title: dividing by two in binary numbers
body: <p>how can I divide a binary number (in 2 complement) by 2 . <br> 
  I've tried bit shifting but I have a problem with negative odd numbers, how can I solve it? 
  for example : </p>
  
  <pre><code>(-7/2) 11001/2 =&gt; (shifts the number one place to the right) =&gt; 11100 (-4)
  </code></pre>