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Re: Simpler way to dp binary logical operation using arithmetic?

From "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups comp.programming
Subject Re: Simpler way to dp binary logical operation using arithmetic?
Date 2018-09-10 22:00 +0200
Organization Aioe.org NNTP Server
Message-ID <pn6ig9$1kus$1@gioia.aioe.org> (permalink)
References <bx7o6lmzra8t.mz0g7tl4wryj.dlg@40tude.net> <pn66bt$uhj$1@gioia.aioe.org> <tsnbp9qh2k01$.4skcz5j2hgya.dlg@40tude.net>

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On 2018-09-10 21:26, JJ wrote:
> On Mon, 10 Sep 2018 18:32:58 +0200, Dmitry A. Kazakov wrote:

>> P.P.P.S. What about a language that has modulo 2**n numbers AKA binary
>> unsigned numbers. Bitwise operations are defined on them.
> 
> I'm not sure what you meant, sorry. The only supported modulo operation is
> the `%` operator.

Modular arithmetic is like this:

    1 + 0 = 1 (mod 3)
    1 + 1 = 2 (mod 3)
    1 + 2 = 0 (mod 3)
    1 + 3 = 1 (mod 3)
    1 + 4 = 2 (mod 3)
    1 + 5 = 0 (mod 3)

etc.

See

    https://en.wikipedia.org/wiki/Modular_arithmetic

Bitwise operations are mathematically defined only on power of 2 modulo. 
This kind of arithmetic has nothing to do with integer arithmetic except 
for sharing numerals, names of operations, some properties of 
corresponding operations.

Decent languages have different numeric types for modular integers and 
"normal" integers.

> The application doesn't support any bitwise operation at all. It's pretty
> limited, really. It doesn't support bit shifting operators.

Arithmetic shift by n in modular arithmetic of modulo of power of 2 is 
equivalent to multiplication by 2**n (in both arithmetics), provided you 
can suppress integer overflows.

> It doesn't even
> support custom function. i.e. it's not possible to create my own function.

Why do you bother with that then? (:-)) Life is too short... (:-()

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de

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Thread

Simpler way to dp binary logical operation using arithmetic? JJ <jj4public@vfemail.net> - 2018-09-10 22:56 +0700
  Re: Simpler way to dp binary logical operation using arithmetic? Julio Di Egidio <julio@diegidio.name> - 2018-09-10 09:30 -0700
    Re: Simpler way to dp binary logical operation using arithmetic? JJ <jj4public@vfemail.net> - 2018-09-11 02:13 +0700
      Re: Simpler way to dp binary logical operation using arithmetic? Julio Di Egidio <julio@diegidio.name> - 2018-09-10 14:21 -0700
  Re: Simpler way to dp binary logical operation using arithmetic? "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2018-09-10 18:32 +0200
    Re: Simpler way to dp binary logical operation using arithmetic? JJ <jj4public@vfemail.net> - 2018-09-11 02:26 +0700
      Re: Simpler way to dp binary logical operation using arithmetic? "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> - 2018-09-10 22:00 +0200
        Re: Simpler way to dp binary logical operation using arithmetic? JJ <jj4public@vfemail.net> - 2018-09-11 03:22 +0700
  Re: Simpler way to dp binary logical operation using arithmetic? David Brown <david.brown@hesbynett.no> - 2018-09-10 18:50 +0200
    Re: Simpler way to dp binary logical operation using arithmetic? JJ <jj4public@vfemail.net> - 2018-09-11 03:02 +0700
      Re: Simpler way to dp binary logical operation using arithmetic? nobody@example.org (Scott) - 2018-09-11 15:24 +0000
  Re: Simpler way to dp binary logical operation using arithmetic? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-09-10 18:59 +0100
    Re: Simpler way to dp binary logical operation using arithmetic? JJ <jj4public@vfemail.net> - 2018-09-11 03:08 +0700

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