calc_crc32
return SWAP_BYTES32(calc_crc32((u8_t *)packet_buf, 8, seed, 0));
nwuf->crc32 = calc_crc32( nwuf->pattern, j, 0xffffffff /*seed*/, 1 /*complement*/ ) ;
u32_t calc_crc32(u8_t *crc32_packet, u32_t crc32_length, u32_t crc32_seed, u8_t complement);