- return pio2_hi + pio2_lo;
- z = x*x;
- p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
- q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
- r = p/q;
- return pio2_hi - (x - (pio2_lo-x*r));
- } else if (hx < 0) { /* x < -0.5 */
- z = (one+x)*0.5;
- p = z*(pS0+z*(pS1+z*(pS2+z*(pS3+z*(pS4+z*pS5)))));
- q = one+z*(qS1+z*(qS2+z*(qS3+z*qS4)));
- s = sqrt(z);
- r = p/q;
- w = r*s-pio2_lo;
- return pi - 2.0*(s+w);
- } else { /* x > 0.5 */
- z = (one-x)*0.5;