XSGNMSK
#define ISZEROL(x) (((((int *)&x)[0] & ~XSGNMSK) | ((int *)&x)[1] | \
px[n0] = py[n0] & XSGNMSK;
if ((px[n0] & XSGNMSK) == 0) { /* x > 0.0 */
px[HIXWORD] = (px[HIXWORD] & ~XSGNMSK) | (py[HIXWORD] & XSGNMSK);
px[n0] = py[n0] & XSGNMSK;
if ((px[n0] & XSGNMSK) == 0) { /* x > 0.0 */
px[n0] = py[n0] & XSGNMSK;
if ((px[n0] & XSGNMSK) == 0) { /* x > 0.0 */