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bitwise operators(info)

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  bitwise operators(info) Ceriousmall <divadsmall@gmail.com> - 2012-01-27 13:56 -0800
    Re: bitwise operators(info) John Gordon <gordon@panix.com> - 2012-01-27 22:03 +0000
    Re: bitwise operators(info) "Morris Keesan" <mkeesan@post.harvard.edu> - 2012-01-27 17:35 -0500
      Re: bitwise operators(info) Ceriousmall <divadsmall@gmail.com> - 2012-01-27 16:22 -0800
    Re: bitwise operators(info) Devil with the China Blue Dress <chine.bleu@yahoo.com> - 2012-01-27 16:52 -0800
      Re: bitwise operators(info) Keith Thompson <kst-u@mib.org> - 2012-01-27 17:06 -0800
        Re: bitwise operators(info) Harald van Dijk <truedfx@gmail.com> - 2012-01-27 19:06 -0800
          Re: bitwise operators(info) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-28 11:33 +0000
            Re: bitwise operators(info) James Kuyper <jameskuyper@verizon.net> - 2012-01-28 13:46 -0500
              Re: bitwise operators(info) Kaz Kylheku <kaz@kylheku.com> - 2012-01-28 19:01 +0000
              Re: bitwise operators(info) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-28 22:41 +0000
                Re: bitwise operators(info) Ceriousmall <divadsmall@gmail.com> - 2012-01-28 21:19 -0800
                  Re: bitwise operators(info) Keith Thompson <kst-u@mib.org> - 2012-01-29 02:13 -0800
                  Re: bitwise operators(info) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-29 14:59 +0000
                    Re: bitwise operators(info) pete <pfiland@mindspring.com> - 2012-01-29 10:51 -0500
                  Re: bitwise operators(info) ImpalerCore <jadill33@gmail.com> - 2012-01-30 10:25 -0800
                    Re: bitwise operators(info) Ceriousmall <divadsmall@gmail.com> - 2012-01-31 06:00 -0800
                      Re: bitwise operators(info) Ben Bacarisse <ben.usenet@bsb.me.uk> - 2012-01-31 14:30 +0000
                        Re: bitwise operators(info) pete <pfiland@mindspring.com> - 2012-01-31 10:06 -0500
            Re: bitwise operators(info) Harald van Dijk <truedfx@gmail.com> - 2012-01-28 12:34 -0800
        Re: bitwise operators(info) Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-01-27 22:56 -0500
          Re: bitwise operators(info) Keith Thompson <kst-u@mib.org> - 2012-01-27 20:30 -0800
            Re: bitwise operators(info) Shao Miller <sha0.miller@gmail.com> - 2012-01-29 09:27 -0500
          Re: bitwise operators(info) Kaz Kylheku <kaz@kylheku.com> - 2012-01-28 05:16 +0000
    Re: bitwise operators(info) Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2012-01-27 21:44 -0700

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#16337

On 1/27/2012 8:06 PM, Keith Thompson wrote:
>
> In fact an int is represented in binary on any conforming
> implementation; see C99 6.2.6.2.

     I've invented a four-state device that is 7% faster, 18% less
power-hungry, and 31% cheaper to manufacture than a pair of two-
state devices.  I'm building a revolutionary new computer based on
these devices, storing values as 0,1,2,3 "quits" instead of as pairs
of 0,1 "bits."  Is my C implementation doomed to be non-conforming?

-- 
Eric Sosman
esosman@ieee-dot-org.invalid

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#16340

Eric Sosman <esosman@ieee-dot-org.invalid> writes:
> On 1/27/2012 8:06 PM, Keith Thompson wrote:
>> In fact an int is represented in binary on any conforming
>> implementation; see C99 6.2.6.2.
>
>      I've invented a four-state device that is 7% faster, 18% less
> power-hungry, and 31% cheaper to manufacture than a pair of two-
> state devices.  I'm building a revolutionary new computer based on
> these devices, storing values as 0,1,2,3 "quits" instead of as pairs
> of 0,1 "bits."  Is my C implementation doomed to be non-conforming?

Not if you manage to make it *look* like everything is made of bits.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
    Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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#16387

On 1/27/2012 23:30, Keith Thompson wrote:
> Eric Sosman<esosman@ieee-dot-org.invalid>  writes:
>> On 1/27/2012 8:06 PM, Keith Thompson wrote:
>>> In fact an int is represented in binary on any conforming
>>> implementation; see C99 6.2.6.2.
>>
>>       I've invented a four-state device that is 7% faster, 18% less
>> power-hungry, and 31% cheaper to manufacture than a pair of two-
>> state devices.  I'm building a revolutionary new computer based on
>> these devices, storing values as 0,1,2,3 "quits" instead of as pairs
>> of 0,1 "bits."  Is my C implementation doomed to be non-conforming?
>
> Not if you manage to make it *look* like everything is made of bits.
>

Yeah.  A difference that makes no difference is no difference.

The context is "bitwise operators," which work with bits. :)  Since 
inspecting the object representation must be possible, any difference 
between abstract machine and physical representation seems out-of-scope.

-- 
"The stationery store has moved.  Aaargh!"

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#16344

On 2012-01-28, Eric Sosman <esosman@ieee-dot-org.invalid> wrote:
> On 1/27/2012 8:06 PM, Keith Thompson wrote:
>>
>> In fact an int is represented in binary on any conforming
>> implementation; see C99 6.2.6.2.
>
>      I've invented a four-state device that is 7% faster, 18% less
> power-hungry, and 31% cheaper to manufacture than a pair of two-
> state devices.  I'm building a revolutionary new computer based on
> these devices, storing values as 0,1,2,3 "quits" instead of as pairs
> of 0,1 "bits."  Is my C implementation doomed to be non-conforming?

I always suspected you'd be calling it quits.

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#16342

Ceriousmall <divadsmall@gmail.com> writes:

> Can anyone here point me towards any documentation that explains
> bitwise operations in C in a simple manner. After K&R Chap 2.9
> introduction to the bitwise operator I'm still in the dark. Basically
> I take out my paper take two integers convert them into their binary
> form and  compare them using the rules of the bitwise operartors to
> yield a result then convert that value back to decimal.......

You're not going to like this, but:  that section strikes me as crystal
clear -- you just need to think in binary.  The bitwise operators are
about, well, bits.  Translating back and forth to decimal adds a bunch
of complexity, and makes things much harder to understand.

Translating back and forth to octal or hex is pretty much automatic once
you're really thinking in binary.

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