Peer Review

1. Part 1 and 2 are not done.

2. The code does not give correct output.

3.

One problem is that your not saving $a0 and $a1 before advancing them for the recursive call. Because $a0 and $a1 are caller-saved registers. That means when you call decode recursively, the recursive call can overwrite $a0 and $a1. So save the original $a0 and $a1 on the stack before recursion, then restore after.