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 /* 10 * This is the CRC32c polynomial, as outlined by Castagnoli. 11 * x^32+x^28+x^27+x^26+x^25+x^23+x^22+x^20+x^19+x^18+x^14+x^13+x^11+x^10+x^9+ 12 * x^8+x^6+x^0 13 */ 14 #define CRC32C_POLY_LE 0x82F63B78 15 #define CRC32C_POLY_BE 0x1EDC6F41 16 17 /* How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. */ 18 /* For less performance-sensitive, use 4 */ 19 #ifndef CRC_LE_BITS 20 # define CRC_LE_BITS 64 21 #endif 22 #ifndef CRC_BE_BITS 23 # define CRC_BE_BITS 64 24 #endif 25 26 /* 27 * Little-endian CRC computation. Used with serial bit streams sent 28 * lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC. 29 */ 30 #if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \ 31 CRC_LE_BITS & CRC_LE_BITS-1 32 # error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}" 33 #endif 34 35 /* 36 * Big-endian CRC computation. Used with serial bit streams sent 37 * msbit-first. Be sure to use cpu_to_be32() to append the computed CRC. 38 */ 39 #if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \ 40 CRC_BE_BITS & CRC_BE_BITS-1 41 # error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}" 42 #endif 43 44 45 #define ___constant_swab32(x) \ 46 ((uint32_t)( \ 47 (((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \ 48 (((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \ 49 (((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) | \ 50 (((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24))) 51 52 53 #if (__GNUC__ >= 3) 54 #define likely(x) __builtin_expect(!!(x), 1) 55 #define unlikely(x) __builtin_expect(!!(x), 0) 56 #else 57 #define likely(x) (x) 58 #define unlikely(x) (x) 59 #endif 60
