Note: If a data hazard is NOT prevented by data forwarding, then the pipeline stalls. Assume data forwarding is working, does the following code stall? "stall" means it needs an extra nop instruction inserted If the code stalls then list the labels of the instruction(s) that cause a stall. This question is asking if stall signal is set to '1', four cases.

L1: lw $3, 50($3)

L2: add $2, $3, $4

L3: sw $2, 20($2)

L4: lw $5, 30($2)

L5: lw $6, 40($5)

L6: or $5, $6, $5