Zq_mult
s32 t = Zq_mult(z, w->x[j + len]);
w->x[j + len] = Zq_mult(z, t - w->x[j + len]);
w->x[j] = Zq_mult(w->x[j], 41978);
Zq_mult(ws->a.x[n], ws->z[j].x[n]);
ws->tmp.x[j] -= Zq_mult(ws->c.x[j], ws->t1_scaled.x[j]);