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Re: Comparing addresses

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Andrew Haley <andrew29@littlepinkcloud.invalid> writes:
>Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:
>> 3.1.1 says:
>> 
>> | a-addr => c-addr => addr => u;
>> 
>> I.e., addr is a subtype of u.  Therefore I consider programs that
>> compare addresses with U< standard-compliant.
>
>How does that follow?

6.1.2340 U< ( u1 u2 -- flag )

Also:

|A.3.1.3.3 Addresses
|
|An address is uniquely represented as a single cell unsigned number
|and can be treated as such when being moved to, from, or upon the
|stack. Conversely, each unsigned number represents a unique address
|(which is not necessarily an address of accessible memory). This
|one-to-one relationship between addresses and unsigned numbers forces
|an equivalence between address arithmetic and the corresponding
|operations on unsigned numbers.

>> And if you implement Forth on hardware that has system stuff around
>> MAX-N and where the user RAM can straddle 0, it's your job to make
>> sure that contiguous regions don't straddle 0.
>
>And that.  I don't quite see how a subtype relationship implies
>ordering.  For example, every address between FFF0 ... 0010 is of type
>u.

Ordering is defined for u (through U< and U>), and therefore for addr.

You seem to argue that each address has to be considered on its own,
but the addresses in a contiguous region are contiguous.

Sure, one can tighten the specification, but the intent is clear: to
compare addresses, programmers use U<, not <.  And implementors better
make sure that this works.

- 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 2013: http://www.euroforth.org/ef13/

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Baden's recursive Quicksort revisited "Ed" <invalid@invalid.com> - 2013-10-11 01:31 +1000
  Re: Baden's recursive Quicksort revisited albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-10-10 15:49 +0000
  Re: Baden's recursive Quicksort revisited anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-10 17:42 +0000
    Re: Baden's recursive Quicksort revisited "Ed" <invalid@invalid.com> - 2013-10-18 15:16 +1000
    Re: Baden's recursive Quicksort revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-20 03:18 -0500
      Re: Baden's recursive Quicksort revisited anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-21 16:33 +0000
  Re: Baden's recursive Quicksort revisited Hans Bezemer <the.beez.speaks@gmail.com> - 2013-10-11 12:03 +0200
    Re: Baden's recursive Quicksort revisited Alex McDonald <blog@rivadpm.com> - 2013-10-11 05:15 -0700
      Re: Baden's recursive Quicksort revisited "Ed" <invalid@invalid.com> - 2013-10-13 12:25 +1000
        Re: Baden's recursive Quicksort revisited "Alex McDonald" <blog@rivadpm.com> - 2013-10-13 08:59 +0100
          Re: Baden's recursive Quicksort revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-13 04:50 -0500
            Comparing addresses (was: Baden's recursive Quicksort revisited) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-15 15:17 +0000
              Re: Comparing addresses Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-15 14:34 -0500
                Re: Comparing addresses anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-16 14:15 +0000
                Re: Comparing addresses Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-20 02:51 -0500
                Re: Comparing addresses anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-22 11:18 +0000
                Re: Comparing addresses albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-10-22 13:26 +0000
                Re: Comparing addresses anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-22 13:39 +0000
                Re: Comparing addresses Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-22 13:30 -0500
                Re: Comparing addresses anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-23 07:48 +0000
                Re: Comparing addresses m.a.m.hendrix@tue.nl - 2013-10-23 23:49 -0700
                Re: Comparing addresses anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-24 09:01 +0000
        Re: Baden's recursive Quicksort revisited albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-10-13 12:06 +0000
          Re: Baden's recursive Quicksort revisited all2001@spambog.com (Wolfgang Allinger) - 2013-10-13 11:42 -0400
    Re: Baden's recursive Quicksort revisited "Ed" <invalid@invalid.com> - 2013-10-13 12:27 +1000
      Re: Baden's recursive Quicksort revisited Hans Bezemer <the.beez.speaks@gmail.com> - 2013-10-16 10:35 +0200
        Re: Baden's recursive Quicksort revisited Andrew Haley <andrew29@littlepinkcloud.invalid> - 2013-10-16 03:51 -0500
        Re: Baden's recursive Quicksort revisited albert@spenarnc.xs4all.nl (Albert van der Horst) - 2013-10-16 10:50 +0000
          Re: Baden's recursive Quicksort revisited anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-16 14:27 +0000
        Re: Baden's recursive Quicksort revisited "Ed" <invalid@invalid.com> - 2013-10-18 15:37 +1000

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