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Groups > comp.lang.forth > #59365
| From | Alex <alex@rivadpm.com> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: Would ?EXIT work in all ANS-Forth systems? |
| Date | 2017-05-16 12:35 +0100 |
| Organization | A noiseless patient Spider |
| Message-ID | <ofeo0k$c56$1@dont-email.me> (permalink) |
| References | (9 earlier) <86inl266tx.fsf@molnjunk.nocrew.org> <ofdgrt$6cd$1@gioia.aioe.org> <ofedqi$a3s$1@dont-email.me> <ofeegl$c7g$1@dont-email.me> <d5GdnW8mjMeYUYfEnZ2dnUU7-c3NnZ2d@supernews.com> |
On 5/16/2017 10:53, Andrew Haley wrote:
> Alex <alex@rivadpm.com> wrote:
>> On 5/16/2017 09:42, Gerry Jackson wrote:
>>>
>>> So they didn't forget about [return stack trickery], they chose to
>>> make it non-standard.
>>
>> And gave us CATCH and THROW, a much better & portable solution that
>> allows you to mark a place and return to it without any return stack
>> dependencies. Why more don't use it is a little mystifying.
>
> Forth's CATCH/THROW is the lightest-weight exception-handling
> mechanism that I've seen, but it's still heavier than EXIT, which is
The lightest weight AFAIK uses quite a different formulation to
CATCH/THROW.
Saving the stack pointers with CATCH has an overhead, and it's a good
bit slower than a straightforward EXECUTE. If you are continually
CATCHing and not THROWing, then the overhead might get to be significant.
The alternative is to map out error handlers by address range and have a
TRY section. There's no CATCH overhead, as the code covered by the TRY
range is mapped at compile time. Just EXECUTE inside your CATCH range
and be damned; and if you are damned and THROW, then have the THROW code
take the hit searching through the call stack into the pre-built address
range table to find the appropriate TRY handler. (That search presumes
some sort of order to the stack; either all return addresses or stack
frames, which is very un-Forthish. Good for C though. Windows 64 bit
uses a variation of this technique.)
But as a dynamic mechanism. CATCH/THROW takes some beating. Here's an
STC x86 based MARK and UNWIND, which is even lighter weight than CATCH
and THROW. (EAX is top of stack, the data stack is EBP.) Setup & exit on
CATCH is 3 extra instructions (PUSH MOV POP ) (even EXECUTE has to drop
the XT) and a THROW is 2 (MOV POP).
variable handler
code mark ( xt -- )
mov ecx eax ( save xt )
mov eax { ebp } ( drop xt )
add ebp cell
push { handler } \ handler @ >r
mov { handler } esp \ rp @ handler !
call ecx \ execute
pop { handler } \ r> handler !
ret
end-code
code unwind ( -- )
mov esp { handler } \ handler @ rp!
pop { handler } \ r> handler !
ret
end-code
> (almost) the lightest-weight subroutine return mechanism I've ever > seen. Having siad that, it's difficult for an analytical Forth
> compiler to optimize CATCH and THROW: I don't know if any of them
> attempt it.
For a handful of instructions, the considerable compile-time effort
isn't probably worth it. Just don't do it inside a loop.
--
Alex
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Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-10 08:21 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-10 16:39 +0100
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-10 08:46 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-10 16:04 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-11 04:22 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-11 10:35 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-11 05:08 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-11 03:51 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-11 07:02 -0500
Re: Would ?EXIT work in all ANS-Forth systems? rickman <gnuarm@gmail.com> - 2017-05-13 11:55 -0400
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 09:32 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-15 11:56 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 12:20 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-15 12:31 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 15:50 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-10 16:49 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-10 12:04 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-11 01:08 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-11 09:13 +0100
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-11 01:48 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-11 09:59 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-12 14:20 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-12 17:01 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-12 22:18 -0700
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-13 03:09 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-13 21:07 +1000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-13 14:20 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-14 11:59 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-14 09:21 -0500
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-14 10:43 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-14 18:35 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-05-15 07:11 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 04:35 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-15 03:54 -0700
Re: Would ?EXIT work in all ANS-Forth systems? mhx@iae.nl - 2017-05-15 04:07 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 06:23 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-15 06:53 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 09:18 -0500
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-14 22:44 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-15 04:16 -0500
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-16 02:00 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-16 02:43 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 05:08 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 12:11 +0000
Re: Would ?EXIT work in all ANS-Forth systems? NN <november.nihal@gmail.com> - 2017-05-17 05:24 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-17 07:35 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-17 14:59 +0100
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-17 13:30 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-15 11:09 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-14 21:17 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-05-15 07:13 +0200
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-16 10:24 +1000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-16 01:13 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 12:26 +0000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-17 01:58 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-17 16:45 +0000
Re: Would ?EXIT work in all ANS-Forth systems? obi65537@gmail.com - 2017-05-25 12:04 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-26 10:02 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-26 07:46 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-26 13:53 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-26 10:14 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-26 10:16 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 08:59 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-26 11:27 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 10:19 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Lars Brinkhoff <lars.spam@nocrew.org> - 2017-05-26 20:20 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 21:38 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Cecil Bayona <cbayona@cbayona.com> - 2017-05-26 14:06 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-26 22:00 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-26 17:06 +0000
Re: Would ?EXIT work in all ANS-Forth systems? hum9 <obi65537@gmail.com> - 2017-05-27 01:15 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-28 14:17 +0000
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-27 17:40 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-24 15:46 +1000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <obi65537@gmail.com> - 2017-05-25 11:51 -0700
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <obi65537@gmail.com> - 2017-05-25 20:38 -0700
Re: Would ?EXIT work in all ANS-Forth systems? obi65537@gmail.com - 2017-05-25 22:03 -0700
Re: Would ?EXIT work in all ANS-Forth systems? obi65537@gmail.com - 2017-05-25 22:09 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-26 21:56 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-26 13:30 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-27 15:04 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-27 17:33 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-29 12:17 +1000
Re: Would ?EXIT work in all ANS-Forth systems? hum9 <obi65537@gmail.com> - 2017-05-27 00:33 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-27 14:53 +1000
READ-FILE over-specified? "HAA" <someone@microsoft.com> - 2017-05-27 21:28 +1000
Re: READ-FILE over-specified? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-27 13:11 +0000
Re: READ-FILE over-specified? "HAA" <someone@microsoft.com> - 2017-05-29 13:47 +1000
Re: READ-FILE over-specified? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-28 09:44 +0200
Re: READ-FILE over-specified? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-28 13:41 +0000
Re: READ-FILE over-specified? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-28 19:59 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2017-05-16 09:42 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 09:53 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 04:53 -0500
Re: Would ?EXIT work in all ANS-Forth systems? albert@cherry.spenarnc.xs4all.nl (Albert van der Horst) - 2017-05-16 12:32 +0200
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 12:35 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 10:48 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 18:23 +0100
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-17 04:33 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-17 12:29 +0100
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 10:28 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 10:43 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 16:34 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-16 12:41 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-17 16:14 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 03:05 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-18 16:33 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 12:43 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 04:01 -0500
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-18 15:41 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Andrew Haley <andrew29@littlepinkcloud.invalid> - 2017-05-18 11:58 -0500
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-18 22:57 +0100
Re: Would ?EXIT work in all ANS-Forth systems? "HAA" <someone@microsoft.com> - 2017-05-17 00:32 +1000
Re: Would ?EXIT work in all ANS-Forth systems? Alex <alex@rivadpm.com> - 2017-05-16 15:53 +0100
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-15 05:29 +0000
Re: Would ?EXIT work in all ANS-Forth systems? humptydumpty <ouatubi@gmail.com> - 2017-05-14 23:00 -0700
Re: Would ?EXIT work in all ANS-Forth systems? rickman <gnuarm@gmail.com> - 2017-05-17 12:27 -0400
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 09:16 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 09:55 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-13 14:25 +0000
Re: Would ?EXIT work in all ANS-Forth systems? Julian Fondren <julian.fondren@gmail.com> - 2017-05-13 07:49 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 09:59 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-15 12:22 +0000
Re: Would ?EXIT work in all ANS-Forth systems? "Rudy Velthuis" <newsgroups@rvelthuis.de> - 2017-05-13 14:19 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-14 23:23 -0700
Re: Would ?EXIT work in all ANS-Forth systems? Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-15 00:10 -0700
Re: Would ?EXIT work in all ANS-Forth systems? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-15 09:35 +0000
Re: Would ?EXIT work in all ANS-Forth systems? lehs <skydda.barnen@gmail.com> - 2017-05-15 00:54 -0700
Return-address manipulation (was: Would ?EXIT ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-15 08:47 +0000
Re: Return-address manipulation (was: Would ?EXIT ...) stephen@mpeforth.com (Stephen Pelc) - 2017-05-15 11:53 +0000
Re: Return-address manipulation (was: Would ?EXIT ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2017-05-16 13:03 +0000
Re: Return-address manipulation (was: Would ?EXIT ...) Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-16 07:06 -0700
Re: Return-address manipulation (was: Would ?EXIT ...) Raimond Dragomir <raimond.dragomir@gmail.com> - 2017-05-16 07:14 -0700
Re: Would ?EXIT work in all ANS-Forth systems? "Elizabeth D. Rather" <erather@forth.com> - 2017-05-14 21:58 -1000
Re: Would ?EXIT work in all ANS-Forth systems? stephen@mpeforth.com (Stephen Pelc) - 2017-05-15 11:23 +0000
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