CRC校验的C实现代码

#define crc_mul 0x1021    /*生成多项式*/

unsigned int cal_crc(unsigned char *ptr,unsigned char len) {
  unsigned char i;
  unsigned int crc=0;
  while(len--!=0) {
    for(i=0x80; i!=0; i/=2) {
      if((crc&0x8000)!=0) {crc*=2; crc^=crc_mul;}   /* 余式CRC乘以2再求CRC  */
        else crc*=2;
      if((*ptr&i)!=0) crc^=crc_mul;                /* 再加上本位的CRC */
    }
    ptr++;
  }
  return(crc);
}

 /*测试代码*/
main()
{
  unsigned char i[8] = { 0x00,0x00,0x00,0x00,0x06,0x0d,0xd2,0xe3};/*{0x12,0x23,0xa5,0x86,0x07};*/
  unsigned int crc;
  crc=cal_crc(&i,8);
  printf("%x",crc);
  getch();
}