* libs/libc/misc/lib_crc16h1021.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
* based on the CCITT-FALSE CRC16 Standard.
*
* CRC16 parameters:
* CRC result width: 16 bits
* Polynomial: 1021h
* Initial value: FFFFh
* Input data reflected: No
* Result data reflected: No
* XOR value: 0000h
*
* [AUTOSAR_SWS_Crc_00054] The Crc_CalculateCRC16 function of the CRC module
* shall provide the following CRC results:
*
* Data bytes (hexadecimal) | CRC
* 00 00 00 00 | 84C0
* F2 01 83 | D374
* 0F AA 00 55 | 2023
* 00 FF 55 11 | B8F9
* 33 22 55 AA BB CC DD EE FF | F53F
* 92 6B 55 | 0745
* FF FF FF FF | 1D0F
*/
* Included Files
****************************************************************************/
#include <sys/types.h>
#include <stdint.h>
#include <nuttx/crc16.h>
* Private Data
****************************************************************************/
* CRC16 table generated with:
*
* #include <stdint.h>
*
* void generate_crc16_table(uint16_t poly, uint16_t *table)
* {
* for (int i = 0; i < 256; i++)
* {
* uint16_t crc = (uint16_t)(i << 8);
* for (uint8_t bit = 0; bit < 8; bit++)
* {
* if (crc & 0x8000)
* {
* crc = (crc << 1) ^ polynomial;
* }
* else
* {
* crc = crc << 1;
* }
* }
* crcTable[i] = crc;
* }
* }
*
* int main()
* {
* uint16_t crc16_table[256];
* const uint8_t poly = 0x2F;
*
* generate_crc16_table(poly, crc16_table);
*
* printf("CRC16 Static Table (Poly 0x%02X):\n", poly);
* for (int i = 0; i < 256; i++)
* {
* if (i % 16 == 0) printf("\n");
* printf("0x%02X, ", crc16_table[i]);
* }
*
* return 0;
* }
*
****************************************************************************/
* Public Functions
****************************************************************************/
* Name: crc16h1021_part
*
* Description:
* Continue CRC calculation on a part of the buffer
* using the 0x1021 polynomial.
*
****************************************************************************/
uint16_t crc16h1021_part(FAR const uint8_t *src,
size_t len, uint16_t crc16val)
{
size_t i;
static const uint16_t g_crc16_tab[256] =
{
0x0000u, 0x1021u, 0x2042u, 0x3063u, 0x4084u, 0x50a5u, 0x60c6u, 0x70e7u,
0x8108u, 0x9129u, 0xa14au, 0xb16bu, 0xc18cu, 0xd1adu, 0xe1ceu, 0xf1efu,
0x1231u, 0x0210u, 0x3273u, 0x2252u, 0x52b5u, 0x4294u, 0x72f7u, 0x62d6u,
0x9339u, 0x8318u, 0xb37bu, 0xa35au, 0xd3bdu, 0xc39cu, 0xf3ffu, 0xe3deu,
0x2462u, 0x3443u, 0x0420u, 0x1401u, 0x64e6u, 0x74c7u, 0x44a4u, 0x5485u,
0xa56au, 0xb54bu, 0x8528u, 0x9509u, 0xe5eeu, 0xf5cfu, 0xc5acu, 0xd58du,
0x3653u, 0x2672u, 0x1611u, 0x0630u, 0x76d7u, 0x66f6u, 0x5695u, 0x46b4u,
0xb75bu, 0xa77au, 0x9719u, 0x8738u, 0xf7dfu, 0xe7feu, 0xd79du, 0xc7bcu,
0x48c4u, 0x58e5u, 0x6886u, 0x78a7u, 0x0840u, 0x1861u, 0x2802u, 0x3823u,
0xc9ccu, 0xd9edu, 0xe98eu, 0xf9afu, 0x8948u, 0x9969u, 0xa90au, 0xb92bu,
0x5af5u, 0x4ad4u, 0x7ab7u, 0x6a96u, 0x1a71u, 0x0a50u, 0x3a33u, 0x2a12u,
0xdbfdu, 0xcbdcu, 0xfbbfu, 0xeb9eu, 0x9b79u, 0x8b58u, 0xbb3bu, 0xab1au,
0x6ca6u, 0x7c87u, 0x4ce4u, 0x5cc5u, 0x2c22u, 0x3c03u, 0x0c60u, 0x1c41u,
0xedaeu, 0xfd8fu, 0xcdecu, 0xddcdu, 0xad2au, 0xbd0bu, 0x8d68u, 0x9d49u,
0x7e97u, 0x6eb6u, 0x5ed5u, 0x4ef4u, 0x3e13u, 0x2e32u, 0x1e51u, 0x0e70u,
0xff9fu, 0xefbeu, 0xdfddu, 0xcffcu, 0xbf1bu, 0xaf3au, 0x9f59u, 0x8f78u,
0x9188u, 0x81a9u, 0xb1cau, 0xa1ebu, 0xd10cu, 0xc12du, 0xf14eu, 0xe16fu,
0x1080u, 0x00a1u, 0x30c2u, 0x20e3u, 0x5004u, 0x4025u, 0x7046u, 0x6067u,
0x83b9u, 0x9398u, 0xa3fbu, 0xb3dau, 0xc33du, 0xd31cu, 0xe37fu, 0xf35eu,
0x02b1u, 0x1290u, 0x22f3u, 0x32d2u, 0x4235u, 0x5214u, 0x6277u, 0x7256u,
0xb5eau, 0xa5cbu, 0x95a8u, 0x8589u, 0xf56eu, 0xe54fu, 0xd52cu, 0xc50du,
0x34e2u, 0x24c3u, 0x14a0u, 0x0481u, 0x7466u, 0x6447u, 0x5424u, 0x4405u,
0xa7dbu, 0xb7fau, 0x8799u, 0x97b8u, 0xe75fu, 0xf77eu, 0xc71du, 0xd73cu,
0x26d3u, 0x36f2u, 0x0691u, 0x16b0u, 0x6657u, 0x7676u, 0x4615u, 0x5634u,
0xd94cu, 0xc96du, 0xf90eu, 0xe92fu, 0x99c8u, 0x89e9u, 0xb98au, 0xa9abu,
0x5844u, 0x4865u, 0x7806u, 0x6827u, 0x18c0u, 0x08e1u, 0x3882u, 0x28a3u,
0xcb7du, 0xdb5cu, 0xeb3fu, 0xfb1eu, 0x8bf9u, 0x9bd8u, 0xabbbu, 0xbb9au,
0x4a75u, 0x5a54u, 0x6a37u, 0x7a16u, 0x0af1u, 0x1ad0u, 0x2ab3u, 0x3a92u,
0xfd2eu, 0xed0fu, 0xdd6cu, 0xcd4du, 0xbdaau, 0xad8bu, 0x9de8u, 0x8dc9u,
0x7c26u, 0x6c07u, 0x5c64u, 0x4c45u, 0x3ca2u, 0x2c83u, 0x1ce0u, 0x0cc1u,
0xef1fu, 0xff3eu, 0xcf5du, 0xdf7cu, 0xaf9bu, 0xbfbau, 0x8fd9u, 0x9ff8u,
0x6e17u, 0x7e36u, 0x4e55u, 0x5e74u, 0x2e93u, 0x3eb2u, 0x0ed1u, 0x1ef0u
};
for (i = 0u; i < len; i++)
{
crc16val = g_crc16_tab[((crc16val >> 8) & 0xffu) ^
src[i]] ^ (uint16_t)(crc16val << 8);
}
return crc16val;
}
* Name: crc16h1021
*
* Description:
* Return a 16-bit CRC of the contents of the 'src' buffer, length 'len'
* using the 0x1021 polynomial.
*
****************************************************************************/
uint16_t crc16h1021(FAR const uint8_t *src, size_t len)
{
return crc16h1021_part(src, len, 0xffffu);
}