crc_byte.c

Go to the documentation of this file.

/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <crc_byte.h>
 
uint8_t crc7_byte(uint8_t prev_crc, uint8_t data)
{
        const uint8_t g = 0x89;
        prev_crc ^= data;
        for (int i = 0; i < 8; i++) {
                if (prev_crc & 0x80)
                        prev_crc ^= g;
                prev_crc <<= 1;
        }
        return prev_crc;
}
 
uint16_t crc16_byte(uint16_t prev_crc, uint8_t data)
{
        prev_crc  = (uint8_t)(prev_crc >> 8)|(prev_crc << 8);
        prev_crc ^=  data;
        prev_crc ^= (uint8_t)(prev_crc & 0xff) >> 4;
        prev_crc ^= (prev_crc << 8) << 4;
        prev_crc ^= ((prev_crc & 0xff) << 4) << 1;
        return prev_crc;
}
 
uint32_t crc32_byte(uint32_t prev_crc, uint8_t data)
{
        prev_crc ^= (uint32_t)data << 24;
 
        for (int i = 0; i < 8; i++) {
                if ((prev_crc & 0x80000000UL) != 0)
                        prev_crc = ((prev_crc << 1) ^ 0x04C11DB7UL);
                else
                        prev_crc <<= 1;
        }
 
        return prev_crc;
}