static inline int chkmask(u128_t v) {
    /* this is sort of specialized */
    int i;
    u128_t m = u128_lit(~0ULL, ~0ULL);

    for(i = 0; i < 129; i++) {
        if(u128_cmp(v, m) == 0)
            return 1;
        m = u128_lsh(m, 1);
    }
    return 0;
}
static inline int chkmask(u128_t v) {
     
    int i;
    u128_t m = u128_lit(~0ULL, ~0ULL);

    for(i = 0; i < 129; i++) {
        if(u128_cmp(v, m) == 0)
            return 1;
        m = u128_lsh(m, 1);
    }
    return 0;
}