Comp Sci 260 Midterm

This directive identifies the part of a program containing instructions

.CODE

The byte binary representation of decimal 10

00001010

This is the content of AL after the following instructions execute :::: mov al,11001111b***** and al,00101011b

00001011

This much memory can be addressed in Real-address mode

1 MB

This is the hexadecimal value of AX when this code executes mov esi, OFFSET word1 add esi,4 mov ax,[esi]

2

This flag is set when an unsigned value is too large to fit into a destination operand

Carry

This directive enables block-style comments

Comment

This internal bus uses binary signals to synchronize actions of all devices attached to the system

Control bus

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

False

T/F The DS register can be the destination operand of a MOV instruction

False

T/F The SAHF instruction copies the EFLAGS register into a 32-bit memory location

False

This code causes a 500 millisecond delay, using a library procedure

mov eax, 500 ***** call Delay

T/F This code sequence assigns the value 10h to EBX mov edx, 20h push edx mov ecx,10h push ecx pop ebx pop edx

true

After the loop executes these are the values at locations varY, varY+4, and varY+8

0,0,1

If line 9 were changed to mov [esi-4], eax this would be the final values at location varY, varY+4, and varY+8

0,1,2

For lines 2,3,5 and 6, indicate the values of the following Flags: ZF, CF, SF, OF 1. mov al,7Fh 2. add al,2 3. sub al,5 4. mov al,80h 5. add al, 80h 6. neg al

0011 0001 1101 1000

This linear addresses matches the segment-offset address 08F0:0200

09100h

The two registers containing: 1. an integer before calling WriteDec and 2. the starting address of data when calling DumpMem

1. EAX, 2. ESI

This is the content of AL after the following instructions execute :::: mov al,00111100b**** or al,82h

10111110

The hexadecimal representation of 16d

10h

The 8-bit two's complement of binary 00000010

11111110

The values of the following are (TYPE word1) (TYPE dword1) (LENGTHOF word1) (SIZEOF word1)

2,4,3,6

This is the valye of EAX when the following sequence of instructions has executed::::: push 5***** push 10***** push 20***** pop eax

20

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

2004h

This much memory can be addressed in Protected mode

4 GB

This is the value of EAX when the following sequence of instructions has executed push 5 push 10 pop ebx pop eax

5

After the loop executes, these will be the values in the last three positions (array elements) of varY

6,7,8

Indicate the hexadecimal value of the destination operand next to each instruction. Use the letter I to indicate that a particular instruction is invalid mov ax,[word3+2] eax,[dword1+4] mov al,[byte1+1] mov eax,[word3+4]

8000h 00000020h 1 invalid

This is the final hexadecimal value of AX when this code executes mov ebx,OFFSET dword1 sub ebx,2 mov ax,[ebx]

9000h

The basic parts of an instruction, in order from left to right, are: a. label, mnemonic, operand(s), comment b. comment, label, mnemonic, operand(s) c. label, mnemonic, comment d. mnemonic, operand(s), comment

A. label, mnemonic, operand(s), comment

This is where within the CPU, all calculations and logic operations take place inside

ALU (Arithmetic Logic Unit)

The expression NOT X AND X

Always false

The expression NOT X OR X

Always true

Given the following array definition, what is a valid constant declaration named ArrayCount that automatically calculates the number of elements in the array? newArray DWORD 10,20,30,40,50

ArrayCount = ($ - newArray)/4

This utility program reads an assembly language source file and produces an object file

Assembler

Which of the following are true about assembly language instructions and directives? a. a directive is executed at runtime b. an instruction is executed at runtime c. a directive is executed at assembly time d. an instruction is executed at assembly time

B and C

This byte=ordering scheme used by computers to store large integers in memory with the high-order byte at the lowest address is called

Big Endian

Which of the following will generate assembly errors? a. var1 BYTE 1101b, 22, 35 b. var2 BYTW "ABCDE",18 c. var3 BYTE '$','98778', d. var4 BYTE 256,19,40

C and D

The two types of real-number constants are: a. decimal, binary b. encoded, binary c. decimal, encoded d. BCD, ASCII

C. decimal, encoded

This high-speed memory reduces the frequency of access by the CPU to conventional memory

Cache memory

This is the value of ECX when the following sequence of instructions has executed::::: push 5**** push 10**** pop ebx**** pop eax**** pop ecx

Cannot be determined

These are the three types of buses connected to the CPU

DATA, ADDRESS, and CONTROL

This directive can be used in place of the BYTE directive for unsigned integers

DB

The name of the lowest 8 bits of the EDX register

DL

Indicate the hexadecimal value of the destination operand next to each instruction. Use the letter I to indicate that a particular instruction is illegal mov dx, word3 movsx eax, byte1 mov dh,al mov bx,dx

DX = 7FFFh EAX = FFFFFFFFh DH = FFh BX = FFFFh

These are two types of labels in assembly language programs

Data Labels and Code Labels

This register is known as a loop counter

ECX

This directive prevents a constant to be redefined in a program

EQU

This two 32-bit registers are known as extended index registers

ESI and EDI

word1 WORD 1000h,2000h,3000h,4000h,5000h dword1 DWORD 10000h,20000h,30000h,40000h This is the final value of AX after this code has executed mov esi, OFFSet word1 mov ecx,5 mov eax,100h L1: add ax,[esi] add ax,16 add esi,TYPE word1 Loop L1

F150h

If you were to multiply 1.5 by 2.6, you use this part of the CPU

FPU (floating point unit)

T/F The MOV instruction permits a move between two memory operands, as long as one operand uses the DWORD PTR operator

False

T/F The compiler decodes and executes one program statement at a time

False

T/F The following instruction will produce 1FFFFFFCh in EAX: movsx eax,-4

False

T/F The following instruction will set the CArry flag: mov al,0FEh sub al,2

False

T/F The following is a valid identifier: AB62-$

False

T/F The sum of all powers of 2 between 20 and 28 is 255

False

This procedure locates the cursor at a specific row and column on the screen

Gotoxy

A map file is produced by this utility programs

Linker

This program combines object files into an executable program.

Linker

This file contains a list of program symbols

Listing File

This defines a text macro named MESSAGE that contains "I'm good at this!",0

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

This instruction pops the stack into the FLAGS register

POPFD

This instruction pushes the 32 bit FLAGS registers on the stack

PUSHFD

If you wanted to find out whether an integer contained an even number of 1 bits, you set this status flag

Parity

Segment-offset addressing is used in this processor mode(s)

REAL ADDRESS MODE and VIRTUAL-8086

This directive is used when defining 64-bit IEEE long reals

REAL8

Write a procedure named Read10 that reads exactly ten characters from standard input into an array of BYTE named myString. Use the Loop instruction with indirect addressing, and call the ReadChar procedure from the book's link library. (ReadChar returns its value in AL.)

Read10 PROC**** MOV ECX, LENGHTOF myString**** MOV ESI, OFFSET myString**** L1: call ReadChar**** MOV [esi], AL**** INC ESI**** Loop L1**** RET Read10 ENDP

This is a word that has special meaning to the assembler and can only be used in its correct context.

Reserved Word

This component of an operating system is responsible for switching control between tasks

Scheduler

Write a procedure named ShowBinary that displays the following array as a sequence of binary bits, starting with the low-order value (00000010h). Include the use of the LEGNTHOF, OFFSET, and TYPE operators, and call the WriteBin procedure array DWORD 10h, 20h, 30h, 40h

ShowBinary PROC MOV ECX, LENGTHOF array MOV ESI, offset array L1: move eax, [esi] call WriteBin add esi,TYPE array Loop L! RET ShowBinary ENDP

This directive is used when defining 80-bit integers

TBYTE

T/F A virtual machine may be constructed from software

True

T/F Adding 5 to 0FBh in an 8-bit register sets the Zero flag

True

T/F Adding 7Fh and 05h in an 8-bit register sets the OVerflow flag.

True

T/F Operands can be constant or constant expression, register name, and variable name (memory)

True

T/F Suppose there is a virtual machine containing levels V1 and V2, where V2 is above V1 in the machine hierarchy. The programs written in language V2 can be executed by a program running at level V1

True

T/F The INC instruction does not affect the Carry flag

True

T/F The MOV instruction does not permit an immediate value to be moved to a segment register

True

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

True

T/F The following are both valid data definition statements: List1 BYTE 10,20 BYTE 30,40

True

T/F The following instructions will set the Sign flag: mov al,0FEh sub al,2

True

T/F The following is a valid data definition statement: prompt BYTE 'CSU EAST BAY', 0

True

T/F The following statement will assemble without errors mov WORD PTR [edx],1234h

True

This library procedure writes an unsigned 32-bit integer to standard output in hexadecimal format

WriteHex

For each of the following instructions, indicate whether it is valid (V) or invalid (I) a. move byte2,0FFh b move word1,byte2 c. mov word2,10000h mov si,word1

a. V b. I c. I d. V

This code writes a sequence of statements that read a signed integer from standard input and write the same integer to standard output. Us library procedures

call ReadInt call WriteInt

This instruction ( a function call ) writes the contents of EAX to standard output as a signed decimal integer?

call writeInt

T/F A WHILE loop can be constructed with a CMP instruction at the bottom of the loop, followed by a conditional jump instruction.

false

T/F The PUSH instruction increments the stack pointer (by 2 or 4) and copies the operand into the stack at the location pointed to by the stack pointer.

false

T/F The assembler knows the exact address of a library procedure

false

This file acts as a bridge between Irvine32.lib and kernel32.dll

kernel32.lib

This code uses library procedure to generate a single unsigned pseudorandom integer between 0 and 999 and write it to standard output

mov EAX, 1000 call RandomRange call WriteDec

Without modifying dword1, ECX, and EDX this is the implementation of the expression eax = -dword1 + (edx - ecx) + 1

mov eax,dword1 neg eax move ebx,edx sub ebx,ecx add eax,ebx inx eax

This code will display the following string to standard output str1 BYTE "Display this string",0

mov edx, offset str1 call WriteString

This code displays the following array in hexadecimal, using the DumpMem procedure from the link library:::::array DWORD 10h,20h,30h,40h

mov esi, offset array move ecx, lengtof array mov ebx, type array call dumpMem

This statement moves a video color constant to EAX. The constant should represent black text on a white background, (using the constants in the Irvine32.inc file)

move eax, black + (white*16)

This definition creates an array of unsigned bytes containing decimal 10,20, and 30, named myArray

myArray BYTE 10,20,30

This statement creates an array of 500 signed doublewords named myList and initializes each array element to the value -1.

myList SDWORD 500 DUP (-1)

This code a Proc declaration for a procedure named MySub. It uses the USES operator to preserve the EAX and EBX registers

mySub PROC USES EAX EBX