_start: 
    li  x1, 0
    li  x2, 1
    li  x3, 0
    li  x4, 0
    li  x5, 32
fib:
    add x3, x1, x2
    mv  x1, x2
    mv  x2, x3
    add x4, x4, 1
    bne x4, x5, fib