title: mips printing characters
body: <pre><code>li $a0, '0'
  li $v0, 11
  syscall
  </code></pre>
  
  <p>so I have this code to print what is in $a0</p>
  
  <p>In terms of characters being printed out what is the difference
  between -1 and 1? When I try to print -1 instead 0, mars just complains about the value.</p>
  
  <p>Is there any mathematical function to handle negative numbers in terms of positive numbers?</p>