BIGN_S1_LEN
BIGN_S1_LEN(q_bit_len))
ret = nn_export_to_buf(&sig[l], (u16)BIGN_S1_LEN(q_bit_len), &s1); EG(ret, err);
ret = _reverse_endianness(&sig[l], (u16)BIGN_S1_LEN(q_bit_len));
ret = local_memcpy(&TMP[0], &sig[l], (u32)BIGN_S1_LEN(q_bit_len)); EG(ret, err);
ret = _reverse_endianness(&TMP[0], (u16)BIGN_S1_LEN(q_bit_len)); EG(ret, err);
ret = nn_init_from_buf(s1, &TMP[0], (u8)BIGN_S1_LEN(q_bit_len)); EG(ret, err);