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MathGroup Archive 2003

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Re: two's complement function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg44124] Re: two's complement function
  • From: Paul Abbott <paul at physics.uwa.edu.au>
  • Date: Thu, 23 Oct 2003 07:15:41 -0400 (EDT)
  • Organization: The University of Western Australia
  • References: <bmqqei$rk4$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

In article <bmqqei$rk4$1 at smc.vnet.net>, "Ken Morgan" <kemorgan at vt.edu> 
wrote:

> Can anyone think of a better way to produce a list of digits of a two's
> complement integer than the following?
> 
> tc[n_, bits_:32] :=
> If[Positive[n], IntegerDigits[n, 2, bits],
> IntegerDigits[FromDigits[IntegerDigits[n, 2, bits] /. {1 -> 0, 0 -> 1}, 2] +
> 1, 2, bits]]

Why not use bitwise operations? If you execute the following cell

   FrontEndExecute[FrontEnd`HelpBrowserLookup[
      "MainBookLink","Two's complement representation"]]

it will direct you to appropriate section of the online documentation.

Cheers,
Paul

-- 
Paul Abbott                                   Phone: +61 8 9380 2734
School of Physics, M013                         Fax: +61 8 9380 1014
The University of Western Australia      (CRICOS Provider No 00126G)         
35 Stirling Highway
Crawley WA 6009                      mailto:paul at physics.uwa.edu.au 
AUSTRALIA                            http://physics.uwa.edu.au/~paul


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