version 1.6, 1995/01/18 18:41:37
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version 1.12, 1995/03/13 09:17:26
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Line 428 unwary (e.g., floating point addition is
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Line 428 unwary (e.g., floating point addition is
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for the wary. You should not use them unless you know what you are doing |
for the wary. You should not use them unless you know what you are doing |
or you don't care that the results you get are totally bogus. If you |
or you don't care that the results you get are totally bogus. If you |
want to learn about the problems of floating point numbers (and how to |
want to learn about the problems of floating point numbers (and how to |
avoid them), you might start with @cite{David (?) Goldberg, What Every |
avoid them), you might start with @cite{David Goldberg, What Every |
Computer Scientist Should Know About Floating-Point Arithmetic, ACM |
Computer Scientist Should Know About Floating-Point Arithmetic, ACM |
Computing Surveys 23(1):5@minus{}48, March 1991}. |
Computing Surveys 23(1):5@minus{}48, March 1991}. |
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Line 607 The standard guarantees that addresses r
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Line 607 The standard guarantees that addresses r
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are cell-aligned; in addition, gforth guarantees that these addresses |
are cell-aligned; in addition, gforth guarantees that these addresses |
are aligned for all purposes. |
are aligned for all purposes. |
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Note that the standard defines a word @code{char}, which has nothing to |
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do with address arithmetic. |
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doc-chars |
doc-chars |
doc-char+ |
doc-char+ |
doc-cells |
doc-cells |
Line 625 doc-dfloats
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Line 628 doc-dfloats
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doc-dfloat+ |
doc-dfloat+ |
doc-dfalign |
doc-dfalign |
doc-dfaligned |
doc-dfaligned |
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doc-maxalign |
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doc-maxaligned |
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doc-cfalign |
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doc-cfaligned |
doc-address-unit-bits |
doc-address-unit-bits |
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@node Memory block access, , Address arithmetic, Memory access |
@node Memory block access, , Address arithmetic, Memory access |
Line 801 Therefore we recommend avoiding using @c
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Line 808 Therefore we recommend avoiding using @c
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@var{n}. One alternative is @code{@var{n} S+LOOP}, where the negative |
@var{n}. One alternative is @code{@var{n} S+LOOP}, where the negative |
case behaves symmetrical to the positive case: |
case behaves symmetrical to the positive case: |
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@code{-2 0 ?DO i . -1 +LOOP} prints @code{0 -1} |
@code{-2 0 ?DO i . -1 S+LOOP} prints @code{0 -1} |
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@code{-1 0 ?DO i . -1 +LOOP} prints @code{0} |
@code{-1 0 ?DO i . -1 S+LOOP} prints @code{0} |
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@code{ 0 0 ?DO i . -1 +LOOP} prints nothing |
@code{ 0 0 ?DO i . -1 S+LOOP} prints nothing |
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The loop is terminated when the border between @var{limit@minus{}sgn(n)} and |
The loop is terminated when the border between @var{limit@minus{}sgn(n)} and |
@var{limit} is crossed. However, @code{S+LOOP} is not part of the ANS |
@var{limit} is crossed. However, @code{S+LOOP} is not part of the ANS |
Line 878 doc-next
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Line 885 doc-next
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doc-leave |
doc-leave |
doc-?leave |
doc-?leave |
doc-unloop |
doc-unloop |
doc-undo |
doc-done |
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The standard does not allow using @code{cs-pick} and @code{cs-roll} on |
The standard does not allow using @code{cs-pick} and @code{cs-roll} on |
@i{do-sys}. Our system allows it, but it's your job to ensure that for |
@i{do-sys}. Our system allows it, but it's your job to ensure that for |
every @code{?DO} etc. there is exactly one @code{UNLOOP} on any path |
every @code{?DO} etc. there is exactly one @code{UNLOOP} on any path |
through the definition (@code{LOOP} etc. compile an @code{UNLOOP} on the |
through the definition (@code{LOOP} etc. compile an @code{UNLOOP} on the |
fall-through path). Also, you have to ensure that all @code{LEAVE}s are |
fall-through path). Also, you have to ensure that all @code{LEAVE}s are |
resolved (by using one of the loop-ending words or @code{UNDO}). |
resolved (by using one of the loop-ending words or @code{DONE}). |
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Another group of control structure words are |
Another group of control structure words are |
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Line 1038 locals are initialized with values from
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Line 1045 locals are initialized with values from
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Currently there is no way to define locals with user-defined data |
Currently there is no way to define locals with user-defined data |
structures, but we are working on it. |
structures, but we are working on it. |
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GNU Forth allows defining locals everywhere in a colon definition. This poses the following questions: |
GNU Forth allows defining locals everywhere in a colon definition. This |
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poses the following questions: |
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@menu |
@menu |
* Where are locals visible by name?:: |
* Where are locals visible by name?:: |
Line 1312 local0
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Line 1320 local0
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compile the right specialized version, or the general version, as |
compile the right specialized version, or the general version, as |
appropriate: |
appropriate: |
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doc-compile-@@local |
doc-compile-@local |
doc-compile-f@@local |
doc-compile-f@local |
doc-compile-lp+! |
doc-compile-lp+! |
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Combinations of conditional branches and @code{lp+!#} like |
Combinations of conditional branches and @code{lp+!#} like |
Line 1624 GForth comes with @file{gforth.el}, an i
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Line 1632 GForth comes with @file{gforth.el}, an i
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@file{forth.el} by Goran Rydqvist (icluded in the TILE package). The |
@file{forth.el} by Goran Rydqvist (icluded 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-x |}) regions and |
commenting (@kbd{C-x \}) and uncommenting (@kbd{C-u C-x \}) regions and |
removing debugging tracers (@kbd{C-x ~}). I left the stuff I do not use |
removing debugging tracers (@kbd{C-x ~}, @pxref{Debugging}). I left the |
alone, even though some of it only makes sense for TILE. To get a |
stuff I do not use alone, even though some of it only makes sense for |
description of these features, enter Forth mode and type @kbd{C-h m}. |
TILE. To get a description of these features, enter Forth mode and type |
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@kbd{C-h m}. |
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In addition, GForth supports Emacs quite well: The source code locations |
In addition, GForth supports Emacs quite well: The source code locations |
given in error messages, debugging output (from @code{~~}) and failed |
given in error messages, debugging output (from @code{~~}) and failed |