103 lines
3.3 KiB
C
103 lines
3.3 KiB
C
/* CRC compatibility, adapted from the Teensy 3 core at:
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https://github.com/PaulStoffregen/cores/tree/master/teensy3
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which was in turn adapted by Paul Stoffregen from the C-only comments here:
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http://svn.savannah.nongnu.org/viewvc/trunk/avr-libc/include/util/crc16.h?revision=933&root=avr-libc&view=markup */
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/* Copyright (c) 2002, 2003, 2004 Marek Michalkiewicz
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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#ifndef _UTIL_CRC16_H_
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#ifdef ARDUINO_ARCH_AVR
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#include <util/crc16.h>
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#else
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#define _UTIL_CRC16_H_
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#include <stdint.h>
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static inline uint16_t _crc16_update(uint16_t crc, uint8_t data) __attribute__((always_inline, unused));
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static inline uint16_t _crc16_update(uint16_t crc, uint8_t data)
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{
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unsigned int i;
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crc ^= data;
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for (i = 0; i < 8; ++i) {
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if (crc & 1) {
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crc = (crc >> 1) ^ 0xA001;
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} else {
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crc = (crc >> 1);
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}
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}
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return crc;
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}
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static inline uint16_t _crc_xmodem_update(uint16_t crc, uint8_t data) __attribute__((always_inline, unused));
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static inline uint16_t _crc_xmodem_update(uint16_t crc, uint8_t data)
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{
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unsigned int i;
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crc = crc ^ ((uint16_t)data << 8);
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for (i=0; i<8; i++) {
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if (crc & 0x8000) {
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crc = (crc << 1) ^ 0x1021;
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} else {
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crc <<= 1;
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}
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}
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return crc;
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}
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static inline uint16_t _crc_ccitt_update (uint16_t crc, uint8_t data) __attribute__((always_inline, unused));
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static inline uint16_t _crc_ccitt_update (uint16_t crc, uint8_t data)
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{
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data ^= (crc & 255);
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data ^= data << 4;
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return ((((uint16_t)data << 8) | (crc >> 8)) ^ (uint8_t)(data >> 4)
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^ ((uint16_t)data << 3));
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}
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static inline uint8_t _crc_ibutton_update(uint8_t crc, uint8_t data) __attribute__((always_inline, unused));
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static inline uint8_t _crc_ibutton_update(uint8_t crc, uint8_t data)
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{
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unsigned int i;
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crc = crc ^ data;
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for (i = 0; i < 8; i++) {
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if (crc & 0x01) {
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crc = (crc >> 1) ^ 0x8C;
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} else {
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crc >>= 1;
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}
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}
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return crc;
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}
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#endif
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#endif
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