int getbits(hm2_sserial_tram_t *tram, u64 *val, int start, int len){
    long long user0 = (tram->reg_0_read == NULL)? 0 : *tram->reg_0_read;
    long long user1 = (tram->reg_1_read == NULL)? 0 : *tram->reg_1_read;
    long long user2 = (tram->reg_2_read == NULL)? 0 : *tram->reg_2_read;
    long long mask = (1 << len) - 1;

    if (start + len <= 32){
        *val = (user0 >> start) & mask;
    } else if (start + len <= 64){
        if (start >= 32){
            *val = (user1 >> (start - 32)) & mask;
        } else {
            *val = (((user1 << 32) | user0) >> start ) & mask;
        }
    } else {
        if (start >= 64){
            *val = (user2 >> (start - 64)) & mask;
        } else if (start >= 32) {
            *val = (((user2 << 32) | user1) >> (start - 32)) & mask;
        } else {
            *val = ((user2 << (64 - start)) | (user1 << (32 - start))
            | (user0 >> start)) & mask;
        }
    }
    return 0;
}