crc.lst

矿工定位系统单端

C51 COMPILER V7.05   CRC                                                                   04/08/2005 13:54:34 PAGE 1   


C51 COMPILER V7.05, COMPILATION OF MODULE CRC
OBJECT MODULE PLACED IN CRC.OBJ
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE CRC.C BROWSE DEBUG OBJECTEXTEND

stmt level    source

   1          
   2          #include "crc.h"
   3          #include<REG922.h>
   4          unsigned int code crc_ta[16]={
   5          0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
   6          0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef};/* CRC余式表 */
   7          
   8          unsigned int cal_crc(unsigned char  *ptr, unsigned char data  len)
   9          {
  10   1        unsigned int data crc;
  11   1        unsigned char data da;
  12   1        EA=0;
  13   1        crc=0;
  14   1        while(len--!=0)
  15   1        {
  16   2         da=((unsigned char)(crc/256))/16; /* 暂存CRC的高四位 */
  17   2         crc<<=4; /* CRC右移4位，相当于取CRC的低12位）*/
  18   2         crc^=crc_ta[da^(*ptr/16)]; /* CRC的高4位和本字节的前半字节相加后查表计算CRC；后加上上一次CRC的余数 */
  19   2         da=((unsigned char)(crc/256))/16; /* 暂存CRC的高4位 */
  20   2         crc<<=4; /* CRC右移4位， 相当于CRC的低12位） */
  21   2         crc^=crc_ta[da^(*ptr&0x0f)]; /* CRC的高4位和本字节的后半字节相加后查表计算CRC，
  22   2                                                                    然后再加上上一次CRC的余数 */
  23   2         ptr++;
  24   2         }
  25   1         EA=1;
  26   1      return(crc);
  27   1      }
  28          
  29          


MODULE INFORMATION:   STATIC OVERLAYABLE
   CODE SIZE        =    129    ----
   CONSTANT SIZE    =     32    ----
   XDATA SIZE       =   ----    ----
   PDATA SIZE       =   ----    ----
   DATA SIZE        =   ----       2
   IDATA SIZE       =   ----    ----
   BIT SIZE         =   ----    ----
END OF MODULE INFORMATION.


C51 COMPILATION COMPLETE.  0 WARNING(S),  0 ERROR(S)