title: What's an offset?
body: <p>I keep seeing the offset word in MIPS instruction tables like <a href="http://www.mrc.uidaho.edu/mrc/people/jff/digital/MIPSir.html" rel="nofollow">this one</a>:</p>
  
  <pre><code>+--------------------------------------------------------------+
  |                           BEQ                                |
  +--------------------------------------------------------------+
  | Description:                                                 |
  |                                                              |
  | Branches if the two registers are equal                      |
  +--------------------------------------------------------------+
  | Operation:                                                   |
  |                                                              |
  | if $s == $t advance_pc (offset &lt;&lt; 2)); else advance_pc (4);  |
  +--------------------------------------------------------------+
  | Syntax:                                                      |
  |                                                              |
  | beq $s, $t, offset                                           |
  +--------------------------------------------------------------+
  | Encoding:                                                    |
  |                                                              |
  | 0001 00ss ssst tttt iiii iiii iiii iiii                      |
  +--------------------------------------------------------------+
  </code></pre>
  
  <p>What's an offset exacly?</p>