SLIWIN_WORDS
SLIWIN_TYPE B[SLIWIN_WORDS];
for (k = 0; k < MIN(j - i, SLIWIN_WORDS); k++)
W->B[(i + k + 1) % SLIWIN_WORDS] = 0;
word = (S / SLIWIN_BPW) % SLIWIN_WORDS;