Midterm Exam, CSCI 312, Spring 2010

• Make sure you answer each question completely and thoughtfully.
• Please make sure your answers are clearly labeled with the question number.
• Please write neatly and make any diagrams as neat as you can. If I can't read it, it is wrong.
• Point values are listed by each question.

1. (5 points) What is an instruction set architecture (ISA)?
2. (5 points) Why is clock speed an insufficient measure of performance?
3. (10 points) Describe the impact of each of the following on performance.
   • Algorithm
   • Programmer
   • Compiler
   • ISA
4. (10 points) Assume that a program requires 1 x 10⁶ compute, 5 x 10⁵ load/store, and 5 x 10 ⁵ branch operations. Assuming a compute takes 1 cycle, load/store 10 cycles, and a branch 3 cycles on a 3GHz processor.
   1. Compute the CPI for this program on this machine.
   2. Compute the time required for this program to run on this machine.
5. (5 points) Using the computer described in the previous question. Assume performance is defined in terms of the fastest program which can be run on this computer.
   1. Describe this program.
   2. What is the CPI for this program?
6. (10 points) Describe three functions performed by an assembler.
7. (10 points) A company produces 1000 different types of items. Each item comes in 4 sizes and can be one of 29 different colors. Design an efficient system for providing a model number which includes the item type, size and color. Explain your system.
   1. Where is this system efficient?
   2. How is it inefficient?
   3. How much product/feature growth can the company sustain with your encoding system?
8. (5 points) Give three disadvantages of programming in assembly language.
9. (5 points) Describe the difference between general purpose and special purpose registers. Give an example of each in the MIPS ISA.
10. (5 points) Explain the Memory Allocation figure on the back of the "Green Sheet". What is stored in each region?
11. (5 points) What are the MPIS pseudoinstructions? Why are they provided? What "implements" these instructions and how?
12. (5 points) What is the purpose of the $zero register int he MPIS instruction set? Give a non-trivial example of the use of this register.
13. (5 points) A princess was born 1.26x10⁶ Antarian Periods ago.
    • There are 2 Omicron-Persei-8 years in an Anterian year.
    • There are 900 Antarian Periods in an Anterian month and 4 Antarian months in an Antarian year.
    • There are 3 Earth year in a single Coruscant Solar Cycle.
    • There are 100 Omicron-Persei-8 years in a Coruscant Solar Cycle.
    How old is the princess on earth? Show your computation in a manner can be verified by others.