tocc
OCNT(acs) = tocc(ccre - acs);
OCNT(acs) = tocc(ccre - acs);
OCNT(acs) = tocc(ccre - acs);
OCNT(cs) = tocc(ccre - cs); /* offset to next symbol */
OCNT(acs) = tocc(ccre - acs);
OCNT(ccre) = tocc(ccre - acs); /* make a back pointer */
OCNT(acs) = tocc(ccre - acs);