--- gforth/Attic/gforth.ds 1996/01/07 17:22:09 1.29 +++ gforth/Attic/gforth.ds 1996/01/25 16:45:50 1.30 @@ -7,7 +7,7 @@ @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. @@ -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 @@ -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 @@ -1234,13 +1234,7 @@ 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 +1262,10 @@ 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 +1288,8 @@ 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 @@ -1346,7 +1335,6 @@ doc-u-do doc-do doc-for doc-loop -doc-s+loop doc-+loop doc--loop doc-next @@ -1411,7 +1399,7 @@ 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. @@ -1939,8 +1927,8 @@ 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 @@ -3659,34 +3647,34 @@ 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: +language. We also compared Gforth with three 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 +configuration for Linux: @code{-O2 -fomit-frame-pointer -DUSE_REGS}), 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. +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 1.78 3.18 8.58 +bubble 1.00 1.31 1.41 1.48 0.88 1.67 3.88 +matmul 1.00 1.47 1.35 1.46 1.16 2.36 4.09 +fib 1.00 1.52 1.34 1.22 1.13 1.93 2.99 4.30 @end example You may find the good performance of Gforth compared with the systems @@ -3703,12 +3691,13 @@ 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} @@ -3752,13 +3741,18 @@ to Report Bugs, gcc.info, GNU C Manual}. @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 also -was one of Gforth's first users, in mid-1993) and Stuart Ramsden -inspired us with their continuous feedback. Lennart Benshop contributed +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 @@ -3786,7 +3780,8 @@ 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