bin-stuffs.py

def to_bin(n):
  return bin(n)[2:] if n >= 0 else bin(n)[3:]

def to_int(b):
  return int(b, 2)

def ones_complement(b):
  return b.replace('1', '2').replace('0', '1').replace('2', '0')

def twos_complement(b):
  return to_bin(to_int(ones_complement(b)) + 1)

def sign_mag(n, num_bits=1):
  binary = to_bin(n)
  num_zeroes = (num_bits - len(binary)) - 1
  return '1' + ('0' * num_zeroes) + binary if n < 0 else '0' + ('0' * num_zeroes) + binary

def to_excess_m(n, m):
  return to_bin(n + m)

def from_excess_m(b, m):
  return to_int(b) - m