CRC16節(jié)約空間的計(jì)算方法

ID:332297 · 發(fā)表于 2018-5-17 17:05

// 計(jì)算CRC16的值
unsigned short CRC16(unsigned char *nData, unsigned short wLength)
{
  unsigned short static const CRC16tbl[16]={ // CRC余式表
0x0000,0xCC01,0xD801,0x1400,0xF001,0x3C00,0x2800,0xE401,
0xA001,0x6C00,0x7800,0xB401,0x5000,0x9C01,0x8801,0x4400
  };
  unsigned short wCRCWord=0xffff;
  unsigned char  da;
  while(wLength--)
  {
da = wCRCWord^*nData;
wCRCWord >>= 4;
wCRCWord ^= CRC16tbl[da&0x0f];
da = wCRCWord^((*nData)>>4);
wCRCWord >>= 4;
wCRCWord ^= CRC16tbl[da&0x0f];
nData++;
  }
  return wCRCWord;
}

ID:346116 · 發(fā)表于 2018-11-5 13:17

待校驗(yàn)的信息流
unsigned char c[] = {0x55,0xAA,0x00,0x01,0x04,0x15,0x00,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
用這個函數(shù)校驗(yàn)出來的結(jié)果是0x3c34，這是正確的。
其實(shí)我更想知道CRC16tbl[16]這張表示如何來的。

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CRC16節(jié)約空間的計(jì)算方法

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