MIPS program is finished running (dropped off bott

问题:

It's my first time doing MIPS assembly and I'm trying to create a program that (1) accepts user's input (2) pre-store it in a specific address (3) multiply using repeated addition

Here's my program:

  #Data Segment#
  .data 0x10010000
  x: .word  1988
  y: .word  1923

  .text
   #Main Segment
   main:
    sub    $t3, $t3, $t3            #initialize counter
    sub    $t4, $t4, $t4            #initialize product
    multiloop:
        lui    $t0, 0x1001
        lw     $t1, 0($t0)  #load first integer value; variable for addition
        lw     $t2, 4($t0)  #load second integer value; variable for counter
          sub    $t2, $t2, $t3  #counter operation
          bltz   $t2, done      #if counter > 0 means operation is complete
          add    $t4, $t4, $t1  #addition
          addi   $t3, $t3, 1    #increment counter
        j multiloop     #loop
   done:
    sw  $t4, 32($t0)  

The question is: why is my program " program is finished running (dropped off bottom)". Any help? Thanks!