code: function pack (x, m) {
          for (var i = 0; i < UNPACKED_SIZE; ++i) {
              m[2 * i] = x[i] & 0x00FF;
              m[2 * i + 1] = (x[i] & 0xFF00) >> 8;
          }
      }
docs: /* Convert from internal format to little-endian byte format.  The
  number must be in a reduced form which is output by the following ops:
  unpack, mul, sqr
  set --  if input in range 0 .. P25
  If you're unsure if the number is reduced, first multiply it by 1.