fast Fibonacci numbers / builtin µs timing code made platform independent (python[23] / Pico MicroPython)

fib.py

from sys import platform

if platform=='rp2':
    from time import ticks_us as default_timer
    def delta(t0,t1):
        return t1-t0
else:
    from timeit import default_timer
    def delta(t0,t1):
        return int(1000000*(t1-t0)+0.5)

def calc(t, odd):
    return ((t[1]**2 +     t[0]**2   ), (t[1]**2 + 2*t[0]*t[1])) if odd\
      else ((t[1]**2 - (t[1]-t[0])**2), (t[1]**2 +   t[0]**2  ))

def fib(n):
    if n==0:
        return (0, 1)
    elif n==1:
        return (1, 1)
    else:
        return calc(fib(n//2), n%2 == 1)
    
def Ffast(n):
    return fib(n)[0]

def F(n):
    a=0
    b=1
    for i in range(0,n):
        n=a+b
        a=b
        b=n
    return a

def tst(N, pF=True):
    for n in range(N-9, 1+N):
        start=default_timer()
        r=F(n)
        stop=default_timer()
        r2=Ffast(n)
        stop2=default_timer()
        print(r if pF else len(str(r)), delta(start,stop), r==r2, delta(stop,stop2))

print(delta(default_timer(),default_timer()))