ln2_hi
hi = x - ln2_hi;
hi = x + ln2_hi;
hi = x - t * ln2_hi; /* t*ln2_hi is exact here */
return (k * ln2_hi + c);
return (k * ln2_hi - ((R - (k * ln2_lo + c)) - f));
return (k * ln2_hi - ((hfsq - (s * (hfsq + R) +