module BinData::Int

def pack_directive(nbits, endian)
  bits_per_word = bytes_per_word(nbits) * 8
  nwords        = nbits / bits_per_word
  if (nbits % 32).zero?
    d = (endian == :big) ? 'N' : 'V'
  elsif (nbits % 16).zero?
    d = (endian == :big) ? 'n' : 'v'
  else
    d = 'C'
  end
  d * nwords
end