/* Increment the number of references to this object. It does not do a full copy.  */
bigint* ICACHE_FLASH_ATTR bi_copy(bigint *bi)
/* Increment the number of references to this object. It does not do a full copy.  */
bigint* ICACHE_FLASH_ATTR bi_copy(bigint *bi)
{
    check(bi);
    if (bi->refs != PERMANENT)
        bi->refs++;
    return bi;
}