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Groups > comp.lang.forth > #42958
| From | anton@mips.complang.tuwien.ac.at (Anton Ertl) |
|---|---|
| Newsgroups | comp.lang.forth |
| Subject | Re: Preserving standard and common use names (Re: alternatives to `find`) |
| Date | 2015-10-29 10:00 +0000 |
| Organization | Institut fuer Computersprachen, Technische Universitaet Wien |
| Message-ID | <2015Oct29.110043@mips.complang.tuwien.ac.at> (permalink) |
| References | (5 earlier) <46986dbe-0807-4e88-a8d5-c69ed9ef4a84@googlegroups.com> <2015Oct27.180941@mips.complang.tuwien.ac.at> <5630c0b8.248998702@news.eternal-september.org> <n0r81b$ncv$1@dont-email.me> <563154cd.286908193@news.eternal-september.org> |
stephen@mpeforth.com (Stephen Pelc) writes:
>From a software writer's point of
>view, a separate FP stack wins every time for ease of use.
...
>However, you totally ignore my main point, which is that sometimes
>standards just get it wrong. In such cases we should just admit it and
>change the standard.
Yes, Forth-94 got it wrong for the floating-point stack issue, and we
admitted it and changed it in Forth-2012. And as a consequence,
programmers can now more easily write standard programs (without
environmental dependencies), and these programs run faster than
Forth-94 programs for the same task. Just to remind you:
| Forth-2012 Forth-94
|500x500 mm - normal algorithm 0.570s 0.727s
|500x500 mm - transposed B matrix 0.550s 0.686s
|500x500 mm - Robert's algorithm 0.547s 0.684s
> If I knew then what I know about 32 bit CPUs and
>and 32 bit FP, I would not have accepted the combined/separate FP
>stack argument without a *lot* more consideration.
Your claim was that the Cortex-M4F uses the integer registers as FP
registers, and that's why you see a combined stack as better, but
looking at the Cortex-M4 Technical Reference Manual
<http://infocenter.arm.com/help/topic/com.arm.doc.ddi0439b/DDI0439B_cortex_m4_r0p0_trm.pdf>,
it has a separate set of 32 single-precision FP registers and uses the
32-bit subset of the usual ARM VFP floating-point instruction set, and
I just tried to assemble a floating-point instruction using integer
registers, and the assembler told me:
Error: VFP single precision register expected -- `fadds r0,r0,r1'
So the Cortex-M4, too, is among the CPUs that have separate FP
registers.
So if you have a shared stack and cache the TOS in an integer register
(which is the VFX calling convention for IA-32), and you want to do an
FP operation involving that stack item, you need an extra VMOV
instruction for moving that stack item into an FP register, costing
performance; conversely, if the TOS at the end of a definition comes
out of an FP instruction, you need to move it from the FP register to
the TOS integer register.
By contrast, with a separate FP stack, you can keep the FTOS in an FP
register, and don't need to use VMOV instructions to move between
integer and FP registers. Yes, you need a separate FP stack pointer
(unless you take the PAF way for the parts of the program that comply
with PAF restrictions), but that's the same as on other CPUs, where
you also have separate FP registers and where a separate FP stack
needs a separate stack pointer, such as IA-32 and AMD64. And where the
Forth-2012 way is faster than the Forth-94 way, as shown above.
>People have already made a similar point to me about the byte
>addressed CPU assumption and 1 CHARS = 1. More thought needed.
There Forth-94 also got it wrong, but at looked like the way to go in
the early 1990s (in contrast to the Forth-94 FP stack non-decision,
which was always a bad idea). In the meantime we have seen that 1
CHARS >1 is not needed. Sure some people may need more thought, but
will they actually take more thought? Two of the three people who
abstained had not been present when the proposal was presented and
discussed the day before, and probably had not read the proposal
earlier. So of course they felt they were not sufficiently qualified
to decide on the proposal, and abstained (probably without knowing
that too many abstentions are also not a consensus).
- 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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alternatives to `find` Marcos Cruz <use_the_contact_page@programandala.net> - 2015-10-21 20:09 +0000
Re: alternatives to `find` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-22 05:54 +0000
Re: alternatives to `find` Marcos Cruz <use_the_contact_page@programandala.net> - 2015-10-22 15:37 +0000
Re: alternatives to `find` Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-22 22:03 -0700
Re: alternatives to `find` Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-22 22:14 -0700
Re: alternatives to `find` hughaguilar96@gmail.com - 2015-10-23 01:28 -0700
Re: alternatives to `find` Marcos Cruz <use_the_contact_page@programandala.net> - 2015-10-23 12:12 +0000
Re: alternatives to `find` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-26 11:39 +0000
Re: alternatives to `find` Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-26 05:14 -0700
Re: alternatives to `find` Marcos Cruz <use_the_contact_page@programandala.net> - 2015-10-23 12:30 +0000
Re: alternatives to `find` Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-23 22:52 -0700
Re: alternatives to `find` Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-23 23:14 -0700
Re: alternatives to `find` Marcos Cruz <use_the_contact_page@programandala.net> - 2015-10-24 11:15 +0000
Re: alternatives to `find` Coos Haak <chforth@hccnet.nl> - 2015-10-24 14:34 +0200
Re: alternatives to `find` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-24 14:45 +0000
Re: alternatives to `find` Coos Haak <chforth@hccnet.nl> - 2015-10-24 17:23 +0200
Preserving standard and common use names (Re: alternatives to `find`) Marcos Cruz <use_the_contact_page@programandala.net> - 2015-10-24 11:53 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-24 22:48 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) "Elizabeth D. Rather" <erather@forth.com> - 2015-10-24 21:05 -1000
Re: Preserving standard and common use names (Re: alternatives to `find`) Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-10-25 01:34 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) "Elizabeth D. Rather" <erather@forth.com> - 2015-10-24 22:45 -1000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-25 09:16 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) "Elizabeth D. Rather" <erather@forth.com> - 2015-10-25 08:46 -1000
Re: Preserving standard and common use names (Re: alternatives to `find`) hughaguilar96@gmail.com - 2015-10-25 21:31 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-25 18:50 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-10-26 01:57 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Paul Rubin <no.email@nospam.invalid> - 2015-10-26 02:07 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Ron Aaron <rambamist@gmail.com> - 2015-10-26 11:14 +0200
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-10-26 04:18 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) "Elizabeth D. Rather" <erather@forth.com> - 2015-10-26 09:22 -1000
Re: Preserving standard and common use names (Re: alternatives to `find`) hughaguilar96@gmail.com - 2015-10-26 21:34 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-26 10:58 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-10-26 05:59 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-26 14:58 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-27 17:09 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-28 12:50 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-28 15:56 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Paul Rubin <no.email@nospam.invalid> - 2015-10-28 10:31 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-28 19:26 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) Paul Rubin <no.email@nospam.invalid> - 2015-10-28 12:37 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-28 23:03 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Paul Rubin <no.email@nospam.invalid> - 2015-10-28 16:21 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-28 20:37 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-28 23:13 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-29 03:01 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-29 10:04 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-29 15:29 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-10-30 04:17 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-10-30 11:36 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-31 15:25 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-10-31 20:34 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-10-30 20:51 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-11-02 01:39 -0800
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-02 11:12 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-11-02 12:09 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-11-02 05:09 -0800
Re: Preserving standard and common use names (Re: alternatives to `find`) Raimond Dragomir <raimond.dragomir@gmail.com> - 2015-11-02 06:23 -0800
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-02 14:39 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2015-11-20 16:20 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Mark Wills <markwills1970@gmail.com> - 2015-11-21 00:26 -0800
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-31 15:03 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-31 16:35 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-01 14:07 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-11-01 21:05 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-31 16:31 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-31 20:33 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) Bernd Paysan <bernd.paysan@gmx.de> - 2015-10-29 22:27 +0100
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-29 13:19 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-29 10:00 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-29 13:29 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-29 14:04 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-29 16:29 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-29 16:42 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-29 16:13 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) mhx@iae.nl - 2015-10-29 12:19 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-31 14:12 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) stephen@mpeforth.com (Stephen Pelc) - 2015-10-31 16:49 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) Paul Rubin <no.email@nospam.invalid> - 2015-10-31 10:33 -0700
Re: Preserving standard and common use names (Re: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-01 14:14 +0000
Re: Preserving standard and common use names (Re: alternatives to `find`) hughaguilar96@gmail.com - 2015-10-25 21:52 -0700
Re: alternatives to `find` Albert van der Horst <albert@spenarnc.xs4all.nl> - 2015-10-30 12:30 +0000
Re: alternatives to `find` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-10-26 11:47 +0000
Re: alternatives to `find` Chris Curl <ccurl609@gmail.com> - 2015-11-02 06:17 -0800
Re: alternatives to `find` Mark Wills <markwills1970@gmail.com> - 2015-11-02 06:35 -0800
Re: alternatives to `find` Coos Haak <chforth@hccnet.nl> - 2015-11-02 15:45 +0100
Re: alternatives to `find` Chris Curl <ccurl609@gmail.com> - 2015-11-02 07:17 -0800
Re: alternatives to `find` Albert van der Horst <albert@spenarnc.xs4all.nl> - 2015-11-02 19:39 +0000
Re: alternatives to `find` Mark Wills <markwills1970@gmail.com> - 2015-11-02 12:19 -0800
Re: alternatives to `find` anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-03 11:31 +0000
Re: alternatives to `find` Albert van der Horst <albert@spenarnc.xs4all.nl> - 2015-11-03 21:11 +0000
MOVE and CMOVE speed (was: alternatives to `find`) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-11-04 09:52 +0000
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