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Re: Operating with binary numbers

• To: mathgroup at smc.vnet.net
• Subject: [mg59075] Re: Operating with binary numbers
• From: "Carl K. Woll" <carlw at u.washington.edu>
• Date: Thu, 28 Jul 2005 02:26:42 -0400 (EDT)
• Organization: University of Washington
• References: <dc77gl$k5p$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

"Wishmaster" <wishmaster at imaginary.marreka.no-ip.com> wrote in message 
news:dc77gl$k5p$1 at smc.vnet.net...
> Hello,
>
> I found that you can represent binary numbers in Mathematica with this:
>
> binary = 2^^110110101010111010
> 223930
>
> And BaseForm[binary, 10] returns the number in decimal form
>  223930
>
> I'd like to know if is there some function to test if a given bit of the
> binary number is on, and to do operations like "shifting" the binary 
> number.
> I looked at the help but can't find anything.
>
> I use Mathematica 5.0 on Windows XP.
>

To test whether a bit is on, use BitAnd. The following tests the last 5 
digits of binary:

In[7]:=
Positive[BitAnd[binary,2^{4,3,2,1,0}]]

Out[7]=
{True,True,False,True,False}

For shifting binary numbers, you may use the BitShift* functions in the 
Developer` context:

Developer`BitShiftRight
Developer`BitShiftLeft

Carl Woll
Wolfram Research

> Thanks.
> -- 
> []s Renan (aka Wishmaster) - Canoas, RS, Brazil
> "Rumor has it that, when they shut down the IBM 7094 at MIT in 1973,
> they found a low-priority process that had been submitted in 1967 and had
> not yet been run. "           -- From Silbershatz and Galvin, pp. 142-143.
>