title: How does `Skipcond` work in the MARIE assembly language?
body: <p>I am trying to understand the MARIE assembly language. I don't quite understand <code>skipcond</code> for
  doing things like <code>&lt;</code>, or <code>&gt;</code>, or multiply or divide.</p>
  
  <p>I am taking this simple program:</p>
  
  <pre><code>x = 1
  while x &lt; 10 do
  x  = x +1
  endwhile;
  </code></pre>
  
  <p>What I don't understand is how to use certain skip conditions:</p>
  
  <pre><code>Skipcond 800 if AC &gt; 0,
  Skipcond 400 if AC = 0,
  Skipcond 000 if AC &lt; 0
  </code></pre>
  
  <p>Now, I know I would subtract x from 10 and test using skipcond.</p>
  
  <p>I am not sure which one and why. I guess if I knew how they really work maybe it would be easier to understand. Why is it used to compare to zero?</p>
  
  <p>This is what I have:</p>
  
  <pre><code>100     load one
  101     store x
  102     subt ten
  103     skipcond400  if x-10 = 0?   // or skpcond000 x -10 &lt; 0?? 
  </code></pre>