title: 32 bit PPC rlwinm instruction
body: <p>I'm having a bit of trouble understanding the <code>rlwinm</code> PPC Assembly instruction (Rotate Left Word Immediate Then AND with Mask).</p>
  
  <p>I am trying to reverse this part of a function</p>
  
  <pre><code>rlwinm r3, r3, 0, 28, 28
  </code></pre>
  
  <p>I already know what <code>r3</code> is. <code>r3</code> in this case is a 4 byte integer but I am not sure exactly what this instruction <code>rlwinm</code> is doing to it.</p>
  
  <p>By the way, this is on a 32 bit machine. </p>