CS 271 Midterm

Which library procedure locates the cursor at a specific row and column on the screen?

Gotoxy

(T/F) When an argument is passed by value, a copy of the address is pushed on the stack.

False

A stack is also called a FIFO structure (First-In, First-Out) because the last value put into the stack is always the first valuetaken out.

False

Adding 0FFh and 05h in an 8-bit register sets the Overflow flag.

False

Code labels may only appear on lines with no instructions.

False

Given an odd-parity system which checks parity 16 bits at a time, the following data would be flagged as having an error. 1101 1011 0010 1010

False

If the LOOP instruction sets ECX to zero, a jump to the destination label does take place.

False

MASM is case-sensitive

False

System endianness will impact the ordering (indexing) of elements in an array.

False

The Stack Segment register always points to the top of the runtime stack.

False

An Assembly Language is defined by the

Instruction Set Architecture (ISA)

Which library procedure sets the Zero flag if the AL register contains the ASCII code for a decimal digit (0-9)?

IsDigit

JA

Jump if leftOP > rightOP (unsigned)

JE

Jump if zero

What does the END directive do? (Check all that apply)

Marks the end of the module, Sets the entry point (procedure) for the program

Arrays are passed by reference to avoid copying each element into the stack/registers.

True

By default, code labels are visible only within the procedure in which they are assigned (created).

True

Given an odd-parity system which checks parity 16 bits at a time, the following data would be flagged as having an error. 1111 1001 1011 1000

True

In a Von Neumann architecture, each instruction in a program may be individually addressed and accessed.

True

One cause of bit errors is signal noise.

True

When values are received by a called subroutine, they are called

parameters

In debugging mode, which of the following (when typed into the memory window's address bar) will directly jump to the first memory address of variable userName?

&userName

10110010 + 10100001

101,010,011

Complete the following Unsigned Binary Addition (answers should also be in Binary): 10110010 + 10100001

10101 0011

The stack frame inside a procedure is also known as the

Activation Record

Convert the following ASCII hex representation to a character string: 41 77 65 73 6F 6D 65

Awesome

Which of the following instructions always modify the ESP register? (Check all that apply)

CALL, RET, POP, PUSH

Which answer choice shows the correct values of the Carry, Zero, and Sign flags after the following instructions execute? mov al,00110011btest al,2

CF = 0, ZF = 0, SF = 0

Adding 5 to 0FBh in an 8-bit register sets the Zero flag.

True

Values passed to a subroutine by a calling program are called

arguments

The byte-ordering scheme which stores integers in memory with the most significant byte at the lowest address (first) is called:

big endian

System endianness affects:

byte-wise ordering

Which of the following CALL instructions writes the contents of EAX to standard output as a signed decimal integer?

call WriteInt

A loop which executes at least one time, and possibly more, is called a

post-test loop

the parity flag

set if the least-significant byte in the result contains an even number of 1 bits

the carry flag

set when an unsigned arithmetic operation generates a carry (or borrow) out of the most significant bit of the result

JG

Jump if leftOp > rightOp (signed)

(T/F) The linker combines object files into an executable file.

True

The MOVSX instruction sign-extends an integer into a larger operand.

True

Place the steps for a memory read in the correct order.

(1) Specify the memory address on the Address Bus via MAR. (2) Assert a Read (3) Wait until operation is complete (4) Move data to its destination

Convert the following signed SWORD to a decimal value. 1100 1101 0011 1100

-12,996

What is the range of decimal values for a signed BYTE?

-128 to 127

Convert the following signed SWORD to a decimal value. 1111 0000 0001 1001

-4,071

Which directive identifies the part of a program containing instructions? Use correct syntax.

.code

Write the syntax to set the size of the runtime stack to 2048 bytes.

.stack 2048

Which of the following binary values is equivalent to hexadecimal 7CBE?

0111 1100 1011 1110

11010010 - 01011100

01110110

Convert the following value from signed decimal to 8-bit binary: -33

1101 1111

What is the largest unsigned integer that may be stored in 24 bits?

16,777,215

What is the minimum size of a data type, in bytes, to be impacted by system endianness. (Whole numbers only)

2

The four-byte hexadecimal sequence 52 A5 8A 80 stored in consecutive memory cells in a little-endian architecture represents ___________ (decimal) when interpreted as a 32-bit unsigned integer.

2,156,569,938

In the following data definition, assume that List2 begins at offset 2000h. What is the offset of the third value (5)? List2 WORD 3,4,5,6,7

2004h

Which list contains the correct hexadecimal translation (in order) of the following unsigned decimal integers? 33, 95, 257

21, 5F, 101

What is the largest signed integer that may be stored in 32 bits?

2^31 - 1

How many bits long is a DWORD (doubleword) on x86 systems?

32

5568 - 1ADC

3A8C

How many bytes long is a DWORD (doubleword) on x86 systems?

4

The RET instruction (without operands) will pop how many bytes off the stack?

4

Convert the following unsigned WORD to a decimal value. 1011 0100 0101 0101

46,165

Convert the following string into its ASCII hex representation: MagicalDon't use 0x or h to represent the hex values.

4D 61 67 69 63 61 6C

The four-byte hexadecimal sequence 65 25 83 03 stored in consecutive memory cells in a little-endian architecture represents ___________ (decimal) when interpreted as a 32-bit signed integer.

58,926,437

Convert the following unsigned WORD to a decimal value. 1111 1010 0000 1111

64,015

Which list contains the correct hexadecimal translation (in order) of the following unsigned decimal integers? 33, 95, 257

6A, 5F, 101

How many bytes long is a QUADWORD on x86 systems?

8

How many bytes long is a SQWORD on x86 systems?

8

Complete the following Unsigned Hexadecimal Addition (answers should also be in Hexadecimal): 2C09 + 571B

8,324

Complete the following Unsigned Hexadecimal Addition (answers should also be in Hexadecimal): 2C17 + 572B

8,342

If you are using an integer constant in one of your CS271 programs, which constant method must you use?

=

An SDWORD storing the integer value -540,000 (FFF7C2A0h) is stored in memory on a little-endian system starting at memory address α. What Hex value is stored at each of the following memory addresses? (A, A+1, A+2, A+3)

A0, C2, F7, FF

What unit on a CPU chip is responsible for computing basic addition and subtraction operations?

ALU

Another name for a stack frame is

Activation record

Convert the following ASCII hex representation to a character string: 41 72 63 68 69 74 65 63 74

Architect

What mechanism is used to turn Assembly Language code to Machine Code?

Assembler

A --- Architecture's instructions are decoded to micro-programs which are executed by the CPU, whereas a --- Architecture's instructions are directly executed by the CPU.

CISC, RISC

Which flag is set when the result of an unsigned arithmetic operation is too large to fit into the destination?

Carry

Language Hierarchy: The purpose of a Compiler is to...

Convert High/Low level Program Code to Assembly/Machine Code

The ________ procedure advances the cursor to the beginning of the next line in the console window.

Crlf

When transferring instructions and data between the Main Memory Unit and the CPU, they will be placed on the Address Bus.

Data

Which library procedure displays the CPU flags and 32-bit registers?

DumpRegs

The ___ register holds the 32-bit address of the next instruction to be fed to the instruction execution cycle.

EIP

When branching, which register's value changes? (Enter the three-letter register abbreviation only)

EIP, IP

Language Hierarchy: Rank the following languages from low level (1) to high level (4).

English, Python, ARM Assembly, Machine Code

In debugging mode, which function key is will execute a library procedure, then stop on the next instruction after the procedure?

F10

In debugging mode, what is the keyboard shortcut to continue execution to the next breakpoint (or to the end of the program if no more breakpoints exist)?

F5

(T/F) Code labels may only appear on lines with no instructions.

False

(True/False) In debugging mode, the values of watched variables/registers may only be viewed in hexadecimal format.

False

High-level languages always pass arrays to subroutines by value.

False

If they did not have error detection/correction, WiFi systems would almost never send/receive signals containing bit errors.

False

The number 117.2 can be represented exactly in IA-32 Floating Point Unit 32-bit IEEE 754 format.

False

x86-64 systems default to big-endian byte ordering.

False

Which of the following is true about the PUSH instruction?

It decrements the stack pointer (by 2 or 4), and then copies the operand into the stack at the location pointed to by the stack pointer.

JECXZ

Jump if the counter register is zero

Which of the following statements correct makes a constant integer defining a maximum integer value of 365?

MAXVAL = 365

Which of the following defines a text macro named MESSAGE that contains this string data? "I'm good at this!",0

MESSAGE TEXTEQU <"I'm good at this!",0>

What instruction (with any necessary operands) would pop the top 32 bits of the runtime stack into the EBP register?

POP EBP

What single instruction would I use to save all general purpose registers?

PUSHAD

What instruction would I use to save the current value of the flags register?

PUSHF

If you wanted to find out whether an 8-bit integer contained an even number of 1 bits, which status flag would be useful?

Parity

What would you call an ordered list of organized instructions existing somewhere in memory, and associated with a data structure for storage of data?

Program

The CALL instruction functions similarly to which of the following?

Push, then Jump

Which library procedure generates a 32-bit pseudorandom integer in a caller-specified range?

RandomRange

Which library procedure reads a 32-bit signed decimal integer from standard input?

ReadInt

Which of the following are normally part of the stack frame? (Select all that apply)

Saved Register Values, Arguments, Local Variables, Return Address

the overflow flag

Set when the result of a signed arithmetic operation is too large or too small to fit into the destination

Identify the sizes (in bits) of the sign, biased exponent, and normalized mantissa for a Single Precision x86 floating point value.

Sign: 1 bits, Biased Exponent: 8 bits, Normalized Mantissa: 23 bits

What advantages do stack parameters have over register parameters?

Stack parameters reduce code clutter because registers do not have to be saved and restored. Stack parameters are compatible with high-level languages.

A stack frame is

The area of the stack set aside for passed arguments, return address, local variables, and saved registers.

Match the Instruction Execution steps to the correct order and description.

The control unit (1) fetches the next instruction from queue, (2) increments instruction pointer (IP), (3) decodes the instructions function. (4) the instruction uses an input operand from memory, (5). ALU executes the instruction, (6) if output operand is in memory, the control unit uses write operation to store data

(T/F) In MASM all text following a semicolon (on the same line) is treated as a comment and ignored when the program is converted to machine code.

True

(T/F) The MOVSX instruction sign-extends an integer into a larger operand.

True

(True/False) Higher level languages are more likely to be portable than lower level languages.

True

A primary limitation on the speed of internal communication on a machine is the width of the internal bus.

True

A subprocedure's stack frame contains the return address and its local variables.

True

Adding 7Fh and 05h in an 8-bit register sets the Overflow flag.

True

An IEEE 754 Floating Point value contains three components: a sign, a normalized mantissa, and an biased exponent

True

An argument passed by reference consists of a memory address offset

True

An argument passed by reference consists of a memory address offset.

True

An input parameter may be passed by reference.

True

In the IA32 architecture, ESP (the stack pointer) is incremented each time data is popped from the stack.

True

In the IA32 architecture, ESP (the stack pointer) is incremented each time data is pushed onto the stack.

True

In the IA32 architecture, the top item on the stack will always have a lower memory address than the bottom item.

True

Passing by reference requires accessing a parameter's offset from inside the called procedure.

True

The following are both valid data definitions: List1 BYTE 10, 20 BYTE 30, 40

True

What general types of parameters are passed on the stack

Value parameters, Reference parameters

In debugging mode, a ----- is a point in the program where execution will be paused.

breakpoint

In debugging mode, a ___ is a point in the program where execution will be paused.

breakpoint

_____ branching means that we either branch or don't branch depending on the outcome of a logical condition. _____ branching means jumping to another location in the program without checking any conditions.

conditional branching / unconditional

Operands may be any of the following:

constant or constant expression, register name, variable name (memory)

The three types of buses connected to the CPU are

data, address, control

An even parity system requires an ________ number of '1'-bits for parity.

even

JC

jump if carry

JNZ

jump if not zero

The basic parts of an instruction, in order from left to right, are

label, mnemonic, operand(s), comment

A program that combines object files into an executable program is called a

linker

A signed integer stores the sign in

most significant bit (MSB)

Which of the following BYTE declarations are allowed in MASM? (Check all that apply) myByte2 BYTE 'Fancy' myByte1 BYTE "Hot ", 'Dog', 33, 0 myByte4 BYTE "nested 'quotes' " myByte5 BYTE 'W','o','r','s','t','!',0 myByte3 BYTE 'simple 'quotes' '

myByte2 BYTE 'Fancy' myByte1 BYTE "Hot ", 'Dog', 33, 0 myByte4 BYTE "nested 'quotes' "

A/An ________ procedure call occurs when a called procedure calls another procedure before the first procedure returns.

nested

the sign flag

set when the result of an arithmetic or logical operation generates a negative result

the zero flag

set when the result of an arithmetic or logical operation generates a result of zero.

Conditional jumps check flags in which register before jumping?

status register