Where am I going wrong in this MIPS code?

Question

So, i am new to MIPS and was writing a code for quadratic formula... I think i did everything right, but my program always give wrong answers and sometimes it aborts with Exception at PC 0x004000f8

please if anyone can tell me where I am going wrong and if there are any other discrepancy in my code, please guide. Thank you!

    .data
promptfora: .asciiz "Enter Value of a: "
promptforb: .asciiz "Enter Value of b: "
promptforc: .asciiz "Enter Value of c: "
finalansdisplay: .asciiz "root is:"
answer: .word 0



.text
.globl main
main:


#b in t1


li $v0, 4
la $a0, promptforb
syscall

li $v0, 5
syscall
move $t1, $v0



#a in t2


li $v0, 4
la $a0, promptfora
syscall

li $v0, 5
syscall
move $t2, $v0



#value of c in t3

li $v0, 4
la $a0, promptforc
syscall

li $v0, 5
syscall
move $t3, $v0



move $a0, $t1                          # pass arg's to function
jal power
move $t4, $v0                          #b^2

mul $t5,$t2,$t3                       # ac in t5

mul $t5,$t5,4

sub $a0,$t4,$t5                       # b^2 - 4ac

jal iSqrt


mul $t1,$t1,-1                   #- * b

add $t6,$t1,$v0                    # - b + sqrt(b^2 - 4ac)
 

mul $t2,$t2,2                      #2a 

div $t7, $t6,$t2                 #final root 


li $v0, 4
la $a0, finalansdisplay  
syscall

move $a0, $t6
li $v0, 1        #display final answer
syscall


li $v0, 10
syscall

.end main


#Function to square b

.globl power    
.ent power

power:

li $v0, 1

mul $v0, $a0, $a0

jr $ra
.end power


#Function for root


.globl iSqrt
.ent iSqrt
iSqrt:

move $v0, $a0 # $v0 = x = N

li $t0, 0 # counter
sqrLoop:

div $t1, $a0, $v0 # N/x

add $v0, $t1, $v0 # x + N/x

div $v0, $v0, 2 # (x + N/x)/2

add $t0, $t0, 1

blt $t0, 20, sqrLoop
jr $ra

.end iSqrt

Answer 1

try this and slightly change this for the other root you have to change something and how you do that is your test

.data
prompt: .asciiz "Enter number 1: "
prompt2: .asciiz "Enter number 2: "
prompt3: .asciiz "Enter number 3: "
newline: .asciiz "\n"
answer: .word 0
sqanswer:  .word 0
 
.text
.globl main
.ent main

main:
li $v0, 4
la $a0, prompt  
syscall

li $v0, 5
syscall
move $t1, $v0   

li $v0, 4
la $a0, prompt2   
syscall

li $v0, 5
syscall
move $t2, $v0     

li $v0, 4
la $a0, prompt3  
syscall

li $v0, 5
syscall
move $t3, $v0    

addi $a0, $t2, 0

#lw $a0, prompt
#lw $a1, prompt2
jal power

sw $v0, answer
lw $s0, answer 

li $t4, 4
mul $t5, $t1, $t3   
mul $t5, $t5, $t4   
li $t6, 2
mul $t7, $t6, $t1
sub $a1, $s0, $t5   

jal iSqrt

sw $v1, sqanswer
lw $s3, sqanswer 


li $s1, -1
mul $s1, $t2, $s1   
add $s2, $s1, $s3   
div $s3, $s2, $t7

move $a0, $s3
la $v0, 1
syscall 

li $v0, 10
syscall

.end main


.globl power
.ent power

power:

mul $v0, $a0, $a0

jr $ra

.end power

.globl iSqrt
.ent iSqrt

iSqrt:

move $v1, $a1   
li $t0, 0   

sqrLoop:

div $t8, $a1, $v1
add $v1, $t8, $v1
div $v1, $v1, 2 
add $t0, $t0, 1
blt $t0, 20, sqrLoop

jr $ra

.end iSqrt

Answer 2

Try this code!

.data

prompt: .asciiz "Enter valie for a :"
prompt2: .asciiz "Enter value for b:"
prompt3: .asciiz "Enter value for c:"

.text .globl main

main: li $v0,4 la $a0,prompt syscall

li $v0,5
syscall
move $t1, $v0

li $v0,4
la $a0,prompt2
syscall

li $v0,5
syscall
move $t2, $v0

li $v0,4
la $a0,prompt3
syscall

li $v0,5
syscall
move $t3, $v0    

move $a0,$t2
jal power
move $t0, $v0

mul $t3,$t3,4
mul $t3, $t3,$t1
sub $t0, $t0, $t3

move $a0,$t0
jal sqrt
move $t0, $v0

sub $t0, $t0,$t2
mul $t1, $t1, 2
div $t0, $t0, $t1

li $v0,1
move $a0,$t0
syscall

li $v0, 10
syscall
.end main   

power: mul $v0, $a0, $a0 jr $ra

.end power sqrt: move $v0, $a0 li $t5,0

sqrtloop: div $t6, $a0, $v0 add $v0,$t6,$v0 div $v0 $v0,2 add $t5,$t5,1 blt $t5, 20, sqrtloop jr $ra .end sqrt