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Groups > comp.lang.forth > #42031
| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: old `leave` renamed to `exhaust` |
| Date | 2015-09-16 06:10 +0000 |
| Organization | Institut fuer Computersprachen, Technische Universitaet Wien |
| Message-ID | <2015Sep16.081024@mips.complang.tuwien.ac.at> (permalink) |
| References | (2 earlier) <mt5b3m$2c9$1@speranza.aioe.org> <2015Sep14.103356@mips.complang.tuwien.ac.at> <mt8f9i$qm3$1@speranza.aioe.org> <y7pior0acvxj.ch2dlom72stl$.dlg@40tude.net> <mtafsr$j8m$1@speranza.aioe.org> |
"HAA" <someone@microsoft.com> writes:
>Coos Haak wrote:
>>
>> Is there any description of what /LOOP and \LOOP are supposed to do?
>> I've never found an implementation of them, even several versions
>> of Gforth don't have them.
>
>/LOOP \LOOP use unsigned limit/index and are defined in the Forth-79
>Reference Word Set.
Thanks. This says:
/LOOP n -- "up-loop"
A DO-LOOP terminating word. The loop index is incremented by
the unsigned magnitude of n. Until the resultant index
exceeds the limit, execution returns to just after the
corresponding DO: otherwise, the index and limit are
discarded. Magnitude logic is used.
\LOOP n -- I,C "down-loop"
A DO-LOOP terminating word. The loop index is decremented by
n and the loop terminated when the resultant index becomes
equal to or less than the limit. Magnitude logic is used, and
n must be positive.
Not sure what they meant by "magnitude logic"; "magnitude" occurs only
in U< /LOOP and \LOOP in the Forth-79 document, with no definition.
\LOOP works like Gforth's -LOOP, except that -LOOP also works for
unsigned operands exceeding the +n range. The "exceeds the limit" in
/LOOP is curious, as it does not match \LOOP and LOOP either in
wording, or in meaning.
+LOOP in Forth-79 already was assymetric:
+LOOP n -- I,C,141 "plus-loop"
Add the signed increment n to the loop index using the
convention for +, and compare the total to the limit. Return
execution to the corresponding DO until the new index is equal
to or greater than the limit (n>0), or until the new index is
less than the limit (n<0). Upon the exiting from the loop,
discard the loop control parameters, continuing execution
ahead. Index and limit are signed integers in the range
{-32,768..32,767}.
(Comment: It is a historical precedent that the limit for n<0
is irregular. Further consideration of the characteristic is
unlikely.)
- anton
--
M. Anton Ertl http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
New standard: http://www.forth200x.org/forth200x.html
EuroForth 2015: http://www.rigwit.co.uk/EuroForth2015/
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old `leave` renamed to `exhaust` Marcos Cruz <null_email_so_use_my_contact_page@programandala.net> - 2015-09-07 20:29 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-08 14:52 +1000
Re: old `leave` renamed to `exhaust` Mark Wills <markwills1970@gmail.com> - 2015-09-08 00:57 -0700
Re: old `leave` renamed to `exhaust` Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-08 15:19 +0200
Re: old `leave` renamed to `exhaust` Marcos Cruz <null_email_so_use_my_contact_page@programandala.net> - 2015-09-08 16:25 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-09 11:39 +1000
Re: old `leave` renamed to `exhaust` Marcos Cruz <null_email_so_use_my_contact_page@programandala.net> - 2015-09-09 10:42 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-10 14:05 +1000
Re: old `leave` renamed to `exhaust` Marcos Cruz <null_email_so_use_my_contact_page@programandala.net> - 2015-09-10 13:33 +0000
Re: old `leave` renamed to `exhaust` Coos Haak <chforth@hccnet.nl> - 2015-09-10 22:04 +0200
Re: old `leave` renamed to `exhaust` Coos Haak <chforth@hccnet.nl> - 2015-09-10 22:13 +0200
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-11 13:14 +1000
Re: old `leave` renamed to `exhaust` Coos Haak <chforth@hccnet.nl> - 2015-09-11 12:30 +0200
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-11 21:47 +1000
Re: old `leave` renamed to `exhaust` Bernd Paysan <bernd.paysan@gmx.de> - 2015-09-11 14:09 +0200
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-12 11:29 +1000
Re: old `leave` renamed to `exhaust` "Elizabeth D. Rather" <erather@forth.com> - 2015-09-11 16:05 -1000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-14 12:25 +1000
Re: old `leave` renamed to `exhaust` "Elizabeth D. Rather" <erather@forth.com> - 2015-09-13 17:53 -1000
Re: old `leave` renamed to `exhaust` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-14 08:33 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-15 16:55 +1000
Re: old `leave` renamed to `exhaust` hughaguilar96@gmail.com - 2015-09-15 01:46 -0700
Re: old `leave` renamed to `exhaust` Coos Haak <chforth@hccnet.nl> - 2015-09-15 15:14 +0200
Re: old `leave` renamed to `exhaust` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-15 15:13 +0000
Re: old `leave` renamed to `exhaust` hughaguilar96@gmail.com - 2015-09-15 16:13 -0700
Re: old `leave` renamed to `exhaust` jim.brakefield@ieee.org - 2015-09-15 17:05 -0700
Re: old `leave` renamed to `exhaust` hughaguilar96@gmail.com - 2015-09-15 18:35 -0700
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-19 11:42 +1000
Re: old `leave` renamed to `exhaust` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-19 10:48 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-20 00:01 +1000
Re: old `leave` renamed to `exhaust` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-19 15:02 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-21 15:51 +1000
Re: old `leave` renamed to `exhaust` "Elizabeth D. Rather" <erather@forth.com> - 2015-09-15 08:45 -1000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-16 11:18 +1000
Re: old `leave` renamed to `exhaust` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-16 06:10 +0000
Re: old `leave` renamed to `exhaust` "HAA" <someone@microsoft.com> - 2015-09-17 15:15 +1000
Re: old `leave` renamed to `exhaust` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-09-17 06:04 +0000
Re: old `leave` renamed to `exhaust` Coos Haak <chforth@hccnet.nl> - 2015-09-11 14:16 +0200
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