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https://github.com/RfidResearchGroup/proxmark3.git
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a99c6a1921
the only reason any of the Windows code was in CPP files was because the MS compiler doesn't support C99. Switch to using MinGW, and that problem goes away, so we can rename the files back.
36 lines
1.3 KiB
C
36 lines
1.3 KiB
C
//-----------------------------------------------------------------------------
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// Routines to compute the CRCs (two different flavours, just for confusion)
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// required for ISO 14443, swiped directly from the spec.
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//-----------------------------------------------------------------------------
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#define CRC_14443_A 0x6363 /* ITU-V.41 */
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#define CRC_14443_B 0xFFFF /* ISO/IEC 13239 (formerly ISO/IEC 3309) */
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static unsigned short UpdateCrc14443(unsigned char ch, unsigned short *lpwCrc)
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{
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ch = (ch ^ (unsigned char) ((*lpwCrc) & 0x00FF));
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ch = (ch ^ (ch << 4));
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*lpwCrc = (*lpwCrc >> 8) ^ ((unsigned short) ch << 8) ^
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((unsigned short) ch << 3) ^ ((unsigned short) ch >> 4);
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return (*lpwCrc);
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}
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static void ComputeCrc14443(int CrcType, unsigned char *Data, int Length,
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unsigned char *TransmitFirst, unsigned char *TransmitSecond)
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{
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unsigned char chBlock;
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unsigned short wCrc=CrcType;
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do {
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chBlock = *Data++;
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UpdateCrc14443(chBlock, &wCrc);
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} while (--Length);
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if (CrcType == CRC_14443_B)
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wCrc = ~wCrc; /* ISO/IEC 13239 (formerly ISO/IEC 3309) */
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*TransmitFirst = (unsigned char) (wCrc & 0xFF);
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*TransmitSecond = (unsigned char) ((wCrc >> 8) & 0xFF);
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return;
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}
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