solve part b

Question-4 [Hazards and Unrolling) (26 pts] This question has three parts (a through c) (a) Identify all RAW, WAW and WAR dependencies in the loop shown below. Write down the dependencies within a 'single iteration only. Use the following notation, for example, to indicate a dependency between Ix and ly through r3 register: Ix->ly (r3). ('$zero' represents a register that is hardwired to value 0, and 'mul' is opcode for multiplication): (8 pts) loop: 11: lw $1,0 r1) 12: mul s2, 51, 50 13: add 53, 53, 52 14: mul s2, s1, s1 15: add 52, 52, 53 16: sw $2,0(1) 17: sub r1, r1,8 18:bne r1, Szero, loop (b) Unroll the loop above once and eliminate as many dependences as you can via 'register renaming' What dependences remain after renaming? Why can't they be eliminated via renaming? (8 pts) (c) Two important techniques have emerged recently for achieving high performance in processors. One is 'speculative execution', where instructions (or sequences of instructions) are executed before all the information needed to commit the instruction has been nailed down. The other is simultaneous multithreading' (SMT), where the processor can issue instructions from multiple threads (or processes). potentially in the same cycle. Describe the pros and cons of each approach with respect to the other. Do these approaches capture different opportunities for parallelism, or are they different ways to achieve the same result? if both were implemented in a single system, would you expect their projected improvements to be additive? Why or why not? (10 pts) SV