Editing Bitwise operation (section)

==Applications==
Bitwise operations are necessary particularly in lower-level programming such as device drivers, low-level graphics, communications protocol packet assembly, and decoding.

Although machines often have efficient built-in instructions for performing arithmetic and logical operations, all these operations can be performed by combining the bitwise operators and zero-testing in various ways.<ref>{{cite web|url=http://bisqwit.iki.fi/story/howto/bitmath/ |title=Synthesizing arithmetic operations using bit-shifting tricks |publisher=Bisqwit.iki.fi |date=15 February 2014 |access-date=8 March 2014}}</ref>  For example, here is a [[pseudocode]] implementation of [[ancient Egyptian multiplication]] showing how to multiply two arbitrary integers <code>a</code> and <code>b</code> (<code>a</code> greater than <code>b</code>) using only bitshifts and addition:

<syntaxhighlight lang="c">
c ← 0
while b ≠ 0
    if (b and 1) ≠ 0
        c ← c + a
    left shift a by 1
    right shift b by 1
return c
</syntaxhighlight>

Another example is a pseudocode implementation of addition, showing how to calculate a sum of two integers <code>a</code> and <code>b</code> using bitwise operators and zero-testing:

<syntaxhighlight lang="c">
while a ≠ 0
    c ← b and a
    b ← b xor a
    left shift c by 1
    a ← c
return b
</syntaxhighlight>