CS250 Final Exam Homework


a) Solve this homework and turnin your handwritten or printed answers before the final exam. You will find similar questions in the final exam. I will post the solutions one day before the final exam. I strongly suggest you to complete your homework on your own before looking at the solutions.

b) The final exam will be cumulative but it will concentrate in the second half of the semester. To prepare for the final review also the material of the first half of the semester.

1. Assume the virtual address 0x45674237 and a page size of 4KB and a 32 bit architecture.

a) obtain the page number and the offset.
b) Obtain the first-level index and the second-level index from the page number assuming that each of them is 10 bits long.
c) Draw a first-level page table and one second-level page table that will translate the above virtual address to address 0x83467237

2. Assuming a 32 bit architecture and a 4KB page size, how many first level page tables are needed for a single process? How many second-level page tables are needed for a single process?

3. Enumerate the page bits in the page table and what each of them is used for.

4. Enumerate the five uses of virtual memory used to speed up the execution of a program.

5. Explain how copy-on-write works during fork().

6. Explain how allocating memory initiallized with zeros is accelerated by using Virtual Memory.

7. Explain what is L1, L2, L3 cache.

8. Explain what is locality of reference.

9. Explain in what situations a memory cache will not give good results.

10. Explain how it is possible in a direct mapping memory cache that two items that are frequently used cannot be stored in the cache simultaneously.

11. Explain how buffers are used to reduce the numbers of system calls and device activity in a computer system.

12. Explain the steps of a interrupt.

13. Explain the steps to process a page fault.

14.In x86-64 Assembly language implement the function int addarray(int n, int * array) that add all the elements of the array
passed as parameter. n is the length of the array.




15. In x86-64 Assembly language implement a program "maxmin" that prompts two integer numbers fom stdin and then displays the maximum, minimum and average of both: numbers. Here is an example of the usage:

bash> maxmin
a=5
b=8
max=8
min=5
avg=6






16. From your lab8 compiler, complete the following code for function definition. Add comments describing your code.
function:
         var_type WORD
         {
		 



	 }
	 LPARENT arguments RPARENT compound_statement
         {
		 




         }
	;
17. From your lab8 compiler, complete the following code for sddition and substraction. Add comments describing your code.

    additive_expr:
          multiplicative_expr
	  | additive_expr PLUS multiplicative_expr {
		

	  }
	  | additive_expr MINUS multiplicative_expr {
	
	  }

 ;

18. From your lab8 compiler, complete the following code for WHILE loop. Add comments describing your code.

statement:
         assignment SEMICOLON
	 ...
	 | WHILE LPARENT expression RPARENT statement
	 ...
	 ;

19. From your lab8 compiler, complete the following code for assignment. Add comments describing your code.

assignment:
         WORD EQUAL expression
	 | WORD LBRACE expression RBRACE EQUAL expression
	 ;