title: What does func means in R-Format instruction set?
body: <p>I am very new to <strong>Assembly language</strong>. I was reading about <strong>MIPS</strong> architecture and I am stuck with the last field of the <strong>Register Format (R-Format)</strong>. Here is its visual representation,
  <img src="https://i.stack.imgur.com/OU8up.png" alt="enter image description here">
  Can anyone please help me out with <strong>what does the sixth field means</strong> and how do we calculate it?
  Thanks in advance.</p>