OCNT
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
OCNT(cs) = ccre - cs; /* offset to next symbol */
temp = OCNT(acs);
OCNT(acs) = ccre - acs;
OCNT(ccre) = ccre - acs; /* make a back pointer */
OCNT(ccre) = 0;
temp = OCNT(acs);
OCNT(acs) = ccre - acs;