60 lines
1.8 KiB
C
60 lines
1.8 KiB
C
/*
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* There are multiple 16-bit CRC polynomials in common use, but this is
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* *the* standard CRC-32 polynomial, first popularized by Ethernet.
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* 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
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*/
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#define CRCPOLY_LE 0xedb88320
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#define CRCPOLY_BE 0x04c11db7
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/*
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* This is the CRC32c polynomial, as outlined by Castagnoli.
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* 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+
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* x^8+x^6+x^0
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*/
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#define CRC32C_POLY_LE 0x82F63B78
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#define CRC32C_POLY_BE 0x1EDC6F41
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/* How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. */
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/* For less performance-sensitive, use 4 */
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#ifndef CRC_LE_BITS
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# define CRC_LE_BITS 64
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#endif
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#ifndef CRC_BE_BITS
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# define CRC_BE_BITS 64
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#endif
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/*
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* Little-endian CRC computation. Used with serial bit streams sent
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* lsbit-first. Be sure to use cpu_to_le32() to append the computed CRC.
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*/
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#if CRC_LE_BITS > 64 || CRC_LE_BITS < 1 || CRC_LE_BITS == 16 || \
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CRC_LE_BITS & CRC_LE_BITS-1
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# error "CRC_LE_BITS must be one of {1, 2, 4, 8, 32, 64}"
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#endif
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/*
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* Big-endian CRC computation. Used with serial bit streams sent
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* msbit-first. Be sure to use cpu_to_be32() to append the computed CRC.
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*/
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#if CRC_BE_BITS > 64 || CRC_BE_BITS < 1 || CRC_BE_BITS == 16 || \
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CRC_BE_BITS & CRC_BE_BITS-1
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# error "CRC_BE_BITS must be one of {1, 2, 4, 8, 32, 64}"
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#endif
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#define ___constant_swab32(x) \
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((uint32_t)( \
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(((uint32_t)(x) & (uint32_t)0x000000ffUL) << 24) | \
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(((uint32_t)(x) & (uint32_t)0x0000ff00UL) << 8) | \
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(((uint32_t)(x) & (uint32_t)0x00ff0000UL) >> 8) | \
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(((uint32_t)(x) & (uint32_t)0xff000000UL) >> 24)))
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#if (__GNUC__ >= 3)
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#define likely(x) __builtin_expect(!!(x), 1)
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#define unlikely(x) __builtin_expect(!!(x), 0)
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#else
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#define likely(x) (x)
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#define unlikely(x) (x)
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#endif
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