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SDP10 Final - Part I

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SDP10 Quiz sobre SDP10 Final - Part I, criado por Csse 1502 em 12-05-2018.
Csse 1502
Quiz por Csse 1502, atualizado more than 1 year ago
Csse 1502
Criado por Csse 1502 mais de 6 anos atrás
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Resumo de Recurso

Questão 1

Questão
In given two C modules which rule will Unix linker use to resolve multiple symbol definition?
Image:
1 (binary/octet-stream)
Responda
  • Multiple strong symbols are not allowed
  • None of these
  • Given multiple weak symbols, chose any of the weak symbols
  • Given a strong symbol and multiple weak symbols, choose the strong symbol.

Questão 2

Questão
Suppose we attempt to compile and link the following two C modules. Linker will generate an error?
Image:
2 (binary/octet-stream)
Responda
  • true
  • false

Questão 3

Questão
Suppose we attempt to compile and link the following two C modules. Linker will generate an error?
Image:
3 (binary/octet-stream)
Responda
  • true
  • false

Questão 4

Questão
A branch instruction
Responda
  • Sets the program counter to one of two possible values
  • Increases the program counter by a fixed amount
  • Sets the program counter to one of many possible values
  • Unconditionally sets the program counter to its operand

Questão 5

Questão
In binary, the number 1/3 is 0.01010101 . . .. In the following, assume that x is an int and y is a short. (short)((0x5555 * (int)y)>>16) and y/3 could differ even when neither computation overflows
Responda
  • True
  • False

Questão 6

Questão
A callee-saved register should be saved before it is written to in a procedure
Responda
  • True
  • False

Questão 7

Questão
In binary, the number 1/3 is 0.01010101 . . .. In the following, assume that x is an int and y is a short. For each x there exists some integer w (which may be different for different xs) such that abs(x/3 - q) < 10, where q = (((0x55555555>>w)*x)>>(32-w)).
Responda
  • false
  • true

Questão 8

Questão
In the FDEMW five-stage pipeline we analyzed in class, if we want to stall memory how many pipeline registers should be given the "stall" signal?
Responda
  • 4
  • 0
  • 5
  • 3

Questão 9

Questão
A CPU register file is a small storage device that
Responda
  • Consists of a collection of word size registers
  • Houses a critical variable for the duration of the execution of a program
  • Records the results of periodic CPU diagnostics
  • Is automatically loaded when CPU instruction refers to a word of normal memory

Questão 10

Questão
In the FDEMW five-stage pipeline we analyzed in class, if we want to stall decode how many pipeline registers should be given the “normal operation” signal?
Responda
  • 3
  • 0
  • 4
  • 5
  • 2
  • 1

Questão 11

Questão
Using a base address [Eb] %edx= 0x1000, and index register [Ei] %ecx=0x02, compute the effective address for:
Image:
1 (binary/octet-stream)
Responda
  • 0x1064
  • 0x1032
  • 0x1016
  • 0x1010

Questão 12

Questão
A memory leak is caused by a
Responda
  • Failure to free allocated memory
  • Function that allocates a large amount of memory from the heap
  • None of these
  • Bug in the memory allocator that fails to free memory

Questão 13

Questão
In the two's complement number representation, a negative number with more leading ones is larger (i.e. less negative) than a negative number with fewer leading ones.
Responda
  • true
  • false

Questão 14

Questão
When shifting a two’s complement number to the left, an overflow can only occur if the number is negative, since positive numbers have a zero in the leftmost bit
Responda
  • false
  • true

Questão 15

Questão
A program cannot accidentally use another program's memory space and "crash" a computer that uses (see the img) 1- virtual memory address 2- program relocation 3- separate instruction and data caches
Responda
  • 1 only
  • 1 and 2
  • 2
  • 1,2,3

Questão 16

Questão
In x86 assembly, the eax register can be used to hold integers but not addresses.
Responda
  • false
  • true

Questão 17

Questão
A program written directly in machine language (binary) would run faster than the same program written in assembly code and then assembled.
Responda
  • False
  • True

Questão 18

Questão
Initially byte i of memory is i + 0x20 (mod 256), %eax contains the number 3, and %ebx contains the number 5. What is in %ebx after running x86 movl (%eax), %ebx?
Responda
  • none of the above
  • 3
  • 0x25
  • 0x23

Questão 19

Questão
Adding local variables is usually used to reduce what source of inefficiency?
Responda
  • unnecessary memory references
  • condition checking overhead
  • data dependencies
  • poor branch prediction

Questão 20

Questão
Asserting a word line and asserting (to "high" voltage) a bit line writes a 1 to a DRAM cell)
Responda
  • False
  • True

Questão 21

Questão
Inline substitution (also called inlining) is usually used to reduce what source of inefficiency?
Responda
  • procedure call overhead
  • poor branch prediction
  • poor cache locality
  • unnecessary memory references

Questão 22

Questão
Using a base address [Eb] %edx=0x1000, and index register [Ei] %ecx=0x03, compute the effective address for:
Image:
1 (binary/octet-stream)
Responda
  • 0x1032
  • 0x1014
  • 0x1064
  • 0x1016

Questão 23

Questão
Jump in the following Y86-64 program. How many times does the addq instruction execute?
Image:
Image (binary/octet-stream)
Responda
  • 4
  • 3
  • 5
  • 10

Questão 24

Questão
Jump tables, such as are used for switch statements, require that the new PC be determined by a memory read. Suppose we added an assembly instruction memjump accepting a single memory address as its parameter, like memjump (%eax). In the five-stage example pipeline (F D E M W), for how many cycles will we need to bubble and/or stall stage F after executing a memjump?
Responda
  • 3
  • 4
  • 5
  • 6

Questão 25

Questão
Let f32 be the number of distinct numbers that can be represented in 4-byte IEEE-style floating point and u32 be the number of distinct numbers that can be represented as unsigned 4-byte integers. Which of the following is true?
Responda
  • f32 < u32−1
  • f32 > u32 +1
  • f32 = u32
  • f32 = u32+1

Questão 26

Questão
Let s8 be the number of distinct numbers that can be represented as signed (two's complement) 1-byte integers and u8 be the number of distinct numbers that can be represented as unsigned 1-byte integers. Which of the following is true?
Responda
  • s8 = u8
  • s8 > u8+1
  • s8 = u8 - 1
  • s8 < u8-1

Questão 27

Questão
Assume a set-associative and a direct-mapped cache both have the same address size, same data capacity, and same number of index bits. This means
Image:
в (binary/octet-stream)
Responda
  • II and III
  • .

Questão 28

Questão
Assume x is the most positive signed integer. What is x + 1?
Responda
  • none of the above
  • +∞
  • -1
  • -x

Questão 29

Questão
Logical address is calculated by: segment.base + eff_addr
Responda
  • Selector: eff_addr
  • Segment base + lin_addr
  • Selector: offset
  • Segment base + eff_addr

Questão 30

Questão
Assuming the standard IEEE-style bias, what is the smallest number of bits a float point number could have and represent the number −29/4 exactly?
Responda
  • 8
  • 4
  • 6
  • 12

Questão 31

Questão
Buses are typically designed to transfer fixed-sized chunks of bytes known as
Responda
  • words
  • frames
  • records
  • pages

Questão 32

Questão
Capacity misses are typically discussed in connection with?
Responda
  • fully-associative cache
  • direct-mapped caches
  • set-associative caches
  • all of the above

Questão 33

Questão
Check the following (listed in alphabetical order) in order of importance when optimizing code that operates on very large arrays: B = Body of loop optimization (function inlining, efficient math), C = Cache locality, O = big-O of algorithm used
Responda
  • BCO
  • OBC
  • BOC
  • COB

Questão 34

Questão
Compare the size of int and int*
Responda
  • each one of the above depends on the compute
  • int has fewer bits
  • int* has fewer bits
  • they have the same number of bit

Questão 35

Questão
Loop blocking is usually used to reduce what source of inefficiency?
Responda
  • poor cache locality
  • data dependencies
  • poor branch prediction
  • procedure call overhead

Questão 36

Questão
Loop unrolling is usually used to remove what source of inefficiency?
Responda
  • poor cache locality
  • data dependencies
  • poor branch prediction
  • procedure call overhead

Questão 37

Questão
Programs with good ______ ______, tend to access a referenced memory location multiple times in the near future.
Responda
  • Temporal locality
  • Spatial locality
  • Repetitive locality
  • Associative locality

Questão 38

Questão
Putting \#include "foo.h" in your C file is the equivalent of typing the contents of foo.h into your file
Responda
  • true
  • false

Questão 39

Questão
Consider the following code fragment
Image:
Q (binary/octet-stream)
Responda
  • The value of &y is closer to the value of &x than to the value &a
  • The value of *y is closer to the value of *x than to the value *a
  • The value of *a and *b are closer to each other than the values of *x and *y
  • The value of &a and &b are closer to each other than the values of &x and &y

Questão 40

Questão
Compared to dynamic RAM (SRAM), dynamic RAM (DRAM) is
Responda
  • a) DRAM is cheaper than SRAM
  • b) DRAM is faster than SRAM
  • c) DRAM is more likely to be used for main memory than for on-chip caches
  • d) SRAM is more likely to be used for main memory than for on-chip cache
  • a) DRAM uses more transistors per bit than SRAM
  • b) DRAM uses a capacitor to store a value
  • c) Typically a computer has more DRAM than SRA

Questão 41

Questão
Compiling C into x86 assembly comprises translating each C statement into a single assembly instruction.
Responda
  • False
  • True

Questão 42

Questão
Conflict misses are typically discussed in connection with?
Responda
  • direct-mapped caches
  • set-associative caches
  • fully-associative caches
  • all of the above

Questão 43

Questão
Rank the following in order of significance when writing code that deals with large arrays: - Algorithmic efficiency (i.e., big-O), - Computational efficiency (e.g., loop unrolling, inlining, etc), - L cache Locality.
Responda
  • ACL
  • ALC
  • LCA
  • CAL

Questão 44

Questão
CPE (cycles per element, also called cycles per execution or cycles per instruction in other sources). If we have code with 20 CPE and run it on a problem where my algorithm executes on 100 elements; I should expect the runtime to be
Responda
  • 50-220 cycles
  • 0-50 cycles
  • 220-1100 cycles
  • 1100-2200 cycles

Questão 45

Questão
Reassociation of operators is usually used to reduce what source of inefficiency?
Responda
  • data dependencies
  • condition checking overhead
  • poor branch prediction
  • poor cache locality

Questão 46

Questão
Register %edx is one of the "callee-save" registers. This means that if procedure baz calls procedure xyxxy
Responda
  • baz may assume xyxxy did not change %edx
  • xyxxy may communicate with baz through register %edx
  • baz must assume xyxxy could have changed %edx
  • baz may communicate with xyxxy through register %edx

Questão 47

Questão
Register %esi is one of the "caller-save" registers. This means that if procedure baz calls procedure xyxxy
Responda
  • baz must assume xyxxy could have changed %esi
  • xyxxy may communicate with baz through register %esi
  • baz may assume xyxxy did not change %esi
  • baz may communicate with xyxxy through register %esi

Questão 48

Questão
Dirty bits are associated with (pick the best answer)
Responda
  • write-back caches
  • write-through caches
  • set-associative caches
  • direct-mapped caches

Questão 49

Questão
Edsger Dijkstra wrote "Go To Statement Considered Harmful" in 1968 in which he argued (translated into current language) that code that uses goto becomes needlessly hard to read and maintain compared to only using if and while. In assembly, we use the goto-like jump instructions extensively; the main reason for this is?
Responda
  • goto is only bad when mixed with higher-level constructs
  • Dijkstra was wrong
  • no one is reading assembly anyway
  • there is no other alternative in assembly

Questão 50

Questão
Every procedure in an x86 assembly program must be declared using .globl
Responda
  • False
  • True

Questão 51

Questão
Which of the following is a good reason (are good reasons) to equip the CPU with small amounts of fast memory? I. To make the design of the compiler simpler II. To make some CPU instructions smaller III. To make some CPU instructions faster
Responda
  • III only
  • II and III only
  • I, II, and III
  • II only

Questão 52

Questão
Given 6-bit numbers where 010001 + 001010 = 010110, which of the following describes the number representation used?
Responda
  • floating-point with 2 exponent bits
  • floating-point with 3 exponent bits
  • integer
  • floating-point with 4 exponent bits

Questão 53

Questão
Given 6-bit numbers where 010101 + 000001 = 010110, which of the following describes the number representation used?
Responda
  • integer
  • floating-point with 3 exponent bits
  • floating-point with 1 exponent bits
  • floating-point with 2 exponent bits

Questão 54

Questão
Good software design includes writing procedures for code you might otherwise repeat in-line. Pulling code into procedures can help some branch predictors; how else can it improve your program’s performance and/or your compiler’s ability to optimize your code?
Responda
  • more opportunities for loop unrolling
  • less chance of compiler having to worry about aliasing and side effects
  • more opportunities for pipeline-level parallelism
  • better instruction cache hit rate

Questão 55

Questão
Return from function issues a bubble in pipeline.
Responda
  • true
  • false

Questão 56

Questão
Good software design includes writing procedures for code you might otherwise repeat in-line. Pulling code into procedures involves call/return overhead; how else can it hurt your program's performance and/or your compiler's ability to optimize your code?
Responda
  • more chance of compiler having to worry about aliasing and side effects
  • fewer opportunities for pipeline-level parallelism
  • worse instruction cache hit rate
  • fewer opportunities for loop unrolling

Questão 57

Questão
SRAM is "static" in the sense that if the power is turned off, SRAM will continue to store data (e.g. as in flash memory in MP3 players or USB thumb drives).
Responda
  • false
  • true

Questão 58

Questão
Suppose addresses A and B have different tags but the same index (for those caches that have tags and indexes, that is). Assume the cache is empty prior to the accesses listed in the questions. In the access pattern "read A, then read B, then read A, then read B" the second read of A will be a miss for?
Responda
  • a direct-mapped cache
  • a set-associative cache
  • a fully-associative cache
  • all of the above

Questão 59

Questão
How does knowing you have a pipelined processor change the code you write?
Responda
  • it suggests optimizations like multiple accumulators
  • it suggests optimizations like adding local variables
  • it suggests optimizations like loop unrolling
  • it suggests optimizations like loop reordering

Questão 60

Questão
Suppose addresses A and B have different tags but the same index (for those caches that have tags and indexes, that is). Assume the cache is empty prior to the accesses listed in the questions. In the access pattern "read A, then read B" the read of B will be a miss for
Responda
  • all of the above
  • a fully-associative cache
  • a direct-mapped cache
  • a set-associative cache

Questão 61

Questão
How is "-1" (decimal) represented in an 8-bit 2's complement binary format?
Responda
  • 11111111
  • .

Questão 62

Questão
Suppose page table entries are 8 bytes long and virtual addresses are 32 bytes long. If each page table is to fit on a single page, what is the smallest pages can be if we have a 2-level page table hierarchy?
Responda
  • bigger than any of the above options
  • 2 KB
  • 512 B
  • smaller than any of the above options

Questão 63

Questão
How is 46 (decimal) represented in an 8-bit 2's complement binary format?
Responda
  • 00101100
  • 00101110
  • 00011110
  • 01000110

Questão 64

Questão
How is -10 (decimal) represented in an 8-bit 2's complement binary format?
Responda
  • 11110110
  • 10001010
  • 11110101
  • 11111010

Questão 65

Questão
Which of the following move operations is the following instruction an example of movl (%edx), (%eax)?
Responda
  • error, can’t move memory to memory
  • memory to immediate
  • register to memory
  • memory to register

Questão 66

Questão
In the access pattern “write A, then write B, then write A”, to minimize writes to the higher-level cache we should pick which of the following?
Responda
  • a write-through fully-associative cache
  • a write-back fully-associative cache
  • a write-through direct-mapped cache
  • a write-back direct-mapped cache
  • two or more of the above are equivalently the best option

Questão 67

Questão
How many hex digits are needed to represent the decimal number 67?
Responda
  • 2
  • 6
  • 4
  • 7

Questão 68

Questão
How many ints fit inside x if x is declared as int *x = malloc(8); ? Word size is 4.
Responda
  • 2
  • 1
  • 8
  • 0

Questão 69

Questão
Which of the following move operations is the following instruction an example of movl (%edx), %eax?
Responda
  • error, can’t move memory to memory
  • memory to register
  • register to memory
  • memory to immediate

Questão 70

Questão
How many rules do Unix linkers use for dealing with multiply defined symbol
Responda
  • 3
  • 4
  • 5
  • 2

Questão 71

Questão
Suppose an array of char (8-bit values) {0x12, 0x34, 0x56, 0x78} is stored at address 0x24 of a little-endian computer. What byte is stored at address 0x26?
Responda
  • 0x56
  • 0x00
  • 0x65
  • A known value not listed here

Questão 72

Questão
If a computer has 8GB memory, a single 1MB cache, and 4KB of registers, the total amount of data it can store is?
Responda
  • more than 8GB but less than 8GB + 1MB
  • more than 8GB + 1MB but less than 8GB + 1MB + 1KB
  • more than 8GB + 1MB + 4KB
  • 8GB + 1MB + 4KB

Questão 73

Questão
Suppose the 32-bit value 0x12345678 is stored at address 0x24 of a big-endian computer. What byte is stored at address 0x23?
Responda
  • 0x65
  • 0x34
  • 0x43
  • A known value not listed here
  • An unknown value because the number does not overlap address 0x25

Questão 74

Questão
When the following code fragment is executed on a computer with 32-bit integers and a fully-associative cache with 16-byte cache lines, how many bytes of the array A[] will be fetched into the cache from main memory
Image:
Q (binary/octet-stream)
Responda
  • At most 96
  • Exactly 17
  • Exactly 32
  • At most 80

Questão 75

Questão
If a wire carries a logical value of 0, its voltage level will be 0 Volts.
Responda
  • False
  • True

Questão 76

Questão
If we fail to find data in a cache because we have never accessed the data before, we call that a
Responda
  • cold miss
  • capacity miss
  • conflict miss
  • forced miss

Questão 77

Questão
If we fail to find data in a cache because we've read too much data since we last accessed that same data, we call that a
Responda
  • capacity miss
  • cold miss
  • conflict miss
  • forced miss

Questão 78

Questão
Suppose the 32-bit value 0x12345678 is stored at address 0x24 of a big-endian computer. What byte is stored at address 0x25?
Responda
  • 0x56
  • A known value not listed here
  • 0x65
  • 0x43
  • An unknown value because the number does not overlap address 0x25
  • F 0x34

Questão 79

Questão
If we were running a non-pipelined processor (like SEQ) with a real memory system, which of the following optimization strategies would no longer provide a speed benefit?
Responda
  • using multiple accumulators
  • adding local variables
  • function call inlining
  • none of the above would provide a speed benefit

Questão 80

Questão
The .data section of an x86 assembly program is used to specify the parameters for each procedure.
Responda
  • false
  • true

Questão 81

Questão
In C, a pointer variable is used for storing an address
Responda
  • True
  • False

Questão 82

Questão
If x is the most negative signed integer, what is -x?
Responda
  • the most negative signed number
  • one
  • the most positive signed number
  • negative one

Questão 83

Questão
In a DRAM, all cells have to be periodically refreshed, not just the ones that have been read.
Responda
  • True
  • False

Questão 84

Questão
In a program with good ____________, if a memory location is referenced once, then the program is likely to access nearby memory locations in the near future
Responda
  • Spatial locality
  • Temporal locality
  • Repetitive locality
  • Associative locality

Questão 85

Questão
The ASCII code for the character 'B' is 0x42. What is the ASCII hex code for the character 'D'?
Responda
  • 0x4B
  • 0x5A
  • 0x48
  • 0x44

Questão 86

Questão
If we were running a non-pipelined processor (like SEQ) with a real memory system, which of the following optimization strategies would not longer provide a speed benefit?
Responda
  • none of the above would provide a speed benefit
  • adding local variables
  • using multiple accumulators
  • function call inlining

Questão 87

Questão
In C, local variables allocated inside functions are allocated:
Responda
  • On the stack
  • In static storage
  • In virtual memory
  • In the heap

Questão 88

Questão
In C, using default floating point settings, a special value of "infinity" is computed when
Responda
  • A floating-point computation results in an overflow
  • Program execution is halted
  • An erroneous value is computed and execution continues
  • An exception is raised

Questão 89

Questão
The ASCII code for the character 'B' is 0x42. What is the ASCII hex code for the character ‘E’?
Responda
  • 0x45
  • 0x48
  • 0x56

Questão 90

Questão
In given two C modules which rule will Unix linker use to resolve multiple symbol definition?
Image:
вв (binary/octet-stream)
Responda
  • Given a strong symbol and multiple weak symbols, choose the strong symbol.
  • Given multiple weak symbols, chose any of the weak symbols
  • Multiple strong symbols are not allowed.
  • None of these

Questão 91

Questão
The assembly instruction int x used to make system calls only accepts a 1-byte (256-value) argument x, but Linux uses it to support over 300 system calls. How does it do that?
Responda
  • SRAM would lose its data, DRAM would keep its data
  • SRAM would keep its data, DRAM would keep its data
  • SRAM would keep its data, DRAM would lose its data
  • SRAM would lose its data, DRAM would lose its data

Questão 92

Questão
The contents of how many program registers are modified by an assembly push operation?
Responda
  • 1
  • 2
  • 3 or more
  • it depends on that argument of the push

Questão 93

Questão
The difference between the SAR (arithmetic shift right) and SHR (logical shift right) operations is that SAR puts a one into the leftmost bit after a shift and SHR puts a zero.
Responda
  • false
  • true

Questão 94

Questão
The EBP is a callee-saved register.
Responda
  • true
  • false

Questão 95

Questão
The EFLAGS register contains the zero flag and the sign flag?
Responda
  • true
  • false

Questão 96

Questão
What is the value of the following C expression? x=0x1234 and y=0x3 ((x >> y) << y)
Responda
  • 0x1230
  • 0x1234
  • 0x0246
  • 0x1200

Questão 97

Questão
The hardware is aware of the program stack
Responda
  • true
  • false

Questão 98

Questão
The instruction addq %rax, %rbx changes what?
Responda
  • The contents of the rbx register
  • The contents of memory at an address found in the rax register
  • The contents of memory at an address found in the rbx register
  • The contents of the rax register

Questão 99

Questão
What is the value of the following C expression? x=0x00 and y=0xA5 x && ~y
Responda
  • 0xFF50
  • 0x0000
  • 0x0001
  • 0x11A5

Questão 100

Questão
The instruction cmp eax,ebx (or cmp %ebx,%eax in AT&T syntax) computes the value of EAX - EBX.
Responda
  • true
  • false

Questão 101

Questão
_______ - program transformation that reduces the number of iterations for a loop by increasing the number of elements computed on each iteration
Responda
  • Loop unrolling
  • Memory aliasing
  • Side effect
  • Code motion

Questão 102

Questão
The valid bit is associated with
Responda
  • fully-associative caches
  • write-through caches
  • set-associative caches
  • direct-mapped caches

Questão 103

Questão
It is possible to explicitly specify the number of threads to be created in the team, using the _____ attribute:
Responda
  • pragma omp
  • parallel
  • private
  • Num_threads

Questão 104

Questão
CPU optimized for throughput
Responda
  • True
  • False

Questão 105

Questão
The working set of a program is formed by
Responda
  • The pages that the program is actively using
  • The libraries required by the program
  • The memory of the program that is currently in physical memory
  • All the files the program needs to execute

Questão 106

Questão
This problem occurs when a larger type is converted into a smaller type or with the signed-unsigned operations?
Responda
  • truncation
  • overflow

Questão 107

Questão
Using multiple accumulators is usually used to reduce what source of inefficiency?
Responda
  • unnecessary memory references
  • condition checking overhead
  • data dependencies
  • poor branch prediction

Questão 108

Questão
169. In C a single statement that performs the equivalent of y=x*100; but without using the multiply operator (*);
Responda
  • y = (x>>6)+(x<<5)+(x<<2)
  • y = (x<<6)+(x<<3)+(x>>2)
  • y = (x<<5)+(x<<5)+(x<<7)
  • y = (x<<6)+(x<<5)+(x<<2)

Questão 109

Questão
We can encode the C command a ? b : c, where all three variables are of type int,
Responda
  • ((-!!a) & b) | ((-!a) & c)
  • ((!!a) &amp; b) | ((!a) &amp; c)
  • Any of the above
  • (a &amp; b) | ((!a) &amp; c)

Questão 110

Questão
We say that pipelining generally increases latency. That statement means (select all that are part of the definition of "increases latency")
Responda
  • each instruction takes more time to complete
  • each instruction takes less time to complete
  • entire programs take more time to complete
  • entire programs take less time to complete

Questão 111

Questão
Two computers A and B with a cache in the CPU chip differ only in that A has an L2 cache and B does not. Which of the following are possible?
Image:
Q (binary/octet-stream)
Responda
  • 1 & 2 only
  • 2 & 3 only
  • 1 only
  • 2

Questão 112

Questão
At which of the following times is a stack frame created?
Image:
Q (binary/octet-stream)
Responda
  • II and III only
  • II only
  • III only
  • I and II only

Questão 113

Questão
The bitwise and operation (& in C) can be used to flip the bits of a word
Responda
  • true
  • false

Questão 114

Questão
Linking can be performed at
Responda
  • run time
  • compile time
  • all of the above
  • load time

Questão 115

Questão
Parallel processing mechanisms to achieve parallelism in uniprocessor system are:
Responda
  • All of the above
  • Multiple function units
  • Parallelism and pipelining within CPU
  • Multiprogramming and time sharing

Questão 116

Questão
This is an example of?
Image:
Q (binary/octet-stream)
Responda
  • Hybrid system
  • shared memory UMA
  • Distributed memory architecture
  • Shared memory NUMA

Questão 117

Questão
This is an example of?
Image:
Q (binary/octet-stream)
Responda
  • None
  • Loop unrolling
  • Loop fusion
  • Loop fission

Questão 118

Questão
This is an example of?
Image:
Q (binary/octet-stream)
Responda
  • MIMD
  • MISD
  • SIMD
  • SISD

Questão 119

Questão
This is an example of?
Image:
й (binary/octet-stream)
Responda
  • MIMD
  • MISD
  • SIMD
  • SISD

Questão 120

Questão
This is an example of?
Image:
ц (binary/octet-stream)
Responda
  • MIMD
  • MISD
  • SIMD
  • SISD

Questão 121

Questão
This is an example of?
Image:
у (binary/octet-stream)
Responda
  • MIMD
  • MISD
  • SIMD
  • SISD

Questão 122

Questão
The _______ directive causes threads encountering the barrier to wait until all the other threads in the same team have encountered the barrier.
Responda
  • single
  • barrier
  • nowait
  • private

Questão 123

Questão
How is 148 (decimal) represented in a 16-bit 2’s complement binary format?
Responda
  • 0000 0000 1101 0111
  • 0000 0000 0010 1001
  • 1111 1111 0010 1000
  • 1111 1111 0110 1100

Questão 124

Questão
In a Compare the runtime of y = x * 5 and y = (x<<2) + x, measured by the time it takes for the resulting value of y to be available somewhere in the pipeline.
Responda
  • y = x * 5 is faster
  • y = (x<<2) + 5 is faster
  • not given
  • they take the same number of cycles

Questão 125

Questão
What is the difference between 15 and $15?
Responda
  • 15 is an address, $15 is a value
  • 15 is a value, $15 is an address
  • 15 is legal in assembly, $15 is not
  • $15 is legal in assembly, 15 is not

Questão 126

Questão
What is the result of the following assembly code instruction?
Image:
Image (binary/octet-stream)
Responda
  • Fetch the data from register %ecx and store in register %eax
  • Fetch the data from the register %ecx and store in the memory address indicated by (%eax)
  • Fetch the data from the register %eax and store in register %ecx
  • Fetch the data from the memory address indicated by (%eax) and store in the register %ecx

Questão 127

Questão
What is the value of the following C expression? x=0xA0 and y=0x0F ~x||~y
Responda
  • 0х0001
  • 0х6000
  • 0xFF50
  • 0xFFFF

Questão 128

Questão
What value ends up in EAX afer the following code is executed?
Image:
Image (binary/octet-stream)
Responda
  • 48 (decimal) or 00110000 (binary) or 0x30 (hex)
  • 50 (decimal) or 00110010 (binary) or 0x32 (hex)
  • 46 (decimal) or 00101110 (binary) or 0x2E (hex)
  • 52 (decimal) or 00110100 (binary) or 0x34 (hex)

Questão 129

Questão
When shifting a two's complement number to the left, an overflow can only occur if the number is negative, since positive numbers have a zero in the leftmost bit.
Responda
  • True
  • False

Questão 130

Questão
Which of the five phases determines how many bytes long an instruction is?
Responda
  • Fetch
  • Decode
  • Writeback
  • Execute

Questão 131

Questão
Which of the five phases determines what the next PC is?
Responda
  • Fetch
  • Memory
  • Execute
  • Decode

Questão 132

Questão
Which of the five phases determines the destination register for instructions that write to registers?
Responda
  • Decode
  • Writeback
  • Fetch
  • Execute

Questão 133

Questão
Which of the following computations may be performed by exactly one CPU instruction? (img) a = 5; a = b + c * 5; for (i = 0; i < 10; i += a[i++]);
Responda
  • I, II, and III
  • II only
  • I and II only
  • I only

Questão 134

Questão
Which of the following is true?
Responda
  • A direct-mapped cache is a set-associative cache with set size 1
  • A direct-mapped cache is a fully-associative cache with only one set
  • A direct-mapped cache is a fully-associative cache with set size 1
  • A direct-mapped cache is a set-associative cache with only one set

Questão 135

Questão
Which of the following manages the transfer of data between the cache and main memory
Responda
  • Operating system
  • Compiler
  • Hardware
  • Registry

Questão 136

Questão
Which of the following manages the transfer of data between the CPU registers and the cache
Responda
  • Operating system
  • Compiler
  • Hardware
  • Registry

Questão 137

Questão
Which of the following registers is the lower order 16 bit register of register %ecx?
Responda
  • %cx
  • %cl
  • %ch
  • %cy

Questão 138

Questão
Which of the following statements about alignment within C struct's is true?
Responda
  • A constant offset associated with the member is added to the address
  • The struct consists of an array of pointers to the elements of the struct
  • The element name is looked up in a symbol table
  • A linear search is made from the base address of the struct

Questão 139

Questão
Which of the following statements about floating-point numbers in C is true?
Image:
Image (binary/octet-stream)
Responda
  • II only
  • III only
  • I
  • I and II

Questão 140

Questão
Which one of the following IA32 registers is typically used for stack management?
Responda
  • %esp
  • %eax
  • %ebx
  • %edi

Questão 141

Questão
Which one of the following optimizations does not provide any speed benefit for a non-pipelined processor, such as SEQ?
Responda
  • Storing reused computed values in variables instead of recomputing them
  • Invocation inlining
  • Using more efficient algorithms
  • Reassociation

Questão 142

Questão
Which of the following levels of a typical memory hierarchy transfers data in chunks of smallest size?
Responda
  • Main memory < ---> disk
  • Cache < ---> main memory
  • They all transfer one byte at a time
  • CPU registers < ---> cache

Questão 143

Questão
In C, a pointer variable is used for storing an address
Responda
  • True
  • False

Questão 144

Questão
If we cut power for one millisecond, which of the following is true?
Responda
  • SRAM would keep its data, DRAM would lose its data
  • SRAM would lose its data, DRAM would keep its data
  • SRAM would lose its data, DRAM would lose its data
  • SRAM would keep its data, DRAM would keep its data

Questão 145

Questão
If we cut power for one minute, which of the following is true?
Responda
  • SRAM would lose its data, DRAM would lose its data
  • SRAM would lose its data, DRAM would keep its data
  • SRAM would keep its data, DRAM would keep its data
  • SRAM would keep its data, DRAM would lose its data

Questão 146

Questão
Select the most correct statement from the following as applied over the last two decades:
Responda
  • Processors get faster but memory does not
  • Processors and memory both get faster, but memory gets faster faster that processors do
  • Processors and memory both get faster, but processors get faster than memory does
  • Memory gets faster but processor does not

Questão 147

Questão
Which one of the following optimizations does not provide any speed benefit for a non-pipelined processor, such as SEQ?
Responda
  • Using more efficient algorithms
  • Invocation inlining
  • Reassociation
  • Storing reused, computed values in variables instead of recomputing them

Questão 148

Questão
Consider the following code. Assume the compiler is performing no optimization. Which of the following strategies would improve the speed of this code the most in the case where it returns true?
Image:
Image (binary/octet-stream)
Responda
  • Unroll the loop
  • Pull the (x % i)==0 into a function isDivisibleBy
  • Declare int sx = (int)sqrt(x) and change i < sqrt(x) to i < sx
  • Move the check for (x % 2) != 0 to before the loop

Questão 149

Questão
Consider the following code. This code would most likely benefit from which of the following optimization strategies
Image:
Image (binary/octet-stream)
Responda
  • Using multiple accumulators
  • Improving cache locality
  • Loop unrolling
  • Adding local variables

Questão 150

Questão
What does the following C code print?
Image:
Image (binary/octet-stream)
Responda
  • P = 103, c = 101
  • P = 104, c = 101
  • P = 105, c = 103
  • P = 104, c = 102

Questão 151

Questão
The bitwise and operation (& in C) can be used to flip the bits of a word
Responda
  • True
  • False

Questão 152

Questão
The bitwise xor operation (^ in C) can be used to flip the bits of a word
Responda
  • True
  • False

Questão 153

Questão
Consider a direct-mapped cache with 256 sets and 16 byte blocks. In this cache the address 0x12345 maps to the same set as which of the following addresses?
Responda
  • 0x02345
  • 0x22244
  • 0x12040
  • 0x12354

Questão 154

Questão
In C, on a 34-bit x86 machine, the expression (1 << 31) results in a negative integer
Responda
  • True
  • False

Questão 155

Questão
Consider the following code. Which of the following changes would make the largest positive impact on its cache locality?
Image:
Image (binary/octet-stream)
Responda
  • Put the for-i loop inside of the for-j loop instead of the other way around
  • Store the result of (i*101)%n outside the inner loop
  • Block the accesses by nesting three or four for loops instead of just two
  • Change int** to int*

Questão 156

Questão
Consider the following code. Assume the compiler is performing no optimizations and that isPrime is the exact code presented in another question on this exam. Which of the following strategies would improve the speed of this code the most?
Image:
Image (binary/octet-stream)
Responda
  • Inline the isPrime call
  • Add a second ans accumulator
  • Swap the order of the if statements
  • Change the nested if statements to a single if with a &&

Questão 157

Questão
Consider the following two versions of a C function: (Assume len is larger than 10)
Image:
Image (binary/octet-stream)
Responda
  • sum1
  • None of them
  • sum2
  • Both of them

Questão 158

Questão
Which of the following is necessary true regarding the following code fragment?
Image:
Image (binary/octet-stream)
Responda
  • It exhibits locality of reference but only when a == b
  • It exhibits locality of reference because the variables are allocated near each other
  • It exhibit no locality of reference
  • It exhibits locality of reference no matter where the variables are allocated

Questão 159

Questão
A & B is the bitwise version of A && B; A | B is the bitwise version of A || B; which of the following is the bitwise version of A == B?
Responda
  • ~(a = b)
  • a = b
  • ~ (a ^ b)
  • a ^ b

Questão 160

Questão
The unary & operator returns (in C language)
Responda
  • The logical “and” of two integer operands
  • The logical “or” of two integer operands
  • The value of a data object
  • The address of a data object

Questão 161

Questão
In C a single statement that performs the equivalent of y = x *100, but without using the multiply operator (*)
Responda
  • y = (x<<6) + (x<<5) + (x<<2)
  • y = (x>>6) + (x<<5) + (x<<2)
  • y = (x<<6) + (x<<3) + (x>>2)
  • y = (x<<5) + (x<<5) + (x<<7)

Questão 162

Questão
Adding local variable is usually used to reduce what source inefficiency?
Responda
  • Condition checking overhead
  • Poor branch prediction
  • Unnecessary memory references
  • Data dependencies

Questão 163

Questão
If, in C, an array is declared by “int a[10];”, then accessing a[11] during execution will generate an error message.
Responda
  • True
  • False

Questão 164

Questão
In C, if x is an integer variable, the expression “x << 3” computes x * 8 but does not change the value of x.
Responda
  • True
  • False

Questão 165

Questão
Which of the following code snippets is fastest? Assume n is very large (more than ten thousand).
Responda
  • for(i=0;i<n;i+=1) for(j=0;j<n;j+=1) a[i][j] = b[j][i];
  • for(j=0;j<n;j+=1) for(i=0;i<n;i+=1) a[i][j] = b[j][i];
  • Image:
    Image (binary/octet-stream)
  • two or more of the above are equivalently the fastest

Questão 166

Questão
Which of the following code snippets is fastest? Assume n is very large (more than ten thousand).
Responda
  • a) for(k=0; k<n; k+=16) for(l=0; l<n; l+=16) for(j=0;j<16;j+=1) for(i=0;i<16;i+=1) a[i+l][j+k] = b[i+l][j+k];
  • for(i=0;i<n;i+=1) for(j=0;j<n;j+=1) a[i][j] = b[i][j];
  • for(j=0;j<n;j+=1) for(i=0;i<n;i+=1) a[i][j] = b[i][j];
  • two or more of the above are equivalently the fastest

Questão 167

Questão
In binary, the number 1/3 is 0.01010101 . . .. In the following, assume that x is an int and y is a short. (short)((0x5555 * (int)y)>>16) and y/3 could differ because of overflow
Responda
  • True
  • False

Questão 168

Questão
How is 148 (decimal) represented in a 16-bit 2’s complement binary format?
Responda
  • 0000 0000 1101 0111
  • 0000 0000 0010 1001
  • 1111 1111 0010 1000
  • 1111 1111 0110 1100

Questão 169

Questão
Which of the following code snippets is fastest? Assume n is very large (more than ten thousand).
Responda
  • for(j=0;j...
  • for(i=0;i...
  • two or more of the above are equivalently the fastest
  • for(k=0;k<n;k+=16) for(l=0;l<n;l+=16)...

Questão 170

Questão
In a Compare the runtime of y = x * 5 and y = (x<<2) + x, measured by the time it takes for the resulting value of y to be available somewhere in the pipeline.
Responda
  • y = x * 5 is faster
  • they take the same number of cycles
  • not given
  • y = (x<<2) + 5 is faster

Questão 171

Questão
The program counter contains:
Responda
  • The address of the CPU instruction that is about to be executed
  • The number of programs currently running
  • The number of CPU instructions a program has executed so far
  • The number of processes currently running

Questão 172

Questão
A memory leak is caused by a:
Responda
  • Bug in the memory allocator that fails to free memory
  • Failure to free allocated memory
  • None of these
  • Function that allocates a large amount of memory from the heap

Questão 173

Questão
Registers and cache memory are the same thing
Responda
  • False
  • True

Questão 174

Questão
In a computer in which both addresses and integers are 32 bits wide, how many bytes of memory will the compiler allocate for the following code fragment?
Image:
2018 05 13 131017 (binary/octet-stream)
Responda
  • 32
  • 8
  • 16
  • 4

Questão 175

Questão
In C, local variables allocated inside functions are allocated:
Responda
  • On the stack
  • In the heap
  • In virtual memory
  • In static storage

Questão 176

Questão
What is the value of the following C expression? x=0xA0 and y=0x0F ~x || ~y
Responda
  • 0x0000
  • 0xFF50
  • 0xFFFF
  • 0x0001

Questão 177

Questão
What is an example of?
Image:
2018 05 13 131348 (binary/octet-stream)
Responda
  • Loop unrolling
  • Loop fission
  • none
  • Loop fusion

Questão 178

Questão
How is 215 (decimal) represented in a 16-bit 2's complement binary format?
Responda
  • 1111 1111 0010 1001
  • 0000 0000 1101 0111
  • 0000 0000 0010 1001
  • 1111 1111 0010 1000

Questão 179

Questão
This code indicates that Work2 and Work3 must be run in _______ :
Image:
2018 05 13 131712 (binary/octet-stream)
Responda
  • none
  • parallel
  • sequence
  • both

Questão 180

Questão
____ involve identifying a computation that is performed multiple times (e.g., within a loop), but such that the result of the computation will not change.
Responda
  • Code motion
  • Side effect
  • Loop unrolling
  • Memory aliasing

Questão 181

Questão
In C, for the expression (x | THE_MASK), where THE_MASK has at least one bit that is not zero, the result will be zero if all the bits of x are zero.
Responda
  • True
  • False

Questão 182

Questão
What is the value of the following C expression? x = 0x128 and y = 0x2 ~x << y (in hex)
Responda
  • 0x000004A0
  • 0x000FFB5C
  • 0xFFFFFB5C
  • 0x00FF04A0

Questão 183

Questão
In C, using default floating point settings, a special value of "infinity" is computed when:
Responda
  • A floating-point computation results in an overflow
  • Program execution is halted
  • An exception is raised
  • An erroneous value is computed and execution continues

Questão 184

Questão
GPU optimized for latency.
Responda
  • true
  • false

Questão 185

Questão
If you don’t explicitly specify the number of threads (OpenMP) how many thread will be executed?
Responda
  • 1
  • Depends on the number of cores on computer
  • 2
  • 4

Questão 186

Questão
CPU optimized for latency
Responda
  • true
  • false

Questão 187

Questão
Program take as input a collection of relocatable object files and command-line arguments and generate as output a fully linked executable object file that can be loaded and run:
Responda
  • Static linker
  • Dynamic linker
  • Both
  • none

Questão 188

Questão
If we find the data we want in a cache, we call that a
Responda
  • Cache find
  • Cache hit
  • Cache miss
  • Cache success

Questão 189

Questão
The___construct forms a region that contains one or more structured blocks. Each block of a_____ directive executed once by one of the threads (any one) in the team?
Responda
  • parallel
  • master
  • section
  • schedule

Questão 190

Questão
Pick a value for A and for B which will cause the two procedures below to return different results.
Image:
2018 05 13 132528 (binary/octet-stream)
Responda
  • a=7; b=1;
  • a=1; b=2;
  • a=1; b=5;
  • a=1; b=1;

Questão 191

Questão
Pick a value for A and for B which will cause the two procedures below to return the same results.
Image:
2018 05 13 132636 (binary/octet-stream)
Responda
  • ОДИНАКОВЫЕ ВОЗВРАЩАЮТ: (7,1) (1,5) (1,1)
  • нет других вариантов

Questão 192

Questão
A is the 4-bit value 0011 and B is the 4-bit value 0110. What is A^B?
Responda
  • 0011
  • 1110
  • 0111
  • 0101

Questão 193

Questão
Consider the following code. This code would most likely benefit from which of the following optimization strategies.
Image:
2018 05 13 133034 (binary/octet-stream)
Responda
  • improving locality
  • loop unrolling
  • using multiple
  • adding local variables

Questão 194

Questão
Conflict misses are typically discussed in connection with?
Responda
  • all of the above
  • fully-associative caches
  • set-associative caches
  • direct-mapped caches

Questão 195

Questão
What is -5 as a six bit two’s complement number? Answer in binary
Responda
  • 101111
  • 111011
  • 000001
  • 011011

Questão 196

Questão
By default, OpenMp _____ assigns loop iterations to threads. When the parallel for block is entered, it assigns each thread the set of loop iterations it is to execute?
Responda
  • static
  • runtime
  • dynamic
  • auto

Questão 197

Questão
In general, which of the following is slowest?
Responda
  • moving from one register to another
  • doing division
  • accessing memory
  • comparing two numbers to decide where to jump

Questão 198

Questão
How is 28 (decimal) represented in an 8-bit 2’s complement binary format?
Responda
  • 0001 1100
  • 1110 0100
  • 1100 1011
  • 1110 0011

Questão 199

Questão
The ASCII code for the character ‘b’ is 98. How can the character ‘b’ be represented in binary using ASCII codes?
Responda
  • 1011 1111
  • 1010 1111
  • 0110 0010
  • 1000 0001

Questão 200

Questão
This code indicates that any of the tasks Work1, Work2 + Work3 and Work4 may run in _____________:
Image:
2018 05 13 133639 (binary/octet-stream)
Responda
  • parallel
  • sequence
  • both
  • none

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