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Groups > comp.lang.forth > #15418

Re: Function Points

From "Rod Pemberton" <do_not_have@notemailnot.cmm>
Newsgroups comp.lang.forth
Subject Re: Function Points
Date 2012-09-03 01:30 -0400
Organization Aioe.org NNTP Server
Message-ID <k21f4p$rc3$1@speranza.aioe.org> (permalink)
References (19 earlier) <k1v3ln$fv2$1@speranza.aioe.org> <7611027.zIGVTbR9Z0@sunwukong.fritz.box> <qrmdnZplrpbVMN7NnZ2dnUVZ_tWdnZ2d@supernews.com> <k20fp6$u0r$1@speranza.aioe.org> <nu2dnWhLvpFEc97NnZ2dnUVZ_gGdnZ2d@supernews.com>

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"Elizabeth D. Rather" <erather@forth.com> wrote in message
news:nu2dnWhLvpFEc97NnZ2dnUVZ_gGdnZ2d@supernews.com...
> On 9/2/12 10:35 AM, Rod Pemberton wrote:
> > "Elizabeth D. Rather" <erather@forth.com> wrote in message
> > news:qrmdnZplrpbVMN7NnZ2dnUVZ_tWdnZ2d@supernews.com...
> > ...
> >
> >> Counted strings are still widely (and appropriately) used as a storage
> >> format, although passing addr/len on the stack is the preferred method.
> >> They are way preferable to null-terminated strings that have to be
> >> counted at run-time!
> >
> > Forth has to count a string at run-time for unknown input too.  That's
> > also typically the only place that counting a string is needed in C at
> > run-time.  The size of static strings in C are known at compile time and
> > dynamic strings require a known size to be allocated at run-time.  Most
> > other uses of strings in C use the entire string.  I.e., strlen() is
> > generally not needed.  Whatever operation is being performed is done
> > until the null character is found or some limit is reached.
>  >
> > BTW, I'm fairly sure I mentioned this to you a while ago, Ms. Rather.
> > :-)
>
> I'm not aware of operations requiring Forth to count strings at
> run-time, since they are normally stored with a count.

At run-time, Forth must generate a count if the string is dynamic.  E.g., if
a string is entered from the keyboard, something counts the string.  In my
interpreter, this should be in the outer or text interpreter.  I'm not sure
where it is for compiled Forth.  (IIRC, this came up at the same time.)

> Doesn't performing an operation "until the null character is found or
> some limit is reached" imply checking every character?

For a simple C implementation, yes, the routine will check every character.
Some methods move or compare using the machine's native wordsize, except for
the start and end of string which are moved or compared as bytes.  Others
take alignment into account too.  Others will code the routines in assembly,
instead of C for speed.  Etc.

> That would preclude using string move instructions on processors
> that have them, wouldn't it?

No.

x86 is the only processor I'm aware of that has string instructions.  It can
move, compare, copy, etc strings of an (8-bit) byte and either 2 bytes
(16-bits) or 4 bytes (32-bits) at a time, depending on processor mode and
special instruction overrides.  The newer x86 processors have 64-bit mode,
although I'm not sure which sizes are supported for that mode.

Although, string instructions are typically precluded since string
instructions are either 1) too specialized for many C compilers to use
effectively or generate, or 2) too slow.  So, many, but not all, C
implementations will implement a loop in C to move or compare one character
at a time.  The processor endianness also affects how code for strings is
coded.  Typically, RISC processors will access 32-bits or larger at a time.
Their byte ordering allows this, whereas x86 can only do that in certain
situations - where the string order isn't important.  I.e., it could be used
for a move, but not for string display.

> Not to mention of cost of the check?

Yes, there would be a check as part of the loop or control-flow.  For x86
string instructions, a check is part of string instructions.


Rod Pemberton

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Thread

Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-21 21:43 -0700
  Re: Comparative Productivity of Programming Languages "A. K." <akk@nospam.org> - 2012-08-22 07:07 +0200
  Re: Comparative Productivity of Programming Languages Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-22 03:35 -0500
    Re: Comparative Productivity of Programming Languages John Passaniti <john.passaniti@gmail.com> - 2012-08-22 14:06 -0700
      Function Points (was: Comparative Productivity of Programming Languages) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-23 14:50 +0000
        Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-23 11:43 -0700
          Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-25 14:13 +0000
            Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 10:12 -0700
              Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-25 15:39 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 15:09 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 12:34 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 16:43 -0700
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-25 18:05 -0700
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-25 20:34 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-26 03:24 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 22:44 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 21:19 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 00:36 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 21:50 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 01:08 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-26 23:20 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 19:33 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-27 13:34 -0500
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-27 22:38 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 02:45 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 18:14 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 18:24 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:22 +0000
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 03:07 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-28 08:18 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 12:15 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-28 23:05 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-29 03:55 -0500
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-27 22:28 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 20:26 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-28 23:17 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 01:13 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 02:23 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 02:59 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 22:18 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 20:44 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-31 01:29 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-31 09:33 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 02:58 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 19:39 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:10 +0000
                Re: Function Points gavino_himself <visploveslisp@gmail.com> - 2012-08-30 20:08 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-30 17:47 -1000
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-27 13:43 -1000
                Re: Function Points "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-08-27 12:14 +0100
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-27 05:12 -0700
                Re: Function Points "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-08-27 15:52 +0100
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-26 13:09 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 20:52 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:08 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-30 10:43 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-30 08:25 -1000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 22:42 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 01:23 -0400
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-31 03:08 -0500
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 18:56 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 02:35 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-31 23:52 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:27 +0000
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:18 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 17:45 +0200
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 16:14 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 19:13 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-09-02 03:19 -0500
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:18 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:04 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 04:02 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 17:40 +0200
                Re: Function Points jim@rainbarrel.com - 2012-09-02 10:32 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 20:49 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:33 -0400
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 17:03 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 09:02 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:35 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 13:42 -1000
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:54 -0700
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-09-03 00:29 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:30 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 21:21 -1000
                Re: Function Points jim@rainbarrel.com - 2012-09-03 10:37 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-04 07:14 +0000
                Re: Function Points Coos Haak <chforth@hccnet.nl> - 2012-09-03 21:12 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 17:32 -0400
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 17:51 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-03 22:37 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-04 04:25 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-04 07:35 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-05 02:13 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-04 20:18 -1000
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-05 10:56 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-05 16:11 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-05 14:07 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:27 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 00:52 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-02 16:28 -0700
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:48 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 20:21 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 14:45 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:12 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 21:26 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:06 -0400
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-31 03:29 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-31 10:35 +0000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 18:49 -0400
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:49 +0000
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-01 08:36 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:11 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 01:58 +0200
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 17:54 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:19 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:05 +0200
                Re: Function Points Coos Haak <chforth@hccnet.nl> - 2012-08-31 23:10 +0200
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-31 15:50 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-01 10:31 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 21:52 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:36 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-01 14:36 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:30 +0200
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 23:15 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-02 15:02 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 01:50 +0200
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:57 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-03 23:11 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-04 14:30 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-04 10:14 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-04 22:10 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 00:19 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-06 17:48 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 12:01 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-06 22:02 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 14:19 -0700
                Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-07 11:30 +0000
                Re: Heap (was: Function Points) Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-07 18:12 +0200
                Re: Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-07 16:48 +0000
                Re: Heap (was: Function Points) Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-07 21:34 +0200
                Re: Heap Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-09-07 22:04 +0100
                Re: Heap anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-08 11:52 +0000
                Re: Heap Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-08 22:48 +0200
                Re: Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-08 12:11 +0000
                priority queue (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-03 11:46 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 15:03 +0200
                Re: Function Points mhx@iae.nl (Marcel Hendrix) - 2012-09-03 22:36 +0200
                Re: Function Points mhx@iae.nl (Marcel Hendrix) - 2012-09-06 20:27 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-09-02 04:00 -0500
                Re: Function Points visualforth@rocketmail.com - 2012-09-03 10:40 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 20:26 +0200
                Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-27 11:49 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 09:16 -0700
                Re: Function Points Josh Grams <josh@qualdan.com> - 2012-08-28 22:46 +0000
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-28 16:06 -0700
                Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-28 20:50 -0400
              Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-26 12:59 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 22:24 -0700
        Re: Function Points (was: Comparative Productivity of Programming Languages) John Passaniti <john.passaniti@gmail.com> - 2012-08-23 15:02 -0700
          Re: Function Points (was: Comparative Productivity of Programming Languages) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-25 14:57 +0000
  Re: Comparative Productivity of Programming Languages "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-22 08:07 -0400
    Re: Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-22 08:12 -0700
  Re: Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-22 07:37 -0700

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