33 lines
1 KiB
C
33 lines
1 KiB
C
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/*
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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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/* How many bits at a time to use. Requires a table of 4<<CRC_xx_BITS bytes. */
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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 8
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#endif
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#ifndef CRC_BE_BITS
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# define CRC_BE_BITS 8
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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 > 8 || CRC_LE_BITS < 1 || CRC_LE_BITS & CRC_LE_BITS-1
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# error CRC_LE_BITS must be a power of 2 between 1 and 8
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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 > 8 || CRC_BE_BITS < 1 || CRC_BE_BITS & CRC_BE_BITS-1
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# error CRC_BE_BITS must be a power of 2 between 1 and 8
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#endif
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