title: What is 0xFF and why is it shifted 24 times?
body: <pre><code>#define SwapByte4(ldata) \
     (((ldata &amp; 0x000000FF) &lt;&lt; 24) | \
     ((ldata &amp; 0x0000FF00) &lt;&lt; 8) | \
     ((ldata &amp; 0x00FF0000) &gt;&gt; 8) | \
     ((ldata &amp; 0xFF000000) &gt;&gt; 24))
  </code></pre>
  
  <p>What does that 0x000000FF represent?  I know that decimal 15 is represented in hex as F, but why is it &lt;&lt; 24?</p>