src/lib/crc_byte.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <crc_byte.h>
   4
   5 uint8_t crc7_byte(uint8_t prev_crc, uint8_t data)
   6 {
   7         const uint8_t g = 0x89;
   8         prev_crc ^= data;
   9         for (int i = 0; i < 8; i++) {
  10                 if (prev_crc & 0x80)
  11                         prev_crc ^= g;
  12                 prev_crc <<= 1;
  13         }
  14         return prev_crc;
  15 }
  16
  17 uint16_t crc16_byte(uint16_t prev_crc, uint8_t data)
  18 {
  19         prev_crc  = (uint8_t)(prev_crc >> 8)|(prev_crc << 8);
  20         prev_crc ^=  data;
  21         prev_crc ^= (uint8_t)(prev_crc & 0xff) >> 4;
  22         prev_crc ^= (prev_crc << 8) << 4;
  23         prev_crc ^= ((prev_crc & 0xff) << 4) << 1;
  24         return prev_crc;
  25 }
  26
  27 uint32_t crc32_byte(uint32_t prev_crc, uint8_t data)
  28 {
  29         prev_crc ^= (uint32_t)data << 24;
  30
  31         for (int i = 0; i < 8; i++) {
  32                 if ((prev_crc & 0x80000000UL) != 0)
  33                         prev_crc = ((prev_crc << 1) ^ 0x04C11DB7UL);
  34                 else
  35                         prev_crc <<= 1;
  36         }
  37
  38         return prev_crc;
  39 }