quick verification of equivalence between Galois and Fibo representation

LFSR.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
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def lxor(a, b):
    if a == '0' and b == '0': return '0'
    if a == '1' and b == '0': return '1'
    if a == '0' and b == '1': return '1'
    if a == '1' and b == '1': return '0'
    return '?'

def bit_to_num(a):
    if a == '0': return 0
    if a == '1': return 1
    if a == '?': raise ValueError('Error: Converting unknown value to number')

def gen_bit(a):
    if a == 1: return '1'
    return '0'

def getbit(state, index):
    return state[index]

def setbit(state, index, value):
    state[index] = value

def print_state(state):
    print(''.join(state))



def multiplexer(state):
    getindex = bit_to_num(state[28])
    getindex += 2 * bit_to_num(state[25])
    getindex += 4 * bit_to_num(state[22])
    getindex += 8 * bit_to_num(state[19])
    return getindex + 1

def iterate(state):
    bit = state.pop()
    # x^30 + x^17 + x^16 + x^13 + x^11 + x^7 + x^5 + x^3 + x^2 + x + 1
    indexes = [1, 2, 3]
    for i in indexes:
        b = getbit(state, i)
        setbit(state, i, lxor(bit, b))
    state.insert(0, bit)
    return bit


def iterate2(state):
    bit = state.pop()
    ret = bit
    indexes = [0, 1, 2]
    for i in indexes:
        b = getbit(state, i)
        bit = lxor(bit, b)
    state.insert(0, bit)
    return ret


def roundf(state,iteratef):
    return iteratef(state)


def gen(iteratef):
    lfsr_state = ['1','0','0','0','0']
    print_state(lfsr_state)

    output=[]
    for x in range(15):
        b = roundf(lfsr_state,iteratef)
        if x % 5 == 0:
            print()
        print(b)

print("GALOIS")
gen(iterate)

print("FIBO")
gen(iterate2)