ldexp.py

import math

def reinv_ldexp(x, n):
	b = 2 if n >= 0 else 1 / 2
	n *= -1 if n < 0 else 1
	a = int(n)
	while a > 0:
		if bool(a & 1):
			x *= b
		b *= b
		a = a >> 1
	return x

if __name__ == "__main__":
    print(reinv_ldexp(math.pi, 1.73))