CSE 2421
lab4
Name: Chuhan Feng
Time taken: 2 hr
Problems encountered:
I didn't encounter any problem in this lab.
Questions:
1. loop $ instruction is used to result a time delay between two continuous
   shark fin movement. If there is no "loop $" in the code, the program will
   finish almost immidiately after it begins to run, then we will not be
   able to experience such an amazing shark simulation like that anymore! 
   (This is the core technology, which can never let others to know!!!)
2. The initial value of esi is 22.
3. The value of esi after second iteration is 21.
4. The final value of esi is 0.
5. esi is probably used for establishing loop invarient (esi > 0), which
   means that the initial value of esi determines how many times the shark
   fin should move.