version 1.20, 1995/10/29 21:35:11
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version 1.28, 1995/12/23 16:21:57
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@ifinfo |
@ifinfo |
This file documents Gforth 0.1 |
This file documents Gforth 0.1 |
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Copyright @copyright{} 1994 Gforth Development Group |
Copyright @copyright{} 1995 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} |
Line 43 Copyright @copyright{} 1994 Gforth Devel
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Line 44 Copyright @copyright{} 1994 Gforth Devel
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@center for version 0.1 |
@center for version 0.1 |
@sp 2 |
@sp 2 |
@center Anton Ertl |
@center Anton Ertl |
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@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 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 0.1. |
@end ifinfo |
@end ifinfo |
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@menu |
@menu |
Line 487 library. If this is what you want to do
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Line 489 library. If this is what you want to do
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Public License instead of this License. |
Public License instead of this License. |
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@iftex |
@iftex |
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@node Preface |
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@comment node-name, next, previous, up |
@unnumbered Preface |
@unnumbered Preface |
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@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 555 can also get it from Global Engineering
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Line 560 can also get it from Global Engineering
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for publication is available electronically and for free in some MS Word |
for publication is available electronically and for free in some MS Word |
format, and it has been converted to HTML. Some pointers to these |
format, and it has been converted to HTML. Some pointers to these |
versions can be found through |
versions can be found through |
http://www.complang.tuwien.ac.at/projects/forth.html. |
@*@file{http://www.complang.tuwien.ac.at/projects/forth.html}. |
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|
@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 642 Forth words, you have to quote them or u
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Line 647 Forth words, you have to quote them or u
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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. |
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If you have several versions of Gforth installed, @code{gforth} will |
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invoke the version that was installed last. @code{gforth-@var{version}} |
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invokes a specific version. You may want to use the option |
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@code{--path}, if your environment contains the variable |
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@code{GFORTHPATH}. |
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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 1434 laden with restrictions. Therefore, we p
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Line 1445 laden with restrictions. Therefore, we p
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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). |
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The ideas in this section have also been published in the paper |
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@cite{Automatic Scoping of Local Variables} by M. Anton Ertl, presented |
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at EuroForth '94; it is available at |
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@*@file{http://www.complang.tuwien.ac.at/papers/ertl94l.ps.gz}. |
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@menu |
@menu |
* Gforth locals:: |
* Gforth locals:: |
* ANS Forth locals:: |
* ANS Forth locals:: |
Line 2073 machine code), and for defining the the
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Line 2089 machine code), and for defining the the
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nature of Gforth poses a few problems: First of all. Gforth runs on |
nature of Gforth poses a few problems: First of all. Gforth runs on |
several architectures, so it can provide no standard assembler. What's |
several architectures, so it can provide no standard assembler. What's |
worse is that the register allocation not only depends on the processor, |
worse is that the register allocation not only depends on the processor, |
but also on the gcc version and options used. |
but also on the @code{gcc} version and options used. |
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The words Gforth offers encapsulate some system dependences (e.g., the |
The words that Gforth offers encapsulate some system dependences (e.g., the |
header structure), so a system-independent assembler may be used in |
header structure), so a system-independent assembler may be used in |
Gforth. If you do not have an assembler, you can compile machine code |
Gforth. If you do not have an assembler, you can compile machine code |
directly with @code{,} and @code{c,}. |
directly with @code{,} and @code{c,}. |
Line 2093 These words are rarely used. Therefore t
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Line 2109 These words are rarely used. Therefore t
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which is usually not loaded (except @code{flush-icache}, which is always |
which is usually not loaded (except @code{flush-icache}, which is always |
present). You can load them with @code{require code.fs}. |
present). You can load them with @code{require code.fs}. |
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In the assembly code you will want to refer to the inner interpreter's |
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registers (e.g., the data stack pointer) and you may want to use other |
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registers for temporary storage. Unfortunately, the register allocation |
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is installation-dependent. |
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The easiest solution is to use explicit register declarations |
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(@pxref{Explicit Reg Vars, , Variables in Specified Registers, gcc.info, |
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GNU C Manual}) for all of the inner interpreter's registers: You have to |
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compile Gforth with @code{-DFORCE_REG} (configure option |
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@code{--enable-force-reg}) and the appropriate declarations must be |
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present in the @code{machine.h} file (see @code{mips.h} for an example; |
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you can find a full list of all declarable register symbols with |
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@code{grep register engine.c}). If you give explicit registers to all |
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variables that are declared at the beginning of @code{engine()}, you |
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should be able to use the other caller-saved registers for temporary |
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storage. Alternatively, you can use the @code{gcc} option |
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@code{-ffixed-REG} (@pxref{Code Gen Options, , Options for Code |
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Generation Conventions, gcc.info, GNU C Manual}) to reserve a register |
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(however, this restriction on register allocation may slow Gforth |
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significantly). |
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If this solution is not viable (e.g., because @code{gcc} does not allow |
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you to explicitly declare all the registers you need), you have to find |
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out by looking at the code where the inner interpreter's registers |
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reside and which registers can be used for temporary storage. You can |
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get an assembly listing of the engine's code with @code{make engine.s}. |
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In any case, it is good practice to abstract your assembly code from the |
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actual register allocation. E.g., if the data stack pointer resides in |
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register @code{$17}, create an alias for this register called @code{sp}, |
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and use that in your assembly code. |
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Another option for implementing normal and defining words efficiently |
Another option for implementing normal and defining words efficiently |
is: adding the wanted functionality to the source of Gforth. For normal |
is: adding the wanted functionality to the source of Gforth. For normal |
words you just have to edit @file{primitives}, defining words (for fast |
words you just have to edit @file{primitives}, defining words (for fast |
defined words) probably require changes in @file{engine.c}, |
defined words) may require changes in @file{engine.c}, |
@file{kernal.fs}, @file{prims2x.fs}, and possibly @file{cross.fs}. |
@file{kernal.fs}, @file{prims2x.fs}, and possibly @file{cross.fs}. |
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Line 2369 characters is determined by the locale y
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Line 2417 characters is determined by the locale y
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@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{/}). |
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@item values of @code{STATE} when true: |
@item values of @code{STATE} when true: |
Line 2480 The next invocation of a parsing word re
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Line 2528 The next invocation of a parsing word re
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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. |
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@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 |
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closed file may lead to unpredictable results instead of a @code{-12 |
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THROW}. |
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In the future, Gforth may be able to retore input source specifications |
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from other than the current input soruce. |
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@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 2554 Not checked. As usual, you can expect me
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Line 2607 Not checked. As usual, you can expect me
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None. |
None. |
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@item operator's terminal facilities available: |
@item operator's terminal facilities available: |
!!?? |
After processing the command line, Gforth goes into interactive mode, |
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and you can give commands to Gforth interactively. The actual facilities |
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available depend on how you invoke Gforth. |
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@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. |
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@item return stack space available: |
@item return stack space available: |
!!?? |
By default 16 KBytes. The default can be overridden with the @code{-r} |
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switch (@pxref{Invocation}) when Gforth starts up. |
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@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 2882 System dependent; @code{REPRESENT} is im
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Line 2938 System dependent; @code{REPRESENT} is im
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function @code{ecvt()} and inherits its behaviour in this respect. |
function @code{ecvt()} and inherits its behaviour in this respect. |
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@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 |
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compiler. IEEE-FP-based (i.e., most) systems by default round to |
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nearest, and break ties by rounding to even (i.e., such that the last |
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bit of the mantissa is 0). |
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@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 3184 Also, if you @code{include} @file{etags.
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Line 3243 Also, if you @code{include} @file{etags.
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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 |
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Table,emacs, Emacs Manual}). The TAGS file for the preloaded words is |
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@file{$(datadir)/gforth/$(VERSION)/TAGS} (e.g., |
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@file{/usr/local/share/gforth/0.2/TAGS}). |
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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 3200 file:
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Line 3262 file:
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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. |
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The ideas in this section have also been published in the papers |
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@cite{ANS fig/GNU/??? Forth} (in German) by Bernd Paysan, presented at |
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the Forth-Tagung '93 and @cite{A Portable Forth Engine} by M. Anton |
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Ertl, presented at EuroForth '93; the latter is available at |
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@*@file{http://www.complang.tuwien.ac.at/papers/ertl93.ps.Z}. |
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@menu |
@menu |
* Portability:: |
* Portability:: |
* Threading:: |
* Threading:: |
Line 3587 Sieve benchmark on a 486DX2/66 than Gfor
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Line 3655 Sieve benchmark on a 486DX2/66 than Gfor
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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 1.2093 and LMI's NT Forth (Beta, May 1994), two systems |
@code{-DFORCE_REG}) with Win32Forth 1.2093, LMI's NT Forth (Beta, May |
written in assembly, and with two systems written in C: PFE-0.9.11 |
1994) and Eforth (with and without peephole (aka pinhole) optimization |
(compiled with @code{gcc-2.6.3} with the default configuration for |
of the threaded code); all these systems were written in assembly |
Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS}) and ThisForth Beta |
language. We also compared Gforth with two systems written in C: |
(compiled with gcc-2.6.3 -O3 -fomit-frame-pointer). We benchmarked |
PFE-0.9.11 (compiled with @code{gcc-2.6.3} with the default |
Gforth, PFE and ThisForth on a 486DX2/66 under Linux. Kenneth O'Heskin |
configuration for Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS}) and |
kindly provided the results for Win32Forth and NT Forth on a 486DX2/66 |
ThisForth Beta (compiled with gcc-2.6.3 -O3 -fomit-frame-pointer; |
with similar memory performance under Windows NT. |
ThisForth employs peephole optimization of the threaded code). We |
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benchmarked Gforth, PFE and ThisForth on a 486DX2/66 under |
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Linux. Kenneth O'Heskin kindly provided the results for Win32Forth and |
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NT Forth on a 486DX2/66 with similar memory performance under Windows |
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NT. Marcel Hendrix ported Eforth to Linux, then extended it to run the |
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benchmarks, added the peephole optimizer, ran the benchmarks and |
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reported the results. |
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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; and a recursive Fibonacci number |
computation for benchmark calling performance. The following table shows |
computation for benchmarking calling performance. The following table shows |
the time taken for the benchmarks scaled by the time taken by Gforth (in |
the time taken for the benchmarks scaled by the time taken by Gforth (in |
other words, it shows the speedup factor that Gforth achieved over the |
other words, it shows the speedup factor that Gforth achieved over the |
other systems). |
other systems). |
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@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 |
sieve 1.00 1.30 1.07 1.67 2.98 |
sieve 1.00 1.39 1.14 1.39 0.85 1.78 3.18 |
bubble 1.00 1.30 1.40 1.66 |
bubble 1.00 1.33 1.43 1.51 0.89 1.70 |
matmul 1.00 1.40 1.29 2.24 |
matmul 1.00 1.43 1.31 1.42 1.12 2.28 |
fib 1.00 1.44 1.26 1.82 2.82 |
fib 1.00 1.55 1.36 1.24 1.15 1.97 3.04 |
@end example |
@end example |
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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 3624 method for relocating the Forth image: l
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Line 3698 method for relocating the Forth image: l
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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}). |
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Only Eforth with the peephole optimizer performs comparable to |
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Gforth. The speedups achieved with peephole optimization of threaded |
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code are quite remarkable. Adding a peephole optimizer to Gforth should |
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cause similar speedups. |
|
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The speedup of Gforth over PFE and ThisForth can be easily explained |
The speedup of Gforth over PFE and ThisForth can be easily explained |
with the self-imposed restriction to standard C (although the measured |
with the self-imposed restriction to standard C (although the measured |
implementation of PFE uses a GNU C extension: global register |
implementation of PFE uses a GNU C extension: global register |
Line 3638 machine registers by itself and would no
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Line 3717 machine registers by itself and would no
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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. |
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In @cite{Translating Forth to Efficient C} by M. Anton Ertl and Martin |
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Maierhofer (presented at EuroForth '95), an indirect threaded version of |
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Gforth is compared with Win32Forth, NT Forth, PFE, and ThisForth; that |
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version of Gforth is 2\%@minus{}8\% slower on a 486 than the version |
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used here. The paper available at |
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@*@file{http://www.complang.tuwien.ac.at/papers/ertl&maierhofer95.ps.gz}; |
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it also contains numbers for some native code systems. You can find |
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numbers for Gforth on various machines in @file{Benchres}. |
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@node Bugs, Pedigree, Internals, Top |
@node Bugs, Pedigree, Internals, Top |
@chapter Bugs |
@chapter Bugs |
|
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Known bugs are described in the file BUGS in the Gforth distribution. |
Known bugs are described in the file BUGS in the Gforth distribution. |
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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 |
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@code{gforth-bugs@@mips.complang.tuwien.ac.at}. 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. |
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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}. |
Line 3661 to Report Bugs, gcc.info, GNU C Manual}.
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Line 3750 to Report Bugs, gcc.info, GNU C Manual}.
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@chapter Pedigree |
@chapter Pedigree |
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Gforth descends from BigForth (1993) and fig-Forth. Gforth and PFE (by |
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. |
Dirk Zoller) will cross-fertilize each other. Of course, a significant |
|
part of the design of Gforth was prescribed by ANS Forth. |
|
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Bernd Paysan wrote BigForth, a child of VolksForth. |
Bernd Paysan wrote BigForth, a descendent from TurboForth, an unreleased |
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32 bit native code version of VolksForth for the Atari ST, written |
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mostly by Dietrich Weineck. |
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|
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VolksForth descends from F83. It was written by Klaus Schleisiek, Bernd |
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Pennemann, Georg Rehfeld and Dietrich Weineck for the C64 (called |
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UltraForth there) in the mid-80s and ported to the Atari ST in 1986. |
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VolksForth descends from F83. !! Authors? When? |
Hennry Laxen and Mike Perry wrote F83 as a model implementation of the |
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Laxen and Perry wrote F83 as a model implementation of the |
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Forth-83 standard. !! Pedigree? When? |
Forth-83 standard. !! Pedigree? When? |
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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. |
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|
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The principal architect of microForth was Dean Sanderson. microForth was |
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FORTH, Inc.'s first off-the-shelf product. It was developped in 1976 for |
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the 1802, and subsequently implemented on the 8080, the 6800 and the |
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Z80. |
|
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!! microForth pedigree |
All earlier Forth systems were custom-made, usually by Charles Moore, |
|
who discovered (as he puts it) Forth in the late 60s. |
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|
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 |