a Tags |
|
Table,emacs, Emacs Manual}). The TAGS file for the preloaded words is |
|
@file{$(datadir)/gforth/$(VERSION)/TAGS} (e.g., |
|
@file{/usr/local/share/gforth/0.2.0/TAGS}). |
|
|
To get all these benefits, add the following lines to your @file{.emacs} |
To get all these benefits, add the following lines to your @file{.emacs} |
file: |
file: |
Line 2712 file:
|
Line 3314 file:
|
Reading this section is not necessary for programming with Gforth. It |
Reading this section is not necessary for programming with Gforth. It |
should be helpful for finding your way in the Gforth sources. |
should be helpful for finding your way in the Gforth sources. |
|
|
|
The ideas in this section have also been published in the papers |
|
@cite{ANS fig/GNU/??? Forth} (in German) by Bernd Paysan, presented at |
|
the Forth-Tagung '93 and @cite{A Portable Forth Engine} by M. Anton |
|
Ertl, presented at EuroForth '93; the latter is available at |
|
@*@file{http://www.complang.tuwien.ac.at/papers/ertl93.ps.Z}. |
|
|
@menu |
@menu |
* Portability:: |
* Portability:: |
* Threading:: |
* Threading:: |
Line 2745 limitations: GNU C, the version of C pro
|
Line 3353 limitations: GNU C, the version of C pro
|
GNU C Manual}). Its labels as values feature (@pxref{Labels as Values, , |
GNU C Manual}). Its labels as values feature (@pxref{Labels as Values, , |
Labels as Values, gcc.info, GNU C Manual}) makes direct and indirect |
Labels as Values, gcc.info, GNU C Manual}) makes direct and indirect |
threading possible, its @code{long long} type (@pxref{Long Long, , |
threading possible, its @code{long long} type (@pxref{Long Long, , |
Double-Word Integers, gcc.info, GNU C Manual}) corresponds to Forths |
Double-Word Integers, gcc.info, GNU C Manual}) corresponds to Forth's |
double numbers. GNU C is available for free on all important (and many |
double numbers@footnote{Unfortunately, long longs are not implemented |
unimportant) UNIX machines, VMS, 80386s running MS-DOS, the Amiga, and |
properly on all machines (e.g., on alpha-osf1, long longs are only 64 |
the Atari ST, so a Forth written in GNU C can run on all these |
bits, the same size as longs (and pointers), but they should be twice as |
machines. |
long according to @ref{Long Long, , Double-Word Integers, gcc.info, GNU |
|
C Manual}). So, we had to implement doubles in C after all. Still, on |
|
most machines we can use long longs and achieve better performance than |
|
with the emulation package.}. GNU C is available for free on all |
|
important (and many unimportant) UNIX machines, VMS, 80386s running |
|
MS-DOS, the Amiga, and the Atari ST, so a Forth written in GNU C can run |
|
on all these machines. |
|
|
Writing in a portable language has the reputation of producing code that |
Writing in a portable language has the reputation of producing code that |
is slower than assembly. For our Forth engine we repeatedly looked at |
is slower than assembly. For our Forth engine we repeatedly looked at |
Line 2988 An important optimization for stack mach
|
Line 3602 An important optimization for stack mach
|
engines, is keeping one or more of the top stack items in |
engines, is keeping one or more of the top stack items in |
registers. If a word has the stack effect @var{in1}...@var{inx} @code{--} |
registers. If a word has the stack effect @var{in1}...@var{inx} @code{--} |
@var{out1}...@var{outy}, keeping the top @var{n} items in registers |
@var{out1}...@var{outy}, keeping the top @var{n} items in registers |
@itemize |
@itemize @bullet |
@item |
@item |
is better than keeping @var{n-1} items, if @var{x>=n} and @var{y>=n}, |
is better than keeping @var{n-1} items, if @var{x>=n} and @var{y>=n}, |
due to fewer loads from and stores to the stack. |
due to fewer loads from and stores to the stack. |
Line 3022 The TOS optimization makes the automatic
|
Line 3636 The TOS optimization makes the automatic
|
bit more complicated. Just replacing all occurrences of @code{sp[0]} by |
bit more complicated. Just replacing all occurrences of @code{sp[0]} by |
@code{TOS} is not sufficient. There are some special cases to |
@code{TOS} is not sufficient. There are some special cases to |
consider: |
consider: |
@itemize |
@itemize @bullet |
@item In the case of @code{dup ( w -- w w )} the generator must not |
@item In the case of @code{dup ( w -- w w )} the generator must not |
eliminate the store to the original location of the item on the stack, |
eliminate the store to the original location of the item on the stack, |
if the TOS optimization is turned on. |
if the TOS optimization is turned on. |
Line 3099 Sieve benchmark on a 486DX2/66 than Gfor
|
Line 3713 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 (direct threaded, compiled with @code{gcc-2.6.3} and |
Win32Forth and LMI's NT Forth, two systems written in assembly, and with |
@code{-DFORCE_REG}) with Win32Forth 1.2093, LMI's NT Forth (Beta, May |
two systems written in C: PFE-0.9.11 (compiled with @code{gcc-2.6.3} |
1994) and Eforth (with and without peephole (aka pinhole) optimization |
with the default configuration for Linux: @code{-O2 -fomit-frame-pointer |
of the threaded code); all these systems were written in assembly |
-DUSE_REGS}) and ThisForth Beta (compiled with gcc-2.6.3 -O3 |
language. We also compared Gforth with three systems written in C: |
-fomit-frame-pointer). We benchmarked Gforth, PFE and ThisForth on a |
PFE-0.9.14 (compiled with @code{gcc-2.6.3} with the default |
486DX2/66 under Linux. Kenneth O'Heskin kindly provided the results for |
configuration for Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS |
Win32Forth and NT Forth on a 486DX2/66 with similar memory performance |
-DUNROLL_NEXT}), ThisForth Beta (compiled with gcc-2.6.3 -O3 |
under Windows NT. |
-fomit-frame-pointer; ThisForth employs peephole optimization of the |
|
threaded code) and TILE (compiled with @code{make opt}). We benchmarked |
|
Gforth, PFE, ThisForth and TILE on a 486DX2/66 under Linux. Kenneth |
|
O'Heskin kindly provided the results for Win32Forth and NT Forth on a |
|
486DX2/66 with similar memory performance under Windows NT. Marcel |
|
Hendrix ported Eforth to Linux, then extended it to run the benchmarks, |
|
added the peephole optimizer, ran the benchmarks and reported the |
|
results. |
|
|
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 |
been translated into Forth by Martin Fraeman; we used the versions |
been translated into Forth by Martin Fraeman; we used the versions |
included in the TILE Forth package; and a recursive Fibonacci number |
included in the TILE Forth package, but with bigger data set sizes; and |
computation for benchmark calling performance. The following table shows |
a recursive Fibonacci number computation for benchmarking calling |
the time taken for the benchmarks scaled by the time taken by Gforth (in |
performance. The following table shows the time taken for the benchmarks |
other words, it shows the speedup factor that Gforth achieved over the |
scaled by the time taken by Gforth (in other words, it shows the speedup |
other systems). |
factor that Gforth achieved over the other systems). |
|
|
@example |
@example |
relative Win32- NT This- |
relative Win32- NT eforth This- |
time Gforth Forth Forth PFE Forth |
time Gforth Forth Forth eforth +opt PFE Forth TILE |
sieve 1.00 1.30 1.07 1.67 2.98 |
sieve 1.00 1.39 1.14 1.39 0.85 1.58 3.18 8.58 |
bubble 1.00 1.30 1.40 1.66 |
bubble 1.00 1.31 1.41 1.48 0.88 1.50 3.88 |
matmul 1.00 1.40 1.29 2.24 |
matmul 1.00 1.47 1.35 1.46 1.16 1.58 4.09 |
fib 1.00 1.44 1.26 1.82 2.82 |
fib 1.00 1.52 1.34 1.22 1.13 1.74 2.99 4.30 |
@end example |
@end example |
|
|
You may find the good performance of Gforth compared with the systems |
You may find the good performance of Gforth compared with the systems |
Line 3136 method for relocating the Forth image: l
|
Line 3757 method for relocating the Forth image: l
|
the actual addresses at run time, resulting in two address computations |
the actual addresses at run time, resulting in two address computations |
per NEXT (@pxref{System Architecture}). |
per NEXT (@pxref{System Architecture}). |
|
|
The speedup of Gforth over PFE and ThisForth can be easily explained |
Only Eforth with the peephole optimizer performs comparable to |
with the self-imposed restriction to standard C (although the measured |
Gforth. The speedups achieved with peephole optimization of threaded |
implementation of PFE uses a GNU C extension: global register |
code are quite remarkable. Adding a peephole optimizer to Gforth should |
variables), which makes efficient threading impossible. Moreover, |
cause similar speedups. |
current C compilers have a hard time optimizing other aspects of the |
|
ThisForth source. |
The speedup of Gforth over PFE, ThisForth and TILE can be easily |
|
explained with the self-imposed restriction to standard C, which makes |
|
efficient threading impossible (however, the measured implementation of |
|
PFE uses a GNU C extension: @ref{Global Reg Vars, , Defining Global |
|
Register Variables, gcc.info, GNU C Manual}). Moreover, current C |
|
compilers have a hard time optimizing other aspects of the ThisForth |
|
and the TILE source. |
|
|
Note that the performance of Gforth on 386 architecture processors |
Note that the performance of Gforth on 386 architecture processors |
varies widely with the version of @code{gcc} used. E.g., @code{gcc-2.5.8} |
varies widely with the version of @code{gcc} used. E.g., @code{gcc-2.5.8} |
Line 3150 machine registers by itself and would no
|
Line 3777 machine registers by itself and would no
|
register declarations, giving a 1.3 times slower engine (on a 486DX2/66 |
register declarations, giving a 1.3 times slower engine (on a 486DX2/66 |
running the Sieve) than the one measured above. |
running the Sieve) than the one measured above. |
|
|
@node Bugs, Pedigree, Internals, Top |
In @cite{Translating Forth to Efficient C} by M. Anton Ertl and Martin |
|
Maierhofer (presented at EuroForth '95), an indirect threaded version of |
|
Gforth is compared with Win32Forth, NT Forth, PFE, and ThisForth; that |
|
version of Gforth is 2\%@minus{}8\% slower on a 486 than the version |
|
used here. The paper available at |
|
@*@file{http://www.complang.tuwien.ac.at/papers/ertl&maierhofer95.ps.gz}; |
|
it also contains numbers for some native code systems. You can find |
|
numbers for Gforth on various machines in @file{Benchres}. |
|
|
|
@node Bugs, Origin, Internals, Top |
@chapter Bugs |
@chapter Bugs |
|
|
Known bugs are described in the file BUGS in the Gforth distribution. |
Known bugs are described in the file BUGS in the Gforth distribution. |
|
|
If you find a bug, please send a bug report to !!. A bug report should |
If you find a bug, please send a bug report to |
|
@code{bug-gforth@@gnu.ai.mit.edu}. A bug report should |
describe the Gforth version used (it is announced at the start of an |
describe the Gforth version used (it is announced at the start of an |
interactive Gforth session), the machine and operating system (on Unix |
interactive Gforth session), the machine and operating system (on Unix |
systems you can use @code{uname -a} to produce this information), the |
systems you can use @code{uname -a} to produce this information), the |
installation options (!! a way to find them out), and a complete list of |
installation options (send the @code{config.status} file), and a |
changes you (or your installer) have made to the Gforth sources (if |
complete list of changes you (or your installer) have made to the Gforth |
any); it should contain a program (or a sequence of keyboard commands) |
sources (if any); it should contain a program (or a sequence of keyboard |
that reproduces the bug and a description of what you think constitutes |
commands) that reproduces the bug and a description of what you think |
the buggy behaviour. |
constitutes the buggy behaviour. |
|
|
For a thorough guide on reporting bugs read @ref{Bug Reporting, , How |
For a thorough guide on reporting bugs read @ref{Bug Reporting, , How |
to Report Bugs, gcc.info, GNU C Manual}. |
to Report Bugs, gcc.info, GNU C Manual}. |
|
|
|
|
@node Pedigree, Word Index, Bugs, Top |
@node Origin, Word Index, Bugs, Top |
@chapter Pedigree |
@chapter Authors and Ancestors of Gforth |
|
|
Gforth descends from BigForth (1993) and fig-Forth. Gforth and PFE (by |
@section Authors and Contributors |
Dirk Zoller) will cross-fertilize each other. Of course, a significant part of the design of Gforth was prescribed by ANS Forth. |
|
|
|
Bernd Paysan wrote BigForth, a child of VolksForth. |
The Gforth project was started in mid-1992 by Bernd Paysan and Anton |
|
Ertl. The third major author was Jens Wilke. Lennart Benschop (who was |
|
one of Gforth's first users, in mid-1993) and Stuart Ramsden inspired us |
|
with their continuous feedback. Lennart Benshop contributed |
|
@file{glosgen.fs}, while Stuart Ramsden has been working on automatic |
|
support for calling C libraries. Helpful comments also came from Paul |
|
Kleinrubatscher, Christian Pirker, Dirk Zoller and Marcel Hendrix. |
|
|
|
Gforth also owes a lot to the authors of the tools we used (GCC, CVS, |
|
and autoconf, among others), and to the creators of the Internet: Gforth |
|
was developed across the Internet, and its authors have not met |
|
physically yet. |
|
|
|
@section Pedigree |
|
|
|
Gforth descends from BigForth (1993) and fig-Forth. Gforth and PFE (by |
|
Dirk Zoller) will cross-fertilize each other. Of course, a significant |
|
part of the design of Gforth was prescribed by ANS Forth. |
|
|
VolksForth descends from F83. !! Authors? When? |
Bernd Paysan wrote BigForth, a descendent from TurboForth, an unreleased |
|
32 bit native code version of VolksForth for the Atari ST, written |
|
mostly by Dietrich Weineck. |
|
|
|
VolksForth descends from F83. It was written by Klaus Schleisiek, Bernd |
|
Pennemann, Georg Rehfeld and Dietrich Weineck for the C64 (called |
|
UltraForth there) in the mid-80s and ported to the Atari ST in 1986. |
|
|
Laxen and Perry wrote F83 as a model implementation of the |
Henry Laxen and Mike Perry wrote F83 as a model implementation of the |
Forth-83 standard. !! Pedigree? When? |
Forth-83 standard. !! Pedigree? When? |
|
|
A team led by Bill Ragsdale implemented fig-Forth on many processors in |
A team led by Bill Ragsdale implemented fig-Forth on many processors in |
1979. Dean Sanderson and Bill Ragsdale developed the original |
1979. Robert Selzer and Bill Ragsdale developed the original |
implementation of fig-Forth based on microForth. |
implementation of fig-Forth for the 6502 based on microForth. |
|
|
!! microForth pedigree |
The principal architect of microForth was Dean Sanderson. microForth was |
|
FORTH, Inc.'s first off-the-shelf product. It was developped in 1976 for |
|
the 1802, and subsequently implemented on the 8080, the 6800 and the |
|
Z80. |
|
|
|
All earlier Forth systems were custom-made, usually by Charles Moore, |
|
who discovered (as he puts it) Forth during the late 60s. The first full |
|
Forth existed in 1971. |
|
|
A part of the information in this section comes from @cite{The Evolution |
A part of the information in this section comes from @cite{The Evolution |
of Forth} by Elizabeth D. Rather, Donald R. Colburn and Charles |
of Forth} by Elizabeth D. Rather, Donald R. Colburn and Charles |
Line 3194 H. Moore, presented at the HOPL-II confe
|
Line 3860 H. Moore, presented at the HOPL-II confe
|
Notices 28(3), 1993. You can find more historical and genealogical |
Notices 28(3), 1993. You can find more historical and genealogical |
information about Forth there. |
information about Forth there. |
|
|
@node Word Index, Node Index, Pedigree, Top |
@node Word Index, Node Index, Origin, 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 |
|
|