ADF4371_MODULUS1
val = (((u64)st->integer * ADF4371_MODULUS1) + st->fract1) * st->fpfd;
val += tmp + ADF4371_MODULUS1 / 2;
do_div(val, ADF4371_MODULUS1 * (1 << ref_div_sel));
tmp = tmp * ADF4371_MODULUS1;