C2450 Test 2 - Ch. 4

Front 1

What is an immediate operand?

Back 1

a constant value or the result of a constant expression.

Front 2

What is a register operand?

Back 2

refers to data stored in registers. The register name is converted to a number and encoded within the instruction

Front 3

What is a memory operand?

Back 3

a reference to a location in memory. The memory address is encoded within the instruction, or a register holds the address of a memory location

Front 4

What is a direct operand?

Back 4

a named reference to storage in memory (a fixed memory location)

Front 5

What is the syntax of a MOV instruction?

Back 5

mov destination, source

Front 6

In a MOV instruction, how many memory operands are permitted?

Back 6

one

Front 7

In a MOV instruction, can the operands be different sizes?

Back 7

no

Front 8

T or F:
The following is a permitted MOV instruction.
mov eip, count

Back 8

FALSE
EIP is not a valid destination register

Front 9

T or F:
The following is a permitted MOV instruction
.mov 56, count

Back 9

FALSE an immediate operand cannot be a destination

Front 10

T or F
:the MOVZX instruction, the destination must be a register.

Back 10

TRUE

Front 11

T or F:
The MOVZX instruction permits the source and destination to be different sizes.

Back 11

TRUE
the destination must be equal to or larger than the source

Front 12

When you copy a smaller value into a larger destination, the MOVZX instruction fills the upper half of the destination with _____ .

Back 12

0s

Front 13

T or F:
A signed value can be the source when using a MOVZX instruction.

Back 13

FALSE
the source must be unsigned, and the destination must be a register

Front 14

What is the difference between MOVZX and MOVSX?

Back 14

MOVZX is for unsigned sources, and MOVSX is for signed sources

Front 15

When you copy a smaller value into a larger destination, the MOVSX instruction fills the upper half of the destination with _____ .

Back 15

1s if the value is negative or 0s is the value is positive. *NOTE* if value of register is in hex format, Fs are used instead of 1s!

Front 16

T or F:
An unsigned value can be the source when using a MOVSX instruction.

Back 16

FALSE
the source must be signed, and the destination must be a register"

Front 17

When would you use MOVSX instead of MOV?

Back 17

When the source and destination are unequal in size

Front 18

T or F:
The MOVSX instruction permits the source and destination to be different sizes.

Back 18

TRUE
the destination must be equal to or larger than the source

Front 19

What does the XCHG instruction do?

Back 19

exchanges the values of two operands

Front 20

What are the operand restrictions of XCHG?

Back 20

at least one operand must be a registry, no immediate operands are permitted, and operands must be the same size

Front 21

What is the notation for an 8-bit registry operand?

Back 21

reg8

Front 22

What is the notation for an immediate value operand?

Back 22

imm

Front 23

What is the notation for a memory operand?

Back 23

mem

Front 24

What is added to the data label to produce and effective address?

Back 24

constant offset

Front 25

How is the location of the third value in a WORD array referenced?

Back 25

[array+4] (offset + 2 + 2)

Front 26

How is the location of the second value in a DWORD array referenced?

Back 26

[array+4] (offset + 4)

Front 27

The _____ instruction increases the destination operand by one.

Back 27

INC

Front 28

The _____ instruction decreases the destination operand by one.

Back 28

DEC

Front 29

When using ADD or SUB, how many memory operands are allowed?

Back 29

one -- ADD and SUB follow the same operand rules as MOV

Front 30

What does the NEG instruction do?

Back 30

reverses the sign of the operand

Front 31

When using NEG, if the operand is nonzero, will the carry flag be set?

Back 31

yes

Front 32

Does the MOV instruction affect flags?

Back 32

no

Front 33

Following an arithmetic operation, when is the zero flag set?

Back 33

when the destination equals zero

Front 34

Following an arithmetic operation, when is the sign flag set?

Back 34

when the destination is negative

Front 35

Following an arithmetic operation, when is the carry flag set?

Back 35

when an unsigned value is out of range

Front 36

Following an arithmetic operation, when is the overflow flag set?

Back 36

when a signed value is out of range

Front 37

Can the CPU distinguish between signed and unsigned integers?

Back 37

no

Front 38

The _______ flag is set when two positive operands are added and their sum is negative.

Back 38

overflow

Front 39

The _______ flag is set when two negative operands are added and their sum is positive.

Back 39

overflow

Front 40

What does the OFFSET return?

Back 40

the distance, in bytes, of a label from the beginning of its enclosing segment

Front 41

What does the PTR operator do?

Back 41

overrides the default type of a label (variable), allowing access to part of the variable

Front 42

What does the TYPE operator return?

Back 42

the size, in bytes, of a single element of a data declaration

Front 43

What does the JMP instruction do?

Back 43

unconditionally jumps to a label

Front 44

What does a LOOP instruction do?

Back 44

creates a counting loop

Front 45

What happens if ECX has a value less than zero while within a loop?

Back 45

creates an endless loop -- the loop exits when ecx is equal to zero

Front 46

If you have a nested loop, how do you protect the count of the outer loop?

Back 46

store ecx in a variable or push it on the stack to retrieve after executing the inner loop