bwn_nbits
static uint8_t bwn_nbits(int32_t);
CALC_COEFF(tmp[0], bwn_nbits(ie.ie_iqprod), ie.ie_iqprod, ie.ie_ipwr);
CALC_COEFF2(tmp[1], bwn_nbits(ie.ie_qpwr), ie.ie_qpwr, ie.ie_ipwr);