title: How to reverse bitwise AND (&) in C?
body: <p>How to reverse bitwise AND (&amp;) in C?</p>
  
  <p>For example I have an operation in C like this:</p>
  
  <pre><code>((unsigned int)ptr &amp; 0xff000000))
  </code></pre>
  
  <p>The result is <code>0xbf000000</code>. What I need at this moment is how to reverse the above, i.e. determine <code>ptr</code> by using the result from the operation and of course <code>0xff000000</code>. </p>
  
  <p>Is there any simple way to implement this in C?</p>