EXTSPERSUM
bitno = extno & (EXTSPERSUM - 1);
bitno = extno & (EXTSPERSUM - 1);
mask = (bitno == 0) ? 0 : (ONES << (EXTSPERSUM - bitno));
if (rem >= EXTSPERSUM) {
if (rem >= EXTSPERSUM) {
bitno = extno & (EXTSPERSUM - 1);
mask = HIGHORDER >> (extno & (EXTSPERSUM - 1));
bitno = extno & (EXTSPERSUM - 1);