lui     $s0,        0x4000
    addi    $s0,        $s0,            0x10
main_loop:
    addi    $s1,        $zero,          0x15b
    sw      $s1,        0($s0)
    # wait
    lui     $t0,        0xff
    addi    $t0,        $t0,            0xffff
wait_loop_1:
    addi    $t0,        $t0,            -1
    bgtz    $t0,        wait_loop_1

    addi    $s1,        $zero,          0x177
    sw      $s1,        0($s0)

    lui     $t0,        0xff
    addi    $t0,        $t0,            0xffff
wait_loop_2:
    addi    $t0,        $t0,            -1
    bgtz    $t0,        wait_loop_2
    j       main_loop