title: MIPS instruction questions
body: <p>Can the <code>subu</code> instruction in MIPS give me a negative result, or will the result always be positive since we are doing the unsigned version of the sub?
  Also, if I want to do arithmetic shift right, and put 1 at the 0th position of the number, should I use the <code>sra</code> instruction, or is there another instruction for it?</p>