abs_diff
long long tmp, abs_expect, abs_diff, diff, tolerance = 0;
abs_diff = diff < 0 ? -diff : diff;
if (abs_diff < tolerance)
deviation = div64_u64(10000 * abs_diff(dco_freq, central_freq),
diff = abs_diff(freq2k * p * r2, LC_FREQ_2K * n2);
diff_best = abs_diff(freq2k * best->p * best->r2,