unsigned char *last_page = pages + maxpage - minpage;
unsigned char *last_page = pages + (maxpage - minpage) + 1;
decay(){    unsigned char *page = pages;    unsigned char *last_page = pages + maxpage - minpage;    for (; page < last_page; ++page) {        if (*page) {            *page /= 8;            *page *= 7;        }    }}