HIXWORD
#define XBIASED_EXP(x) ((((int *)&x)[HIXWORD] & ~0x80000000) >> 16)
#define XBIASED_EXP(x) (((int *)&x)[HIXWORD] & 0x7fff)
px[HIXWORD] = (px[HIXWORD] & ~XSGNMSK) | (py[HIXWORD] & XSGNMSK);
hx = ((int *) &x)[HIXWORD];