crc8.c 489 B

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (c) 2013 Google, Inc
  4. */
  5. #include "linux/crc8.h"
  6. #define POLY (0x1070U << 3)
  7. static unsigned char _crc8(unsigned short data)
  8. {
  9. int i;
  10. for (i = 0; i < 8; i++) {
  11. if (data & 0x8000)
  12. data = data ^ POLY;
  13. data = data << 1;
  14. }
  15. return (unsigned char)(data >> 8);
  16. }
  17. unsigned int crc8(unsigned int crc, const unsigned char *vptr, int len)
  18. {
  19. int i;
  20. for (i = 0; i < len; i++)
  21. crc = _crc8((crc ^ vptr[i]) << 8);
  22. return crc;
  23. }