My assembler code has this error: "invalid program counter value: 0x00000000 Go: execution terminated with errors" - mips

Question

.data
prompt2: .asciiz "please enter the elements one by one:"
prompt3: .asciiz "the array is ordered as follows: "
prompt4: .asciiz "-- Program is finished running --"
str1: .asciiz ","
newLine: .asciiz "\n"
.text
addi $sp,$sp,-24
sw $ra,0($sp)
sw $s4,4($sp)
sw $a2,8($sp)
sw $s3,12($sp)
sw $s0,16($sp)
sw $s2,20($sp)
main:
# read n from console
li $v0 5
syscall
move $a2 $v0 #tagghiir t0 be a2 (n)
# allocate dynamic memory
sll $a0 $v0 2 # sll performs $a0 = $v0 x 2^2
li $v0 9 #9 is the system code for service(sbrk) whoes work is
syscall #to allocate dynamic memory
move $a1 $v0 #t2 saved address of heap #taghiir t2 to a1
#saved for printing
li $v0, 4 # $system call code for print_str
la $a0, prompt2 # $address of string to print
syscall
move $t1 $zero
move $t4,$a1
inputLoop:
bge $t1 $a2 exit1
# read in and store int
li $v0 5
syscall
sw $v0 0($t4)
addi $t1 $t1 1
addi $t4 $t4 4
li $v0, 4 # $system call code for print_str
la $a0, newLine # $address of string to print
syscall
j inputLoop
exit1:
jal sort
li $v0, 4 # $system call code for print_str
la $a0, prompt3 # $address of string to print
syscall
move $t3,$zero
move $t4 ,$a1
outputLoop:
bge $t3 $a2 exit2
#inaro azoon yki copy krdm
lw $t6, 0($t4)
li $v0, 1
move $a0, $t6
syscall
# read in and store int
addi $t3 $t3 1
addi $t4 $t4 4
blt $t4,$a1 ,comma
# bne $t5,$zero,comma
comma:
li $v0, 4 # $system call code for print_str
la $a0, str1 # $address of string to print
syscall
j outputLoop
exit2:
li $v0, 10
syscall #for finishing the program
swap:
move $a3,$a3
move $a1,$s4
# move $t5,$zero # its for our temp variable in c code
move $t4 ,$a1 #t4 is now the base address of heap
sll $t6 , $a3,2 # s1 is the given k
add $t6,$t4,$t6 # heap address + k*4
lw $t3,0($t6) #khoone k e heap
lw $t5,4($t6) #khoone k+1 heap
sw $t5,0($t6)
sw $t3,4($t6)
jr $ra
sort:
# move $s0,$zero #i=t0
move $s4,$a1 #base address of heap
addi $t5,$a2,-1 # meghdare i
move $s2,$zero #its the flag
while:
addi $s2,$s2,1
move $a3,$zero #j #taghiir s1 be a3 (haman j va k
forLoop:
bge $a3,$t5,outOfLoop
sll $t6,$a3,2 #j
add $t1,$t6,$a1 #v+j
lw $t7,0($t1) #t7=heap[j]
lw $t8,4($t1) #t8=heap[j+1]
blt $t7,$t8,outOfIf
move $s4,$a1
move $s3,$a3
jal swap
addi $s2,$s2,-1
outOfIf:
addi $a3,$a3,1 #j++
outOfLoop:
addi $t5,$t5-1 #i--
bgt $s2,$zero,exit_outter #if a>=b break
ble $t5,$zero,exit_outter #if b=< c break
j while
exit_outter:
lw $ra,0($sp)
lw $s4,4($sp)
lw $a2,8($sp)
lw $s3,12($sp)
lw $s0,16($sp)
lw $s2,20($sp)
addi $sp,$sp,24
jr $ra
Where am I going wrong?