cs401 collection of old papers

Write valid instruction(s) to perform each function specified below.

Question No. 2 Marks : 10

e. What are minimum numbers of pins required for serial communication? Also write their names?

d. What is multitasking? c. Why cli and sti instructions are used during hooking an interrupt?

b. Why procedures are used and what must be the last executable instruction in a procedure?

a. What is the change in the stack after int instructions is executed? Answer the following Questions briefly.


Total Marks: 60 Total Questions: 4

All Coding questions should be answered using the Assembly language syntax.

6. Your paper contains 4 questions. 5. You have been provided with all assembly tools so you can use assembly tools also.

b. If you believe that some essential piece of information is missing, make an appropriate assumption and use it to solve the problem.

a. If you think that there is something wrong with any of the questions, attempt it to the best of your understanding.

4. Do not ask any questions about the contents of this examination from anyone.

b. You will have to answer correctly all questions in this examination to get the maximum possible marks.

a. There is no choice. 3. Answer all questions. 2. This examination is open Handouts. 1. The duration of this examination is 120 minutes.

Please read the following instructions carefully before attempting any question: Instructions

Time Allowed: 150 Minutes

Final Term Examination - February 2005

CS401 Computer Architecture and Assembly Language Programming

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ii.[ebx+esi-0x0012FD] i. [bx+si]

b. Write 32 bit physical addresses for the following accesses where Base = 0x00A00000 and Limit = 0x30000, EBX contains 0x00001000, and ESI contains 0x00003000

ii. 32-bit Read only data segment at level 0, with base at 0x00A0BBBB and limit of 0x1CCCC.

i. 32 bit, non conforming, execute-only code segment at level 2, with base at 0x00403333 and a limit of 0x0FFFF.

5 r bit = 0 4 AVL bit = 1 3 G bit = 0 2 P bit = 1 1 A bit = 0

Assume following values for attributes

dd 0x0000FFFF, 0x00CF9A00

a. Write the following descriptors in the format Answer the following regarding Protected Mode descriptors

Question No. 4 Marks : 10 (Well commented and well indented program will be given extra mark)

Write a function "ConvertBinaryToDecimal" that takes the address of a string containing binary of any decimal number via the stack. The function should print its equivalent decimal number. For example, if the string is "11011" then after the execution of this function, the program should print 27 and if the string is "1001" then after the execution of this function, the program should print 9 on the screen.


e. Provide instruction(s) to write value of al at the port 0x12. d. Provide instruction(s) to divide value of ax by 8. c. Provide instruction(s) to move value of flag register in ax. b. Provide instruction(s) to move the value at the top of stack in ip register. a. Provide instruction(s) to read a value from port number 0x312.

Write the values of limit A bit , P bit and AVL bit of the following descriptors. Answer the following regarding protected mode descriptors:



Best of Luck


6. Your paper contains 4 questions.

5. You have been provided with all assembly tools so you can use assembly tools also.








Final Term Examination – Spring 2005



add ax, bx mov bx, [num2] mov ax, [num1] [org 0x0100]

;;---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

What will be the values in num1 and num2 after the execution of the code given below?

II. Consider the following code:

;;--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Find: dw 0 num1: dw 15 int 0x21 mov ax, 0x4c00 mov [Find], ax jnz l1 sub cx, 1 l1: add ax, cx mov ax, 0 mov cx, [num1] [org 0x0100]

;;-----------------------------------------------------------------------------------------------------------------------------------

What would be in the variable Find after the execution of the code given below?

I. Consider the following code: Question No. 3 Marks : 10

2. Why we need to disable interrupts before we attempt to change the stack (i.e. ss and sp).

1. Why we need to disable the interrupts while calling interrupt INT 80hj. Give the short answer of the following:


2. dd 0x F8E2135A , 0 x 13DC1258 1. dd 0x 00FEADEF , 0x 00B60718

15 7 19 13 No 5 7 9 13 Yes If array is: Output Some sample output is shown below,

Write a function "ShowResult" that takes the address of two memory locations via the stack, the one pushed first is the address of an array of integers and the second is the length of that array. The function should print "Yes" if the array is in ascending order and "No" if it is not.


;;-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

num2: dw 10 num1: dw 5 int 0x21 mov ax, 0x4c00 add ax, bx sub bx, ax

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mov ax, 0xb800 clrscr: mov word[cs:count jmp exit cmp word[cs:count] inc word[cs:count] push es p push cx timer: push di second: dw 0 acount: dw 0 jmp start [o

Explain the purpose and working of the following pro


4. Any one can set

2. Organization 1. Processor err pt Flag is set

Question No. 1

Final Term Examination – Spring 2006 Time Allowed: 150 Minutes

Marks : 1 Int u by

3. Programmer

gram. Also, write comments in front of each instruction describing the purpose of that particular instruction.

rg 0x0100]

ttribute: dw 0x07

ush ax

, 91

je clrscr

], 0

CS401

c. ROL AL, CL if CL contains 2 b. SHR AL, 1 a. SHL AL,1

e the precedfoSuppose AL contains 11001011b and CF= 1. Give the new contents of


shr dx, cl mov cl, 4 add dx, 15 mov dx, st sti mov word [es:8* cli mov es, ax start: xor ax, ax pop cx pop ax pop es out 0x2e rep stosw mov cx, 2000 next: mov ah, [cs:attribu mov word[cs:attribute], 0x0 jbe next add word[cs:attribu mov al, 0x20 xor di, di

te], 0x10 cmp word[cs:attribute], 0x77

7

te]

cld

xit: mov al, 0x20 0, al

pop di iret

4], timer mov [es:8*4+2], cs

art

mov ax, 0x3100 int 0x21

AL after each of the llowing instructions is executed.

Assum ing initial conditions for each part of this question

mov es, ax

wer the following questions:

Question No. 8

3. 16 bits4. None o

2. 24 bits 1. 32 bits

e of sele

Question No. 7

4. None of the given options

3

e2. One's-complement number1. Two's-complement numb

IM

on No

Q

ue of bp will be zero 4. Val

3. Value of bp will be less the

1. bp will retain its original value

pop bp sub sp, 2

Read the following push bp mov bp, sp

Question No. 5

lag 3. interrupt F4. Directi

2. Trap Flag 1. Sign Flag

Question No. 4

L,CL if CL contains 3 e. RCR A

d. SAR AL, CL if CL contains 2

Marks : 1

Which flag has a special role in debugging?

on Flag

Marks : 1

code and tell what will be the final effect on bp value

mov bp, sp

2. Value of sp will move to bp n sp

uesti . 6 Marks : 1

UL and IDIV operate on

rs s

. All of the given options

Marks : 1

The siz ctor register in protected mode is

f the given options

Marks : 1

Ans

A

ii. 32 bit writeable data segment at level 2, with base at 0x00B00000 and limit of

i. 32 bit nonconforming, readable code segment at level 0, with base at 0x003000limit of 0x

he following descriptors in the format: dd 0x0000FFFF, 0x00CD9A40

Question No. 9

d. When an interrupt handler finishes, how does the CPU resum

b. What is difference between the fault and trap exception? When a key is pressed on the keyboard, which

practical uses? nd? What are some of its

c. hardware interrupt is executed? e execution to whatever it

was doing before the interrupt was triggered? e. At which address is the interrupt vector for INT 10h stored?

Marks : 1

Write t00 and a

0FFFF.

0x10000. ssume the values for the attributes bits are A=1, AVL=0, P=1, r=0, G=0, D=1, E=0 and B=1.

a. Which processor interrupts the system 18.2 times per seco

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FINALTERM EXAMINATION

SPRING 2007

CS401 - COMPUTER ARCHITECTURE AND ASSEMBLY LANGUAGE PROGRAMMING (Session - 5

)

Marks: 65

Time: 150min

StudentID/LoginID: ______________________________

Student Name: ______________________________

Center Name/Code: ______________________________

Exam Date: Wednesday, July 18, 2007

Please read the following instructions carefully before attempting any of the questions:

1. Paper contains 15 questions in all, 10 MCQs and 5 subjective, attempt all questions. Marks are written adjacent to each question.

2. Do not ask any question about the contents of this paper from any one.

a. If you think that there is something wrong with any of the questions, attempt it

to the best of your understanding.

b. If you believe that some essential piece of information is missing, make an

appropriate assumption and use it to solve the problem.

c. Write all steps/instruction for a program, missing steps/instructions may lead to deduction of marks.

3. Exam is Closed Book. No handouts or reference material is allowed in exam hall other than rough sheet which will be provided by the examiner.

4. All the coding language should be based on NASM assembler.

5. No assembly software is allowed in the exam center.

6. Use of cell phone during the examination is strictly prohibited, otherwise strict disciplinary action will be taken as per university rules.

For Teacher's use only Question 1 2 3 4 5 6 7 8 9 10 Total

Marks Question 11 12 13 14 15

Marks Question

Marks

Question No: 1 ( Marks: 1 ) - Please choose one Sun SPARC Processor has a fixed ______________ instruction size. ►

16bit

►

32bit

►

64bit

►

20bit

Question No: 2 ( Marks: 1 ) - Please choose one When the subprogram finishes, the ____________________ retrieves the return address from the stack and transfers control to that location. ►

RET instruction

►

CALL instruction

►

POP instruction

►

Jump instruction

Question No: 3 ( Marks: 1 ) - Please choose one A 32 bit address register can access upto __________ of memory. ►

1 GB

►

6 GB

►

4 GB

►

2 GB

Question No: 4 ( Marks: 1 ) - Please choose one The value of a segment register when the processor is running under protected mode is called ___________________________ ►

segment descriptor

►

segment selector

►

global descriptor table

►

protected register

Question No: 5 ( Marks: 1 ) - Please choose one FS and GS are two ___________________ in protected mode. ►

segment registers

►

segment selectors

►

stack pointers

►

register pointers

Question No: 6 ( Marks: 1 ) - Please choose one IRQ 0 interrupt have _______________ priority ►

low

►

medium

►

highest

►

lowest

Question No: 7 ( Marks: 1 ) - Please choose one IDT stands for ______________________. ►

interrupt descriptor table

►

individual descriptor table

►

inline data table

►

interrupt descriptor table

Question No: 8 ( Marks: 1 ) - Please choose one Every bit of line status in serial port conveys _____________ information. ►

different

►

same

►

partial

► full

Question No: 9 ( Marks: 1 ) - Please choose one There are total _______________ bytes in a standard floppy disk. ►

1444k

►

1440k

►

1280k

►

2480k

Question No: 10 ( Marks: 1 ) - Please choose one An 8x16 font is stored in _________________ bytes. ►

8

►

16

►

4

►

20

Question No: 11 ( Marks: 10 ) Give answers to these questions. . [ 3+4+3]

1. Differentiate hardware and software interrupts? 2. Give an example of the priority mechanism in the programmable interrupt controller? 3. Why memory must be freed using explicit calls to DOS before executing a program?

Question No: 12 ( Marks: 15 ) Part a) Calculate the physical memory address generated by the following segment offset pairs. [2 x 2.5]

a. 1DDDh:0436h b. 1234h:7920h

Part b) Fill out the corresponding values in HEX in the register table after the execution of each instruction. Every instruction is dependent on the previous instruction and carry flag is reset in the start. [2 x 5] Instructions

Al Carry Flag

mov al,0x005D Shr al,0x0003 Mov al,0x003C

Sar al,0x0006 mov ax,0x12D4

Question No: 13 ( Marks: 10 ) Which BIOS interrupt provides serial port services and list down names of 9 pins of DB-9 connector. [10]

Question No: 14 ( Marks: 10 ) Write a program to print your full name followed by your student ID using bios services. [10]

Question No: 15 ( Marks: 10 ) Describe the following descriptors. Give its type and the value of all their fields:

dd 01234567h, 789ABCDEh


Note: String is assumed to contain only small case legal letters and length of the string is fixed to 15 characters. Vowel characters include a, e, i, o, u.

Write a program named "Countvowels" that counts all occurrences of the vowels in a source string and then prints the result in the format (vowel, count). For example if the string is 'afadefsoieaid' it should print (a,3) (e,2) (i,2) (o,1) (u,0) on the screen. The program should take address of the source string as a parameter via stack. Also provide proper comments against each instruction.




6. Your paper contains 4 questions. 5. You have been provided with all assembly tools so you can use assembly tools also.








Mid Term Examination - November 2004



mov cx, dx mov [ numarray + bx ], cx mov bx, [ index2 ] mov [ bp + bx ], dx mov bx, [ index1 ] mov [ index2 ], bx mov dx, [ numarray + bx ] swap:

jmp swap jc swap cmp cx, [ numarray + bx ] je end cmp bx, 20 add bx, 2 swap: add ax, 2 mov cx, [ numarray + bx ] mov [ index1 ], [ index2] mov bh, ax je num1 cmp ax, 20 loop: mov bx, 0 mov ax 0 start: index2 dw 0 index1 0 numarray dw 7, 11, 5, 0, 3, 1, 9, 4, 2, 10 jmp start [0x0100]

Example: push IP ; IP can't be pushed on the stack.

Find all the errors in the following code and write those errors against each erroneous instruction.


d. 0000 c. 1234 b. F009 a. FFFF

Calculate the first and the last physical memory addresses accessible using each of the following segment values?


e. What is the difference between SUB and CMP instructions? d. What does the INT 21h accomplish if AH contains 4CH? c. What is FAR jump? b. Explain what the REP prefix does? a. What does the symbol [ ] indicate?

Answer the following questions.

e. rcl ax, 2 if carry flag = 0 d. and ax, bx c. not ah b. ror bx, 2 a. xor ah, bh

If AX= 0x44FF and BX= 0x011F

What will be the value of AX after the execution of each of the following instruction? Each instruction is independent of others.


mov ax, 0x4c00 end: jmp start


iv. MOV [BYTEVAR], 20 iii. MOV [BX], [DI] ii. MOV ES, SS i. MOV BL, CX What is wrong with each of the following instructions? Question No. 1 Marks : 10


5. Your paper contains 4 questions.

4. You have been provided with all assembly tools so you can use assembly tools also.





a. There is no choice.

2. Answer all questions.

1. This examination is open books, open handouts and quiet neighbors.

Please read the following instructions carefully before attempting any

question:


Mid Term Examination – Spring 2006 CS401 Assembly Language

mailto:[email protected]




int 0x21 mov ax, 0x4d00

end: jmp label2 mov bx, [index1] mov [var3 ], cx mov [var2+bx], [var1+bx]

swap:

jmp label2 jc swap cmp [si+di], cx je here cmp bx, [bx+bp] add bx, 2

label2:

add ax, [bx-si] mov cx, [var1+ bx] mov [var2], bx mov bh, ax je end cmp ax, 20

label1: mov bx, 0 mov 5, 0

start: var3 dw 0 var2 dw 0 var1 dw 34, 21, 25, 20, 23, 21, 29, 14, 42, 10

jmp start [org 0x0100]

Find errors in the code given below and write error description against each erroneous instruction.

Question No. 2 Marks : 10 v. MOV [02], [ 92]

iv. Provide instruction to divide value of AX by 8. iii. Provide instruction to move value of flag register in AX. ii. Provide instruction to move the value at the top of the stack in IP register i. Provide instruction to read a value from port number 0x312 b) Write valid instruction(s) to perform each function specified below.

Write code to replace each lowercase letter in the following string by its upper case equivalent. Use index address mode.

MSG: db ‘this is a message’ a) Consider Question No. 4 Marks : 20

e. What is the function of segment override prefix and what changes it brings to the opcode?

d. What is the difference between little endian and big endian formats? c. What is the difference between a TEST and AND instruction? b. Write a instruction to change the sign bit of AX. a. Which registers are changed by the CMP instructions? Answer the following Questions.

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MIDTERM EXAMINATION

SPRING 2007

CS401 - COMPUTER ARCHITECTURE AND ASSEMBLY LANGUAGE PROGRAMMING (Session - 1 )

Marks: 45

Time: 90min

Q: Give the new values of AX and DX for each of the following instructions, or tell if the overflow occurs. [2.5 x 4] a. DIV BX, if DX contains 0x0000, AX contains 0x0007, and BX contains 0x0002 b. DIV BX, if DX contains 0x0000, AX contains 0xFFFF, and BX contains 0x0010 c. IDIV BX, if DX contains 0xFFFF, AX contains 0xFFFC, and BX contains 0x0003 d. DIV BX, if DX contains 0xFFFF, AX contains 0xFFFC, and BX contains 0x0003 Q: Fill in the Blanks [5] 1) In the MOV instruction both operands i.e. source and the destination cannot be _______________ operands. 2) The MOVZX instruction can be used only with _____________ integers. 3) Consider the following code segment mov bl,9B movsx cx,bl

Write down the 16-bit value for cx in the space below

cx

4) Name any two basic type of operands a. ___________ b. ___________ 5) The INC and Dec instruction do not effect the __________ flag

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Q: Consider the following pseudo-code and write the corresponding assembly code for it. [10] Note: Try to write a shorter code. If ( al>bl) AND (bl> cl) { cx = 1 } Q: Give the value of the zero flag, the carry flag, the sign flag, and the overflow flag after each of the following instructions if AX is initialized with 0x1254 and BX is initialized with 0x0FFF. [10]

a. add ax, 0xEDAB b. add ax, bx

add bx, 0xF001 Q:Write a program to swap every pair of bits in the AX register. [10] For example If AX = 1001100110011001(binary) Or AX= 0x9999 (hex) Then after the program execution it must contain this value AX = 0110011001100110 (binary) or AX= 0x6666 (hex)

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SPRING 2007

CS401 - COMPUTER ARCHITECTURE AND ASSEMBLY LANGUAGE PROGRAMMING (Session - 6

)

Marks: 45

Time: 90min

StudentID/LoginID: ______________________________

Student Name: ______________________________

Center Name/Code: ______________________________

Exam Date: Saturday, May 12, 2007

Please read the following instructions carefully before attempting any of the questions:

1. Attempt all questions. Marks are written adjacent to each question.

2. Do not ask any question about the contents of this examination from any one.

a. If you think that there is something wrong with any of the questions, attempt it

to the best of your understanding.

b. If you believe that some essential piece of information is missing, make an

appropriate assumption and use it to solve the problem.

c. Write all steps/instruction for a program, missing steps/instructions may lead to deduction of marks.

3. Exam is Closed Book. No handouts or extra material is allowed in exam hall other than rough sheet which will be provided by the examiner.

4. All the coding syntax will be based on NASM assembler.

5. No assembly software is allowed in the exam center

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For Teacher's use only Question 1 2 3 4 5 Total

Marks Question No: 1 ( Marks: 5 ) Write valid instruction(s) to perform each function specified below. [1x5] a. Provide instruction to jump to label BELOW if AL contains an even number.

b. Provide instruction to move the value at the top of the stack in IP register c. Provide instruction to move value of flag register in AX. d. Provide instruction to divide value of AX by 8. e. Provide instruction to store 0xFFFF into AX.

Question No: 2 ( Marks: 10 ) Implement the following code in assembly language. Assume that we are dealing in signed integers and try to write shorter code. [10]

if( BX>CX OR BX >VAL1 ) X=1

else X=2

Question No: 3 ( Marks: 10 ) Write a recursive function in assembly language to calculate the square of an integer by adding it in itself using recursive call. You can assume any integer number to calculate the square. [10] Question No: 4 ( Marks: 10 )

Give short answers to the following questions, each question carries equal marks. [2x5] a. What is the maximum memory 8088 can access? b. What is difference between logical and physical memory? c. A combination of 8 bits is called a byte. What is the name for 4 bits and for 16 bits? d. What is the purpose of direction flag? e. What is an assembly language directive?

Question No: 5 ( Marks: 10 ) What will be the value of AX after the execution of each instruction? [2x5] Each instruction is independent of others. If AX=44FF and BX=011F

a. xor ah, bh

b. ror bx, 2 c. not ah d. and ax, bx e. rcl ax, 2 if carry flag =0

cs401 collection of old papers

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