Assignment 2

Note: Make reasonable assumptions where necessary and clearly state them. Feel free to

discuss problems with classmates, but the only written material that you may consult while

writing your solutions are the textbook and lecture slides/videos. Solutions should be

uploaded as a single pdf file on Canvas. Show your solution steps so you receive partial

credit for incorrect answers and we know you have understood the material. Don’t just

show us the final answer.

1. Annotate the following MIPS instructions to indicate source registers and destination

registers. A source register is read during the instruction’s execution, while a

destination register is written during the instruction’s execution. (12 points)

1. add $s1, $t2, $t3

2. lw $s3, 8($gp)

3. sw $s4, 12($s5)

4. addi $s1, $zero, 100

5. bne $t1, $t2, else

6. add $s1, $s1, $s1

2. Consider a program that declares global integer variables x, y[10]. These variables are

allocated starting at a base address of decimal 1000. All these variables have been

initialized to zero. The base address 1000 has been placed in $gp. The program

executes the following assembly instructions:

lw $s1, 0($gp)

addi $s1, $s1, 25

sw $s1, 0($gp)

lw $s2, 12($gp)

add $s2, $s2, $s1

sw $s2, 8($gp)

sw $s2, 12($gp)

1. What are the memory addresses of variables x, y[0], and y[1]? (15 points)

2. What are the values of variables x, y[0], y[1], and y[2] at the end of the program?

(20 points)

3. Express the following decimal number in binary and hexadecimal forms: 146. (6

points)

4. Express the following binary number in decimal and hexadecimal forms: 1001100. (6

points)

5. Express the following hexadecimal number in decimal and binary forms: 0x6d. (6

points)

6. Write the MIPS assembly code that corresponds to the pseudo code below. Assume

that the address for integer i is baseaddress+4 and the address for a[0] is

baseaddress+8. Assume that the baseaddress is stored in $gp. The code initializes i to

0; it then iterates from i=0 to i=9, setting a[i] = 4i in each iteration. To make your

code efficient, i must be loaded into a register at the start, and it must be updated in

memory only after you’ve finished the for loop.

for (i=0; i<10; i++)

2018/10/7 CS/EE 3810

http://www.cs.utah.edu/~rajeev/cs3810/hw/hw18-2.html 2/2

a[i] = 4*i;

(35 points)