Description

COE 301 COMPUTER ORGANIZATION
ICS 233: COMPUTER ARCHITECTURE & ASSEMBLY LANGUAGE
Major Exam 1

Time: 90 minutes, Total Pages:

Name:______________________________ ID:__________________ Section: _______

Notes:
• Do not open the exam book until instructed
• Answer all questions
• All steps must be shown
• Any assumptions made must be clearly stated

Question Max Points Score
Q1 22
Q2 14
Total 36

Dr. Aiman El-Maleh
Dr. Marwan Abu-Amara

[22 Points]
(Q1) Fill in the blank in each of the following questions:

(1) Assuming 12-bit signed 2’s complement representation, the binary number 1100 0000 0011 is equal to the decimal number _______________.

(2) Assuming 16-bit signed 2`s complement representation, the hexadecimal number FF00 is equal to the decimal number _______________.

(3) There is a one-to-one correspondence between assembly language and _____________ language.

(4) One main advantage of programming in ______________ language is that programs are portable.

(5) Accessing data from random access memory is slower than accessing it from __________ memory but faster than accessing it from _______________memory.

(6) ____________ RAM is slower than ___________ RAM but is denser and cheaper.

(7) Assuming variable Array is defined as shown below:

Array: .word 10, 11, 12, 13, 14

The content of register $t0 (in hexadecimal) after executing the following sequence of instructions is _____________.

la $t0, Array lw $t0, 4($t0)

(8) Given a magnetic disk with the following properties:

• Rotation speed = 7200 RPM (rotations per minute)
• Average seek = 8 ms, Sector = 512 bytes, Track = 200 sectors

The average rotational latency is ______ ms.

(9) The pseudo instruction ble $s2, 10, Next is implemented by the following minimum MIPS instructions:
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________

(10) The pseudo instruction ror $s0, $s0, 4 ($s0 is rotated to the right by 4 bits and stored in $s0) is implemented by the following minimum MIPS instructions:
__________________________________________________________________
__________________________________________________________________
__________________________________________________________________

(11) Assuming that $a0 contains an Alphabetic character, the instruction ____________________ will convert the character in $a0 from upper case to lower case and from lower case to upper case. Note that the ASCII code of character ‘A’ is 0x41 while that of character ‘a’ is 0x61.

(12) Assume that the instruction beq $t0, $t1, NEXT is at address 0x00400030 in the text segment, and the label NEXT is at address 0x00400014. Then, the value stored in the assembled instruction for the label NEXT is __________________.

(13) Assuming that variable Array is defined as shown below:

Array: .byte 1, -2, -3, 4

After executing the following sequence of instructions, the content of the three registers (in hexadecimal) is $t1=_______________, $t2=_______________, and $t3=_______________.
la $t0, Array lw $t1, 0($t0) lb $t2, 1($t0) lh $t3, 2($t0)

(14) Assuming the following data segment, and assuming that the first variable X is given the address 0x10010000, then the addresses for variables Y and Z will be _____________ and _____________.

.data
X: .byte 1, 2, 3
Y: .half 3, 4, 5
Z: .word 6, 7, 8

[14 Points]
(Q2) Write separate MIPS assembly code fragments with minimum instructions to implement each of the given requirements. You can use pseudo instructions in your solution.

(i) [5 points] Write a MIPS code fragment that computes the number of 0→1 and
1→0 transitions in the content of register $s0 and stores the result in register $s1.The content of register $s0 should be preserved. For example, if $s0=0x75 (=01110101 in binary), then $s1=5.

(ii) [4 points] Write a MIPS code fragment that computes the equation $s0 = $s0*105 without the use of multiplication instructions with the minimum number of instructions. HINT: 105=15*7.

(iii) [5 points] Given an array of words A with its base address stored in registers $s0, array size n stored in $s1, write the smallest MIPS assembly fragment for the following computation: Count=0;
for (i=0; i<n-1; i++)
if ( A[i]==A[i+1]) then Count++;

MIPS Instructions: