There will be a quiz in this recitation.
It will be a closed book exam. You may not use a computer.
You should bring a calculator that can do add, subtract, multiply, divide, powers (y^x), and logs.
The quiz will consist of three questions and each problem is worth 3 points:

• 1 point for turning in the paper
• 2 points for showing some reasonable work
• 3 points for showing work and getting the correct answer and putting a box around it

The first question will ask you to list the mnemonics in order for the 5 cycles of the pipeline.
The second question will concern what a particular instruction does during a particular stage of the pipeline.
The third question will concern calculating speedup.
After turning in the quiz, start on the problems below.

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The first problem is carried over from last time and will be covered as necessary.
Problems from Recitation 2, that were not finished last week will be discussed.

1. Suppose you have two programs you are going to run. 50% of Program A can be enhanced with a speedup of 2 and 90% of Program B can be enhanced with a speedup of 2.
   1. What is the overall speedup for Program A?
   2. What is the overall speedup for Program B?
   3. If when run together before enhancement, the Program A uses 80% of the resources and Program B uses 20% of the resources, what is the overall speedup when the two programs are run together?
2. Machine A executes integer instructions 30% faster than machine B, but machine B executes floating point instructions 50% faster than machine A. On other instructions the machines are the same speed. If a task on A spends 40% of its time executing integer instructions and 30% of its time executing floating point instructions, which machine is faster and what is the speedup?
3. Suppose you have two programs you are going to run. 50% of Program A can be enhanced with a speedup of 2 and 90% of Program B can be enhanced with a speedup of 2.
   1. What is the overall speedup for Program A?
   2. What is the overall speedup for Program B?
   3. If when run together before enhancement, the Program A uses 80% of the resources and Program B uses 20% of the resources, what is the overall speedup when the two programs are run together?
4. For the 5-stage pipeline, describe what is done at each stage of the pipeline for the following instruction. Only include what is needed to execute this instruction, but be sure to state what happens to each pipeline register.
      LD R3, 5(R4)
5. For each of the following sequences of instructions, determine the number of stall cyles needed for execution, both with and without forwarding.

   1.    DADD  R1, R2, R3
         DSUB  R4, R1, R5
         AND   R6, R1, R7
         

   2.    LD    R1, 8(R2)
         DSUB  R4, R1, R5
         AND   R6, R7, R8
         

6. Find a method (other than forwarding) of reducing the number of stalls in part b) of the above problem.