zephyr/lib/os/crc8_sw.c

/*
 * Copyright (c) 2017 Nordic Semiconductor ASA
 * Copyright (c) 2015 Runtime Inc
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <sys/crc.h>

static const u8_t crc8_ccitt_small_table[16] = {
	0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15,
	0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d
};

u8_t crc8_ccitt(u8_t val, const void *buf, size_t cnt)
{
	int i;
	const u8_t *p = buf;

	for (i = 0; i < cnt; i++) {
		val ^= p[i];
		val = (val << 4) ^ crc8_ccitt_small_table[val >> 4];
		val = (val << 4) ^ crc8_ccitt_small_table[val >> 4];
	}
	return val;
}