isqrtpi
return (isqrtpi * (p0 * cc - q0 * ss) / sqrt(x));
return (isqrtpi * (p0 * ss + q0 * cc) / sqrt(x));
t = isqrtpi * (p1 * cc - q1 * ss) / sqrt(x);
return (isqrtpi * (p1 * ss + q1 * cc) / sqrt(x));