CSC231 Sample Midterm Questions

--D. Thiebaut (talk) 08:32, 27 February 2017 (EST)

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Below are typical questions you might expect during the in-class CSC231 Midterm Exam

Question

Assume that eax, ebx, ecx, and edx all 4 contain the value 0 before the program below start. Indicate the value of each 32-bit register after each instruction has been executed.

        ;; eax = ebx = ecx = edx = 0x00000000                                                                       

	or	ax, 0xffff	; eax = __________                                                                  
        or	bl, 0xff	; ebx = __________                                                                  
        or	cx, 0xff	; ecx = __________                                                                  
        or	edx,0xffff0000	; edx = __________                                                                  
        and	ax, 0xff00	; eax = __________                                                                  
	and	bx, 0x0f	; ebx = __________

Question

What is a big-endian processor?

Question

Write a program that uses only one string of characters "********" and that prints this pattern:

********
******
****
**

Question

The RAM containing the data section of the program below is shown here, as a collection of successive bytes. The top byte has the lowest address of the group. In other words, addresses increase as we go down the array of bytes.

Show the contents of the RAM once the array has been initialized with the variables a, b, msg and c.

 

        section    .data
a       dd         10
b       dd         0x1234
msg     db         1,2,3,4,5,6,7
c       dw         0xaa

        +--------------+
        |              |
        +--------------+
	|              |
	+--------------+
        |              |
        +--------------+
        |              |
        +--------------+
        |              |
	+--------------+
        |              |
        +--------------+
        |              |
        +--------------+
        |              |
        +--------------+
	|              |
	+--------------+
        |              |
        +--------------+
        |              |
        +--------------+
        |              |
	+--------------+
        |              |
        +--------------+
        |              |
        +--------------+
        |              |
        +--------------+
        |              |
        +--------------+
        |              |
	+--------------+
        |              |
        +--------------+
        |              |
        +--------------+

Questions

• Convert the following hexadecimal numbers in binary

• 1
• 10
• 16

• Convert the following decimal numbers to binary

• 1
• 10
• 16

• Convert the following binary numbers to hexadecimal

• 1001
• 11001101
• 111000111000

• 'A' has ASCII code 0x41.

• What is the code for 'B'?
• What is 'A' + 0x20, in hex, in ASCII, or in decimal?