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Groups > comp.lang.forth > #33737
| From | Bernd Paysan <bernd.paysan@gmx.de> |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: uninitialized and implicitly initialized locals (was: More ranting) |
| Date | 2014-10-07 22:15 +0200 |
| Organization | 1&1 Internet AG |
| Message-ID | <m11hla$ffe$1@online.de> (permalink) |
| References | (1 earlier) <45d05d06-5acf-4792-96cd-ab32e411a18b@googlegroups.com> <8b0123d6-4076-4dce-a0eb-c6163148bf30@googlegroups.com> <qsidnSWZzPB2Na7JnZ2dnUU7-YudnZ2d@supernews.com> <5433dfd9$0$6905$e4fe514c@dreader36.news.xs4all.nl> <2014Oct7.173637@mips.complang.tuwien.ac.at> |
Anton Ertl wrote:
> Hmm, given that he still implements all locals on the in-memory return
> stack, it should not be that hard to extend his implementation to
> accept something close to the Gforth-supported usage, with one
> restriction still remaining: The first locals definition must happen
> outside any control structure. When you see another locals
> definition, you backpatch the return-stack reservation produced by the
> first locals definition to increase the number of reserved locals, and
> store the newly defined locals in the new slots.
I don't see any need for this sort of restriction; the only problem of using
the return stack for locals is when your code contains >r and r>, and
declares the locals in between.
So let's see how VFX does cope with that today:
: test >r { a b } a b + r> . . ; ok
1 2 3 test 134520832 3
CS=0023 DS=002B ES=002B SS=002B FS=0000 GS=0063
EAX=0000:0001 EBX=091A:F000 ECX=091A:EF78 EDX=0000:0001
ESI=091C:0000 EDI=080B:F345 EBP=091B:EFC4 ESP=091A:EFB0
EIP=0000:0003 EFLAGS=0001:0207
--- RS top ---
Oops. So I would declare that possible problem a non-issue, because it
doesn't work right now, either, and it fails, because declaring locals
pushes a "clean up the locals" address on the return stack.
If your >r and r> are balanced without declaring new locals in between (and
VFX can handle that quite well), you can just allocate locals on the return
stack using exactly the same algorithm we use in Gforth to allocate locals
on the locals stack.
> He would also need to implement the scoping of locals, and that can
> also be done in a single pass (and is done so by Gforth), but my guess
> is that he did not like the define-locals-where-needed approach
> because of code generation issues.
Actually, with an analytical compiler, locals could be implemented "right",
i.e. it is just a virtual register, assigned to a value on the stack, given
a place on a virtual locals stack (which may actually live on the return
stack, but allocation of the maximum space needed in a word is moved to the
beginning, and deallocation is attached to every compiled EXIT) to be saved
when the register allocater runs out of registers (or needs to caller-save
registers when calling other words), and that's it - only those locals which
need saving in between need to be allocated on that stack, all locals that
can be kept in registers and are dead before they need saving don't. That's
what an analytical compiler is for, to take the whole word, and analyze the
total dataflow within. The sequence above { a b } a b + should compile to
the same code as a simple +.
It's just that in VFX, locals are second class to the optimizer, because
they don't happen enough to be worth the effort. That's a tradeoff
decision, MPE can't do everything.
BTW, that's what iForth 4.06 (64 bit Linux version, the last trial version I
have) does on the code above (properly Marcelified):
FORTH> : test >r params| a b | a b + r> . . ; ok
FORTH> 1 2 3 test 3 3 ok
So others have done some more effort ;-). The code it generates doesn't
fully convince me, but it is at least doing what you might expect.
--
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/
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Re: Why smudge? hughaguilar96@yahoo.com - 2014-09-30 19:25 -0700
Re: Why smudge? november.nihal@gmail.com - 2014-10-01 08:54 -0700
Re: Why smudge? albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-01 19:09 +0000
Re: Why smudge? november.nihal@gmail.com - 2014-10-01 10:16 -0700
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-01 18:54 -0700
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-02 15:31 -0700
Re: Why smudge? Michael Barry <barrym95838@yahoo.com> - 2014-10-02 16:35 -0700
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-02 17:02 -0700
Re: Why smudge? Michael Barry <barrym95838@yahoo.com> - 2014-10-02 17:51 -0700
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-02 18:50 -0700
Re: Why smudge? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-04 00:30 +0100
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-03 17:40 -0700
Re: Why smudge? Raimond Dragomir <raimond.dragomir@gmail.com> - 2014-10-03 23:00 -0700
Pelc's effort to sabotage cross-compiler writing has a work-around now! hughaguilar96@yahoo.com - 2014-10-04 21:14 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-05 03:42 -0500
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! Enoch <emc.consultants@gmail.com> - 2014-10-05 10:43 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! hughaguilar96@yahoo.com - 2014-10-05 20:21 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-06 03:58 -0500
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! hughaguilar96@yahoo.com - 2014-10-05 17:09 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! Michael Barry <barrym95838@yahoo.com> - 2014-10-06 11:15 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! hughaguilar96@yahoo.com - 2014-10-06 18:52 -0700
More ranting Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-07 03:48 -0500
Re: More ranting albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-07 12:43 +0000
Re: More ranting Bernd Paysan <bernd.paysan@gmx.de> - 2014-10-07 16:23 +0200
Re: More ranting "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-16 01:03 -0400
Re: More ranting Just Ian <superian@gmail.com> - 2014-10-16 07:14 -0700
Re: More ranting Michael Barry <barrym95838@yahoo.com> - 2014-10-16 13:23 -0700
uninitialized and implicitly initialized locals (was: More ranting) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-07 15:36 +0000
Re: uninitialized and implicitly initialized locals (was: More ranting) Bernd Paysan <bernd.paysan@gmx.de> - 2014-10-07 22:15 +0200
Re: uninitialized and implicitly initialized locals (was: More ranting) mhx@iae.nl - 2014-10-07 15:07 -0700
Re: uninitialized and implicitly initialized locals (was: More ranting) Bernd Paysan <bernd.paysan@gmx.de> - 2014-10-08 03:11 +0200
Re: uninitialized and implicitly initialized locals (was: More ranting) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-08 13:25 +0000
Re: uninitialized and implicitly initialized locals (was: More ranting) hughaguilar96@yahoo.com - 2014-10-09 16:22 -0700
Re: uninitialized and implicitly initialized locals (was: More ranting) "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-17 21:58 -0400
Re: uninitialized and implicitly initialized locals (was: More ranting) mhx@iae.nl (Marcel Hendrix) - 2014-10-12 11:18 +0200
Re: uninitialized and implicitly initialized locals (was: More ranting) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-08 12:35 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-07 15:27 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-08 12:56 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-08 08:24 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-08 15:32 +0000
Simplified automatic scoping (was: uninitialized ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-08 16:06 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-08 11:57 -0500
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-08 12:18 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-09 14:19 +0000
Re: uninitialized and implicitly initialized locals hughaguilar96@yahoo.com - 2014-10-09 14:42 -0700
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-09 14:07 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-09 10:44 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-10 16:03 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-10 13:35 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-11 10:53 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-12 11:34 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-15 12:44 +0000
Re: uninitialized and implicitly initialized locals albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-15 14:34 +0000
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-15 15:03 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-15 11:10 -0500
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-16 12:19 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-17 03:56 -0500
Re: uninitialized and implicitly initialized locals "Elizabeth D. Rather" <erather@forth.com> - 2014-10-17 07:48 -1000
Re: uninitialized and implicitly initialized locals hughaguilar96@yahoo.com - 2014-10-17 19:26 -0700
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-18 12:55 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-18 13:21 -0500
Re: uninitialized and implicitly initialized locals "Elizabeth D. Rather" <erather@forth.com> - 2014-10-18 08:44 -1000
Re: uninitialized and implicitly initialized locals albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-19 09:53 +0000
Re: uninitialized and implicitly initialized locals anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2014-10-20 12:48 +0000
Re: uninitialized and implicitly initialized locals "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-20 16:24 -0400
Re: uninitialized and implicitly initialized locals "Elizabeth D. Rather" <erather@forth.com> - 2014-10-20 10:30 -1000
Re: uninitialized and implicitly initialized locals hughaguilar96@yahoo.com - 2014-10-20 16:23 -0700
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-26 04:16 -0500
Re: uninitialized and implicitly initialized locals mhx@iae.nl (Marcel Hendrix) - 2014-10-26 11:32 +0200
Re: uninitialized and implicitly initialized locals stephenXXX@mpeforth.com (Stephen Pelc) - 2014-10-26 14:27 +0000
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-26 13:56 -0500
Re: uninitialized and implicitly initialized locals mhx@iae.nl (Marcel Hendrix) - 2014-10-26 20:32 +0200
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-26 16:18 -0500
Re: uninitialized and implicitly initialized locals hughaguilar96@yahoo.com - 2014-10-26 15:05 -0700
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-26 17:53 -0500
Re: uninitialized and implicitly initialized locals hughaguilar96@yahoo.com - 2014-10-26 16:30 -0700
Re: uninitialized and implicitly initialized locals "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-27 01:45 -0400
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-27 12:21 -0500
Re: uninitialized and implicitly initialized locals Andrew Haley <andrew29@littlepinkcloud.invalid> - 2014-10-26 17:57 -0500
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-06 20:55 +0100
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! hughaguilar96@yahoo.com - 2014-10-06 16:05 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-09 07:36 +0100
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! stephenXXX@mpeforth.com (Stephen Pelc) - 2014-10-10 01:52 +0000
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! hughaguilar96@yahoo.com - 2014-10-09 19:56 -0700
Re: Pelc's effort to sabotage cross-compiler writing has a work-around now! "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-17 23:11 -0400
Re: Why smudge? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-05 11:05 +0100
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-05 19:48 -0700
Re: Why smudge? Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2014-10-06 07:53 +0100
Re: Why smudge? "Elizabeth D. Rather" <erather@forth.com> - 2014-10-05 21:29 -1000
Re: Why smudge? hughaguilar96@yahoo.com - 2014-10-09 15:16 -0700
Re: Why smudge? "Rod Pemberton" <buzzoff@nonamewhichexists.cmm> - 2014-10-16 01:03 -0400
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