the protothread loop until the protothread is</span>
<span class="comment">   * expliticly exited with PT_EXIT().</span>
<span class="comment">   */</span>
  <span class="keywordflow">while</span>(1) {

    <span class="comment">/*</span>
<span class="comment">     * We'll be reading key presses until we get the right amount of</span>
<span class="comment">     * correct keys.</span>
<span class="comment">     */</span> 
    <span class="keywordflow">for</span>(keys = 0; keys &lt; <span class="keyw