Question

Part (c): An implementation of division

You are familiar with integer division operations. In some processors there is no

division instruction. One way to implement division is via repeated subtractions.

NB: This is integer division, NOT floating point division.

For example, consider the expression M / N where M = 370 and N = 120 . If we

repeatedly subtract until we have a value less than N , then the number of times we

do the subtraction is the result. Ie:

● 370 – 120 => 250 (subtraction #1)

● 250 – 120 => 130 (subtraction #2)

● 130 – 120 => 10 (subtraction #3)

When we have the result 10 , we have performed 3 subtractions. Therefore, 370 /

120 = 3

Your task for part (a) is to complete the code in division.asm that has been

provided for you. In that file there are some comments giving several simplifying

assumptions.

For example, the value M will always be a positive two’s-complement number; the

value N will always be a two’s complement positive number less than 128. For

greater certainty, N will never be 0 . Your code will not be tested with inputs that do

not meet these requirements.

Some test cases are provided to you.

# Compute M / N, where M must be in $8, N must be in $9,
# and M / N must be in $15.
# N will never be 0


.text
start:
        lw $8, testcase3_M
        lw $9, testcase3_N

# STUDENTS MAY MODIFY CODE BELOW
# vvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
        
        nop
        addi $15, $0, -10

# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# STUDENTS MAY MODIFY CODE ABOVE

exit:
        add $2, $0, 10
        syscall
                

.data

# testcase1: 370 / 120 = 3
#
testcase1_M:
        .word   370
testcase1_N:
        .word   120
        
# testcase2: 24156 / 77 = 313
#
testcase2_M:
        .word   24156
testcase2_N:
        .word   77
        
# testcase3: 33 / 120 = 0
#
testcase3_M:
        .word   33
testcase3_N:
        .word   120

Answer 1

Greetings!!

Code:

.data

prompt1: .asciiz "Please enter Divident"

prompt2: .asciiz "Please enter Divisor"

output: .asciiz "Quotient = "

.text

#display prompt1

la $a0,prompt1           #load the address of prompt1 message

li $v0,4                        #parameter for syscall for display string

syscall                         #display

#read divident

li $v0,5                        #parameter for syscall for read divident

syscall                         #read

move $t0,$v0              #store dividend in t0

#display prompt2

la $a0,prompt2           #load the address of prompt2 message

li $v0,4                        #parameter for syscall for display string

syscall                         #display

#read divisor

li $v0,5                        #parameter for syscall for read divisor

syscall                         #read

move $t1,$v0              #store divisor in t1

#multiplication

loop:

blt $t0,$t1,end             #if the divisor is less than dividend then go to end

sub $t0,$t0,$t1            #otherwise subtract divisor from the dividend and update divident

addi $t2,$t2,1              #increment the quotient value after one subtraction

j loop                           #repeat

end:

#display output          

la $a0,output               #load the address of the output message

li $v0,4                        #parameter for syscall for display output message

syscall                         #display

#display quotient

move $a0,$t2              #load the quotient into the register a0 for display

li $v0,1                        #parameter for display the quotient

syscall                         #display

#standard termination

li $v0,10                      #parameter for syscall for termination

syscall                         #stop execution

Output screenshots:

Testcase 1:

Testcase 2:

Testcase 3:

Hope this helps

Thank You