div_q
term = mult_q(term, div_q(x, 1 << PSC_Q_FRACTION));
term = mult_q(term, div_q(x, 2 << PSC_Q_FRACTION));
term = mult_q(term, div_q(x, 3 << PSC_Q_FRACTION));
term = mult_q(term, div_q(x, 4 << PSC_Q_FRACTION));
sigma_q = div_q(PSC_Q_ROUND_OFFSET, fc_q);
g1_q = exp_approx_q(div_q(-PSC_Q_ROUND_OFFSET,
fc_q = div_q(1, PSC_NUM_PHASES);
fc_q = div_q(dst_length, src_length * PSC_NUM_PHASES);