--- gforth/Attic/gforth.ds 1995/11/30 18:04:27 1.26 +++ gforth/Attic/gforth.ds 1996/05/13 16:36:56 1.33 @@ -7,9 +7,9 @@ @comment %**end of header (This is for running Texinfo on a region.) @ifinfo -This file documents Gforth 0.1 +This file documents Gforth 0.2 -Copyright @copyright{} 1995 Free Software Foundation, Inc. +Copyright @copyright{} 1995,1996 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice @@ -41,7 +41,7 @@ Copyright @copyright{} 1995 Free Softwar @sp 10 @center @titlefont{Gforth Manual} @sp 2 -@center for version 0.1 +@center for version 0.2 @sp 2 @center Anton Ertl @center Bernd Paysan @@ -51,7 +51,7 @@ Copyright @copyright{} 1995 Free Softwar @comment The following two commands start the copyright page. @page @vskip 0pt plus 1filll -Copyright @copyright{} 1995 Free Software Foundation, Inc. +Copyright @copyright{} 1995,1996 Free Software Foundation, Inc. @comment !! Published by ... or You can get a copy of this manual ... @@ -77,7 +77,7 @@ Copyright @copyright{} 1995 Free Softwar @node Top, License, (dir), (dir) @ifinfo Gforth is a free implementation of ANS Forth available on many -personal machines. This manual corresponds to version 0.1. +personal machines. This manual corresponds to version 0.2. @end ifinfo @menu @@ -91,7 +91,7 @@ personal machines. This manual correspon * Emacs and Gforth:: The Gforth Mode * Internals:: Implementation details * Bugs:: How to report them -* Pedigree:: Ancestors of Gforth +* Origin:: Authors and ancestors of Gforth * Word Index:: An item for each Forth word * Node Index:: An item for each node @end menu @@ -1141,8 +1141,11 @@ system that only supplies @code{THEN} is Forth's @code{THEN} has the meaning 2b, whereas @code{THEN} in Pascal and many other programming languages has the meaning 3d.] -We also provide the words @code{?dup-if} and @code{?dup-0=-if}, so you -can avoid using @code{?dup}. +Gforth also provides the words @code{?dup-if} and @code{?dup-0=-if}, so +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 @var{n} @@ -1234,13 +1237,7 @@ arithmetic). This behaviour is usually n Gforth offers @code{+DO} and @code{U+DO} (as replacements for @code{?DO}), which do not enter the loop if @var{start} is greater than @var{limit}; @code{+DO} is for signed loop parameters, @code{U+DO} for -unsigned loop parameters. These words can be implemented easily on -standard systems, so using them does not make your programs hard to -port; e.g.: -@example -: +DO ( compile-time: -- do-sys; run-time: n1 n2 -- ) - POSTPONE over POSTPONE min POSTPONE ?DO ; immediate -@end example +unsigned loop parameters. @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 @@ -1268,16 +1265,10 @@ between @var{limit+1} and @var{limit} is @code{ 0 0 -DO i . 1 -LOOP} prints nothing -Another alternative is @code{@var{n} S+LOOP}, where the negative -case behaves symmetrical to the positive case: - -@code{-2 0 -DO i . -1 S+LOOP} prints @code{0 -1} - -The loop is terminated when the border between @var{limit@minus{}sgn(n)} -and @var{limit} is crossed. Unfortunately, neither @code{-LOOP} nor -@code{S+LOOP} are part of the ANS Forth standard, and they are not easy -to implement using standard words. If you want to write standard -programs, just avoid counting down. +Unfortunately, @code{+DO}, @code{U+DO}, @code{-DO}, @code{U-DO} and +@code{-LOOP} are not in the ANS Forth standard. However, an +implementation for these words that uses only standard words is provided +in @file{compat/loops.fs}. @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 @@ -1300,7 +1291,8 @@ This is the preferred loop of native cod lazy to optimize @code{?DO} loops properly. In Gforth, this loop 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 -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 @subsection Arbitrary control structures @@ -1336,6 +1328,12 @@ doc-else doc-while 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: doc-?do @@ -1346,7 +1344,6 @@ doc-u-do doc-do doc-for doc-loop -doc-s+loop doc-+loop doc--loop doc-next @@ -1411,7 +1408,7 @@ while repeat @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 necessary to define them. @@ -1736,8 +1733,8 @@ E.g., a definition using @code{TO} might : strcmp @{ addr1 u1 addr2 u2 -- n @} u1 u2 min 0 ?do - addr1 c@ addr2 c@ - ?dup - if + addr1 c@ addr2 c@ - + ?dup-if unloop exit then addr1 char+ TO addr1 @@ -1759,8 +1756,8 @@ are initialized with the right value for addr1 addr2 u1 u2 min 0 ?do @{ s1 s2 @} - s1 c@ s2 c@ - ?dup - if + s1 c@ s2 c@ - + ?dup-if unloop exit then s1 char+ s2 char+ @@ -1939,8 +1936,8 @@ name produces their value. Their value c 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 -another ANS Forth system, use @file{anslocal.fs} to implement the syntax -on the other system. +another ANS Forth system, use @file{compat/anslocal.fs} to implement the +syntax on the other system. Note that a syntax shown in the standard, section A.13 looks similar, but is quite different in having the order of locals @@ -2528,9 +2525,14 @@ The next invocation of a parsing word re 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}: -If the argument input source is a valid input source then it gets -restored. Otherwise the result is undefined. -@comment causes @code{-12 THROW}, which, unless caught, issues the message "argument type mismatch" and aborts. !! not all of the state is restored (e.g., sourcefilename). +@code{-12 THROW}. Note that, once an input file is closed (e.g., because +the end of the file was reached), its source-id may be +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: Deallocation with @code{allot} is not checked. This typically resuls in @@ -3196,9 +3198,11 @@ Not implemented (yet). @table @i @item changing the compilation wordlist (during compilation): -The definition is put into the wordlist that is the compilation wordlist -when @code{REVEAL} is executed (by @code{;}, @code{DOES>}, -@code{RECURSIVE}, etc.). +The word is entered into the wordlist that was the compilation wordlist +at the start of the definition. Any changes to the name field (e.g., +@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}): @code{abort" Vocstack empty"}. @@ -3216,7 +3220,7 @@ when @code{REVEAL} is executed (by @code @chapter Emacs and Gforth 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 indentation. I have also added comment paragraph filling (@kbd{M-q}), commenting (@kbd{C-x \}) and uncommenting (@kbd{C-u C-x \}) regions and @@ -3238,7 +3242,10 @@ Also, if you @code{include} @file{etags. 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 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} file: @@ -3293,11 +3300,17 @@ limitations: GNU C, the version of C pro GNU C Manual}). Its labels as values feature (@pxref{Labels as Values, , Labels as Values, gcc.info, GNU C Manual}) makes direct and indirect threading possible, its @code{long long} type (@pxref{Long Long, , -Double-Word Integers, gcc.info, GNU C Manual}) corresponds to Forths -double numbers. 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. +Double-Word Integers, gcc.info, GNU C Manual}) corresponds to Forth's +double numbers@footnote{Unfortunately, long longs are not implemented +properly on all machines (e.g., on alpha-osf1, long longs are only 64 +bits, the same size as longs (and pointers), but they should be twice as +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 is slower than assembly. For our Forth engine we repeatedly looked at @@ -3651,34 +3664,35 @@ Gforth (direct threaded, compiled with @ @code{-DFORCE_REG}) with Win32Forth 1.2093, LMI's NT Forth (Beta, May 1994) and Eforth (with and without peephole (aka pinhole) optimization of the threaded code); all these systems were written in assembly -language. We also compared Gforth with two systems written in C: -PFE-0.9.11 (compiled with @code{gcc-2.6.3} with the default -configuration for Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS}) and -ThisForth Beta (compiled with gcc-2.6.3 -O3 -fomit-frame-pointer; -ThisForth employs peephole optimization of the threaded code). We -benchmarked Gforth, PFE and ThisForth 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. +language. We also compared Gforth with three systems written in C: +PFE-0.9.14 (compiled with @code{gcc-2.6.3} with the default +configuration for Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS +-DUNROLL_NEXT}), ThisForth Beta (compiled with gcc-2.6.3 -O3 +-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 matrix multiplication come from the Stanford integer benchmarks and have been translated into Forth by Martin Fraeman; we used the versions -included in the TILE Forth package; and a recursive Fibonacci number -computation for benchmarking calling performance. The following table shows -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 systems). +included in the TILE Forth package, but with bigger data set sizes; and +a recursive Fibonacci number computation for benchmarking calling +performance. The following table shows 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 systems). @example -relative Win32- NT eforth This- -time Gforth Forth Forth eforth +opt PFE Forth -sieve 1.00 1.39 1.14 1.39 0.85 1.78 3.18 -bubble 1.00 1.33 1.43 1.51 0.89 1.70 -matmul 1.00 1.43 1.31 1.42 1.12 2.28 -fib 1.00 1.55 1.36 1.24 1.15 1.97 3.04 +relative Win32- NT eforth This- + time Gforth Forth Forth eforth +opt PFE Forth TILE +sieve 1.00 1.39 1.14 1.39 0.85 1.58 3.18 8.58 +bubble 1.00 1.31 1.41 1.48 0.88 1.50 3.88 +matmul 1.00 1.47 1.35 1.46 1.16 1.58 4.09 +fib 1.00 1.52 1.34 1.22 1.13 1.74 2.99 4.30 @end example You may find the good performance of Gforth compared with the systems @@ -3695,12 +3709,13 @@ Gforth. The speedups achieved with peeph code are quite remarkable. Adding a peephole optimizer to Gforth should cause similar speedups. -The speedup of Gforth over PFE and ThisForth can be easily explained -with the self-imposed restriction to standard C (although the measured -implementation of PFE uses a GNU C extension: global register -variables), which makes efficient threading impossible. Moreover, -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 varies widely with the version of @code{gcc} used. E.g., @code{gcc-2.5.8} @@ -3718,13 +3733,13 @@ used here. The paper available at it also contains numbers for some native code systems. You can find numbers for Gforth on various machines in @file{Benchres}. -@node Bugs, Pedigree, Internals, Top +@node Bugs, Origin, Internals, Top @chapter Bugs Known bugs are described in the file BUGS in the Gforth distribution. If you find a bug, please send a bug report to -@code{gforth-bugs@@mips.complang.tuwien.ac.at}. A bug report should +@code{bug-gforth@@gnu.ai.mit.edu}. A bug report should describe the Gforth version used (it is announced at the start of an interactive Gforth session), the machine and operating system (on Unix systems you can use @code{uname -a} to produce this information), the @@ -3738,8 +3753,25 @@ For a thorough guide on reporting bugs r to Report Bugs, gcc.info, GNU C Manual}. -@node Pedigree, Word Index, Bugs, Top -@chapter Pedigree +@node Origin, Word Index, Bugs, Top +@chapter Authors and Ancestors of Gforth + +@section Authors and Contributors + +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 @@ -3766,7 +3798,8 @@ the 1802, and subsequently implemented o Z80. All earlier Forth systems were custom-made, usually by Charles Moore, -who discovered (as he puts it) Forth in the late 60s. +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 of Forth} by Elizabeth D. Rather, Donald R. Colburn and Charles @@ -3774,7 +3807,7 @@ H. Moore, presented at the HOPL-II confe Notices 28(3), 1993. You can find more historical and genealogical information about Forth there. -@node Word Index, Node Index, Pedigree, Top +@node Word Index, Node Index, Origin, Top @chapter Word Index This index is as incomplete as the manual. Each word is listed with