title: trying to understand the assembly instruction: cltd on x86
body: <p>I found the assembly instruction</p>
  
  <pre><code>cltd
  </code></pre>
  
  <p>by disassembling code on an Intel architecture. The description I found was, that it clears the %edx register, but I don't understand what happens.... can anyone explain what the command exactly does?</p>