title: Why does PRINT'ing a true boolean expression output -1?
body: <p>In Commodore 64 BASIC V2, PRINT'ing a true boolean expression outputs -1:</p>
  
  <pre><code>READY.
  A=(5=5)
  
  READY.
  PRINT A
  -1
  </code></pre>
  
  <p>Why -1 and not 1?</p>
  
  <p><img src="https://i.stack.imgur.com/bZBJA.png" alt="enter image description here"></p>