MIPS filling a variable size array - arrays

Question

For some reason the integer values i'm putting into memory of the array of base $t0 cant be accessed later on even though when debugging i can clearly see that they are stored correctly in memory at 0($t0) and 4($t0) in the case of 2 integers. Its when i go into the passloop and attempt to load them into t6 or t7 that no value is being passed. Can someone explain why this is?
# bubble sort
.data
prompt1: .asciiz "Enter the array size \n"
prompt2: .asciiz "Enter integers to fill the array \n"
prompt3: .asciiz "Sorted Array: "
.text
.globl main
main:
la $a0, prompt1
li $v0, 4
syscall
li $v0, 5
syscall
add $t1, $zero, $v0
add $t2, $zero, $v0
sll $a0, $v0, 2
li $v0, 9
syscall
add $t0, $zero, $v0
loop:
la $a0, prompt2
li $v0, 4
syscall
li $v0, 5
syscall
beqz $t1, mainloop
sw $v0, ($t0)
addiu $t0, $t0, 4
subiu $t1, $t1, 1
bnez $t1, loop
mainloop:
subi $a1,$t2,1
blez $a1,done
li $t3,0
jal passloop
beqz $t3,done
subi $t2,$t2,1
j mainloop
#print sorted data, code still needed. Need to fix accessing issue first
done:
j end
passloop:
lw $t6,0($t0)
lw $t7,4($t0)
bgt $t6,$t7,swap
next:
addiu $t0,$t0,4
subiu $a1,$a1,1
bgtz $a1,passloop
jr $ra
swap:
sw $t6,4($t0)
sw $t7,0($t0)
li $t3,1
j next
end:
li $v0,10
syscall