Not too hard to memorize zero.

### A good answer might be:

       0    0    0    0    0    0    0    0    -- machine instruction in hex

    0000 0000 0000 0000 0000 0000 0000 0000    -- machine instruction in bits

    000000 00000  00000 00000  00000 000000    -- fields of the instructuion

    opcode -----  $0    $0       0   2ndary    -- meaning of the fields

    sll         source  dest  shft   sll

# No-Op

Register $0 always contains a 32-bit zero (have you heard this before?) so shifting it left by zero positions and attempting to put the result back in $0 does nothing. Any instruction that attempts to alter $0 does nothing, but this instruction is the preferred way of doing nothing.

A machine instruction that does nothing is called (in official computer science jargon) a no-op. The no operation instruction is surprisingly useful, especially for MIPS.

### QUESTION 5:

What do you call a human who does nothing?