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peter86

Bitwise OR and AND

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would you like coffee OR tea?
would you like coffee AND tea?
would you like coffee XOR tea?

simple, isn''t it?

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For bitwise OR(|) the result is 1 if either of the two bits is 1.

For bitwise AND(&) the result is 1 if BOTH of the two bits is 1, and always 0 otherwise.

For bitwise XOR(^) called "exclusive or" the result is 1 if either of the two bits is 1, BUT NOT IF BOTH are 1 or BOTH are 0.


"aut viam inveniam aut faciam " - I will either find a way or make one.

MoonStar Projects

[edited by - Ronin Magus on December 27, 2002 11:12:21 AM]

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Just a note; in normal language, "or" is usually equivalent to logical eXclusive OR (XOR). The expression "and/or" is equivalent to logical OR.

So,
OR.: would you like coffee and/or tea?
AND: would you like coffee and tea?
XOR: would you like coffee or tea?


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ex-or. It is, after all, short for "exclusive". And exclusive doesn''t have a z in it.


Don''t listen to me. I''ve had too much coffee.

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quote:
Original post by krez
neither does xylophone or xebra...


if you refer to the zebra (the black''n''white horse style animal) here, uhm, yes, it actually does.
xylophone is spoken gsilofon here :D(okay, ex-ilophone for you, i think)

"take a look around" - limp bizkit
www.google.com

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And I? ex-a ex-a?

Just to avoid being deleted:

Given two binary numbers: 0100101010 (298)
1101011011 (859)


binary dec
0100101010 (298)
AND 1101011011 (859)
----------
0100001010 (266)
___________________________

0100101010 (298)
OR 1101011011 (859)
----------
1101111011 (891)
___________________________

0100101010 (298)
XOR 1101011011 (859)
----------
1001110001 (625)

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quote:
Original post by Zipster
Say, I noticed that the XOR operation was like an addition operation without the carry! Care to elaborate?

True, or rather that addition is xor with carry

Here's a diagram for a full-adder (if I get it right, that is ):

si = (ai XOR bi) XOR ci;
ci+1 = ai * bi + (ai OR bi) * ci;

ci o-----------------------+
  |
  +-----+ | +-----+
ai o-----+-->| | +--|-->| |
  | | XOR |>---+ | | XOR |>-------------------o si
  +--|-->| | | +-->| |
  | | +-----+ | | +-----+
  | | | |
  | | +-----+ | | +-----+ +-----+
  | +-->| | +--|-->| | +----->| |
  | | AND |>-+ | | AND |>--+ | OR |>--o ci+1
bi o--+----->| | | +-->| | +-->| |
  +-----+ | +-----+ | +-----+
  | |
  +---------------------+

a = input bit 1
b = input bit 2
s = sum
c = carry

EDIT: Some formatting




[edited by - CWizard on December 28, 2002 5:54:46 AM]

[edited by - CWizard on December 28, 2002 5:58:11 AM]

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