In this exercise, we examine how data dependences affect execution in the basic $5-$stage pipeline described. Problems in this exercise refer to the following sequence of instructions:

Instruction

or r$1,$ r$2,$ r$3$

or r$2,$ r$1,$ r$4$

or r$1,$ r$1,$ r$2$

Assume the following cycle times for each of the options related to forwarding:

Forwarding Option

Cycle Time

Without Forwarding

$250$ ps

With Full Forwarding

$300$ ps

With ALU$-$ALU Forwarding Only

$290$ ps

Questions:

Question $1$: Indicate dependences and their type.

Question $2$: Assume there is no forwarding in this pipelined processor. Indicate hazards and add NOP instructions to eliminate them.