lib/crc32defs.h

   1 /*
   2  * There are multiple 16-bit CRC polynomials in common use, but this is
   3  * *the* standard CRC-32 polynomial, first popularized by Ethernet.
   4  * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0
   5  */
   6 #define CRCPOLY_LE 0xedb88320
   7 #define CRCPOLY_BE 0x04c11db7
   8
   9 /* How many bits at a time to use.  Valid values are 1, 2, 4, 8, and 32. */
  10 /* For less performance-sensitive, use 4 or 8 */
  11 #ifndef CRC_LE_BITS
  12 # define CRC_LE_BITS 32
  13 #endif
  14 #ifndef CRC_BE_BITS
  15 # define CRC_BE_BITS 32
  16 #endif
  17
  18 /*
  19  * Little-endian CRC computation.  Used with serial bit streams sent
  20  * lsbit-first.  Be sure to use cpu_to_le32() to append the computed CRC.
  21  */
  22 #if CRC_LE_BITS > 32 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
  23         CRC_LE_BITS & CRC_LE_BITS-1
  24 # error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32}"
  25 #endif
  26
  27 /*
  28  * Big-endian CRC computation.  Used with serial bit streams sent
  29  * msbit-first.  Be sure to use cpu_to_be32() to append the computed CRC.
  30  */
  31 #if CRC_BE_BITS > 32 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
  32         CRC_BE_BITS & CRC_BE_BITS-1
  33 # error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32}"
  34 #endif