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Commit | Line | Data |
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fdcc61d3 | 1 | #include "iso14443crc.h" |
2 | ||
3 | static unsigned short UpdateCrc14443(unsigned char ch, unsigned short *lpwCrc) | |
4 | { | |
5 | ch = (ch ^ (unsigned char) ((*lpwCrc) & 0x00FF)); | |
6 | ch = (ch ^ (ch << 4)); | |
7 | *lpwCrc = (*lpwCrc >> 8) ^ ((unsigned short) ch << 8) ^ | |
8 | ((unsigned short) ch << 3) ^ ((unsigned short) ch >> 4); | |
9 | return (*lpwCrc); | |
10 | } | |
11 | ||
12 | void ComputeCrc14443(int CrcType, | |
13 | unsigned char *Data, int Length, | |
14 | unsigned char *TransmitFirst, | |
15 | unsigned char *TransmitSecond) | |
16 | { | |
17 | unsigned char chBlock; | |
18 | unsigned short wCrc=CrcType; | |
19 | ||
20 | do { | |
21 | chBlock = *Data++; | |
22 | UpdateCrc14443(chBlock, &wCrc); | |
23 | } while (--Length); | |
24 | ||
25 | if (CrcType == CRC_14443_B) | |
26 | wCrc = ~wCrc; /* ISO/IEC 13239 (formerly ISO/IEC 3309) */ | |
27 | ||
28 | *TransmitFirst = (unsigned char) (wCrc & 0xFF); | |
29 | *TransmitSecond = (unsigned char) ((wCrc >> 8) & 0xFF); | |
30 | return; | |
31 | } |