操作系统与系统级编程-2012-期末考试-A

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311046040 A

2012-2013-1

1. Compared to a sequence of machine code instructions, a fragment of C code

a. describes the actions of the computer, not just of the CPU b. does not engage any transistors during its

execution

c. is the native way to program most computers d. may describe the same algorithm

II. A 32-bit float only approximates decimal fractions, but a 64-bit double represents them exactly.

III. Floating-point numbers can represent any rational real number but not irrationals.

a. II only b. I and III only c. I and II only d. I only

4. In C, what is the following binary number in hexadecimal? 11010101

a. 0xAB b. 0x5D c. 0xB5 d. 0xD5

5. Which of the following statements about alignment within C struct's is true?

I . Alignment may cause the allocation of unused space.

II . Alignment is required by all modern processors.

III Alignment can help processors access data more efficiently.

a. a[0] + 4 b. a[3] c. a[4] d. the integer stored in the bytes a[4], a[5], a[6] and a[7]

7. Suppose that, using a tool such as the memory window of Visual C++, we found that a certain set of contiguous

memory locations contained the integer 0xC605CD623A8365000000. What could these memory locations hold?

I.the integer 0xC605CD623A8365000000

II. a string

III . a CPU instruction

a. I only b. III only c. I, II, and III d. I and II only

8. Immediately after the CPU executes an instruction that is neither a branch nor a jump instruction, the program

with int * a; has the value A. In a different computer, the bytes with addresses B, B+1, B+2 and B+3 also contain the