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Re: The problem with implementation defined behaviour.

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: The problem with implementation defined behaviour.
Date 2016-04-01 11:44 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2016Apr1.134404@mips.complang.tuwien.ac.at> (permalink)
References (5 earlier) <5d973aa6-707b-4e4b-b510-2f62acf80c5d@googlegroups.com> <2016Mar31.125525@mips.complang.tuwien.ac.at> <ea6d7906-5957-4311-a265-02c3038153ce@googlegroups.com> <h4idndgL64APGWDLnZ2dnUU7-NnNnZ2d@supernews.com> <fbf6d82f-953c-45f1-a918-4da4a9df45b7@googlegroups.com>

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mhx@iae.nl writes:
>On Thursday, March 31, 2016 at 10:12:03 PM UTC+2, Elizabeth D. Rather wrote:
>> On 3/31/16 3:38 AM, mhx@iae.nl wrote:
>> >> The M*/ speed is great.  You obviously found a much better
>> >> >implementation than we did.
>> > There is some triple-length stuff inside which is apparently
>> > quite efficient / easy for the CPU.
>> 
>> The native multiply on virtually all CPUs leaves a double product in 
>> registers. Likewise, virtually all native divisions divides a single 
>> into a double in those registers. Therefore, it's a piece of cake in 
>> assembler. 
>
>I assumed that m*/ has the stack picture ( d1 n1 n2 -- d1*n1/n2 ).
>Therefore, d1*n1 might overflow into a triple length number
>(unsupported by the CPU),

Correct.  The specification of M*/ starts with 

|Multiply d1 by n1 producing the triple-cell intermediate result t.
|Divide t by +n2 giving the double-cell quotient d2.

- 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
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The problem with implementation defined behaviour. Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-29 14:39 +0000
  Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-29 16:20 +0000
    Re: The problem with implementation defined behaviour. "Elizabeth D. Rather" <erather@forth.com> - 2016-03-29 09:16 -1000
      Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-30 00:06 +0000
        Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-03-29 22:09 -0700
          Re: The problem with implementation defined behaviour. "Elizabeth D. Rather" <erather@forth.com> - 2016-03-29 21:37 -1000
          Re: The problem with implementation defined behaviour. Paul Rubin <no.email@nospam.invalid> - 2016-03-30 00:48 -0700
            Re: The problem with implementation defined behaviour. Paul Rubin <no.email@nospam.invalid> - 2016-03-30 00:48 -0700
          Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-30 07:59 +0000
            Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-03-30 10:16 -0700
              Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-30 23:43 +0000
                Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-03-31 06:01 -0700
                Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-01 21:36 +0000
                Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-04-01 14:57 -0700
                Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-01 21:59 +0000
                Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-04-02 00:51 -0700
                Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-04-01 08:25 +0000
                Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-01 21:32 +0000
                division performance (was: The problem with implementation defined ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-04-05 11:12 +0000
                Re: division performance (was: The problem with implementation defined ...) Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-05 20:45 +0000
                Re: division performance (was: The problem with implementation defined ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-04-06 10:03 +0000
                Re: division performance (was: The problem with implementation defined ...) Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-08 22:53 +0000
                Re: division performance (was: The problem with implementation defined ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-04-09 10:14 +0000
                Re: division performance (was: The problem with implementation defined ...) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-04-09 13:43 +0000
              Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-31 10:55 +0000
                Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-03-31 06:38 -0700
                Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-31 16:21 +0000
                Re: The problem with implementation defined behaviour. Paul Rubin <no.email@nospam.invalid> - 2016-03-31 11:49 -0700
                Re: The problem with implementation defined behaviour. "Elizabeth D. Rather" <erather@forth.com> - 2016-03-31 10:11 -1000
                Re: The problem with implementation defined behaviour. mhx@iae.nl - 2016-04-01 03:53 -0700
                Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-04-01 11:44 +0000
                Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-01 21:53 +0000
                Re: The problem with implementation defined behaviour. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-04-02 11:46 -0500
                Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-04-02 21:43 +0000
                Re: The problem with implementation defined behaviour. Andrew Haley <andrew29@littlepinkcloud.invalid> - 2016-04-03 03:17 -0500
                Re: The problem with implementation defined behaviour. hughaguilar96@gmail.com - 2016-04-01 23:54 -0700
          Re: The problem with implementation defined behaviour. Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-30 12:58 +0000
          Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-30 22:22 +0000
        Re: The problem with implementation defined behaviour. Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-30 12:55 +0000
      Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-30 07:44 +0000
        Re: The problem with implementation defined behaviour. Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-30 13:08 +0000
          Re: The problem with implementation defined behaviour. anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2016-03-30 13:43 +0000
        Re: The problem with implementation defined behaviour. Bernd Paysan <bernd.paysan@gmx.de> - 2016-03-30 22:06 +0000
      Re: The problem with implementation defined behaviour. trevor <tgritchie@blueyonder.co.uk> - 2016-03-30 13:13 +0100
        Re: The problem with implementation defined behaviour. Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-30 13:56 +0000
      Re: The problem with implementation defined behaviour. Albert van der Horst <albert@spenarnc.xs4all.nl> - 2016-03-30 12:49 +0000

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