BIT_LEN_ROUNDING
#define NN_USABLE_MAX_BYTE_LEN ((BIT_LEN_ROUNDING(NN_USABLE_MAX_BIT_LEN, 8)) / 8)
#define NN_USABLE_MAX_WORD_LEN ((BIT_LEN_ROUNDING(NN_USABLE_MAX_BIT_LEN, WORD_BITS)) / WORD_BITS)