lfsr.py

#!/usr/bin/env python3

start_state = (1 << 11) | 1
lfsr = start_state
period = 0

for i in range(1023):
    print(f"{i:04d} {lfsr:-012b} {lfsr:-03x}")
    bit = (lfsr ^ (lfsr >> 1) ^ (lfsr >> 3) ^ (lfsr >> 8)) & 1
    lfsr = (lfsr >> 1) | (bit << 11)
    if start_state == lfsr:
        break

for i in range(1023):
    j = (1023 - i) % 1023
    print(f"{j:04d} {lfsr:-012b} {lfsr:-03x}")
    bit = (lfsr ^ (lfsr << 11) ^ (lfsr << 9) ^ (lfsr << 4)) & (1 << 11)
    lfsr = (lfsr << 1) & 0b111111111111 | (bit >> 11)
    if start_state == lfsr:
        break