Question

Refer the program in the next page:

1. Assume the starting address of data segment: 0x10010000. What is the address of label num3?
   
   _______________________________
   
2. Write the common syscall code to print string for the blank marked as #Question 2

_________________________________

3. Write proper comments for the lines marked as #Question 3

________________________________________________________

4. Write the machine code for the line marked as #Question 4 in both binary and hex.

Binary:_______________________________________ Hex:___________________

5. Write the machine code for the line marked as #Question 5 in both binary and hex. Assume $t0 has the starting address of the data segment.

Binary:_______________________________________ Hex:___________________

6. Write the syscall code to exit the program for the blank marked as #Question 6

__________________________________

7. Describe what this program is doing in detail.

________________________________________________________________________________

8. Provide the memory address in which the character ‘t’ is stored.

____________________________________

# MIPS program for Questions

#

# ________________________________________________________________________________

#

# ________________________________________________________________________________

        .data

prompt:        .asciiz "The Number:"

Result:        .asciiz "The Result:"

num1:          .word   0

num2:          .word   0

num3:          .word   0

                         

        .globl main

        .text

main:

        ­­­­­­____________________           # Question 2

        la      $a0, prompt            #

        syscall                        #

        li      $v0, 5                 # Question 3

        syscall                        #

        sw      $v0, num1              #

       

        ­­­­­­____________________           # Question 2

        syscall                        #

        li      $v0, 5                 # Question 3

        syscall                        #

        sw      $v0, num2              #

        lw      $t1, num1              #

        lw      $t2, num2              #

        add     $t3, $t1, $t2          # Question 4

        sw      $t3, num3              # Question 5

        ____________________           # Question 2

        la      $a0, result            #

        syscall                        #

        lw      $a0, num3              #

        li      $v0, 1                 #

        syscall                        #

        ____________________           # Question 6

        syscall                        #

Answer 1

Question 1

Assume the starting address of data segment: 0x10010000. What is the address of label num3?

Ans) 0x10010020

Explanation:-

Start address 0x10010000.Then 'Prompt' label start that address.

It has 11 charcater so allocate 11 bytes space +null termination=12 bytes there

Next address 'Result' starts from 0x10010000+12=0x1001000c

It has 11 charcater so allocate 11 bytes space +null termination=12 bytes there

Next address' num1' starts from 0x1001000c+12=0x10010018

'num1' is word data type , so 4 bytes allocate

Next address' num2' starts from 0x10010018+4=0x1001001c

Next address' num2' starts from 0x1001001c+4=0x10010020

----------------------------------------------------------------------------------------------------------

Question 2

Write the common syscall code to print string for the blank marked as #Question 2

Ans) li $v0,4

Explanation:-

string print syscall in MIPS is li $v0,4 and syscall

------------------------------------------------------------------------------------------

Question 3

Write proper comments for the lines marked as #Question 3

Ans) Instruction read for read integer input and get the read data in v0 register

Explanation:-

In MIPS comments start with # , then comment in english

--------------------------------------------------------------------------------------------------------

Question 4

Write the machine code for the line marked as #Question 4 in both binary and hex.

Instruction:-

add     $t3, $t1, $t2

R-Type instruction format

opcode(6-bit)      rs(5-bit)     rt(5-bit)      rd(5-bit)    shampt(5-bit)    func(6-bit)

000000             01001        01010          01011           00000            100000

Binary code: 00000001001010100101100000100000

Hex: 0x012a5820

------------------------------------------------------------------------------

Question 5

Write the machine code for the line marked as #Question 5 in both binary and hex.

Instruction:-

sw      $t3, num3

I-Type instruction format

opcode(6-bit)      rs(5-bit)     rt(5-bit)        offset(16-bit)

101011               00000       01011           0000000000100000

Binary code: 10101100000010110000000000100000

Hex:0xac0b0020

------------------------------------------------------------------------------------------------

Question 6

Write the syscall code to exit the program for the blank marked as #Question 6

Ans) li $v0,10

Explanation:-

It is MIPS exit system call

----------------------------------------------------------------------

Question 7

Describe what this program is doing in detail.

#Data declaration section
             .data
prompt:        .asciiz "The Number:"
Result:        .asciiz "The Result:"
num1:          .word   0
num2:          .word   0
num3:          .word   0
#Program starts here
        .globl main
        .text
main:

       #Prompt for number1
       li $v0,4
       la      $a0, prompt         
        syscall                      
    #Read user input
        li      $v0, 5               
        syscall                     
#Store first number in variable num1
        sw      $v0, num1            
        syscall                     
       #Read num2 from user
        li      $v0, 5              
        syscall                      
        #Store second number in variable num2
        sw      $v0, num2
        #Get first number in t1         
        lw      $t1, num1            
         #Get first number in t2
        lw      $t2, num2
        #Add first and second number and store into t3           
        add     $t3, $t1, $t2       
        #Store sum,that is t3 value into memory num3
        sw      $t3, num3   
        #display reuslt prompt
        li $v0,4
        la      $a0, Result          
        syscall                      
       #Get sum from num3
        lw      $a0, num3            
       #Display sum
        li      $v0, 1               
        syscall                      
        #End of the program
        li $v0,10
        syscall

------------------------------------------------------------

Question 8

Provide the memory address in which the character ‘t’ is stored.

Ans)0x10010017

Explanation:

'Result ' starts at the address 0x1001000c

't' is the 11 the character, so 0x1001000c+11=0x10010017