位操作函数

最新推荐文章于 2024-03-17 17:45:08 发布

liruijinking

最新推荐文章于 2024-03-17 17:45:08 发布

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CC 4.0 BY-SA版权

文章标签： input include 测试

本文链接：https://blog.youkuaiyun.com/liruijinking/article/details/2417995

本文介绍了一种位操作的实现方式，包括设置、清除和检查特定位的状态。通过定义宏和编写函数来完成位的设置与清除，并提供了一个测试函数来验证这些位操作的功能。

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#include <stdio.h>
#include <string.h>

#define PRESENT_BIT(x)   (0x00000001<<(x-1))
#define BIT_ON(m, b)   (((m) & PRESENT_BIT(b)) != 0)
#define SET_BIT(m, b)   ((m) |= PRESENT_BIT(b))
#define CLEAR_BIT(m, b)   ((m) &= ~PRESENT_BIT(b))

int set_bit(unsigned char *p_startAddr,unsigned int dw_bitLen,unsigned int dw_bitNum)
{
     if(!p_startAddr)
     {
         printf("no input parameter/n");
         return -1;
     }
    if(dw_bitNum >dw_bitLen || dw_bitNum<=0)
     {
         printf("dw_bitNum=%d, is larger than dw_bitLen=%d/n",dw_bitNum,dw_bitLen);
        return -1;
     }

     unsigned char uc_mask = 0x01;
     unsigned int dw_index = (unsigned int)((dw_bitNum-1)/8);
     unsigned char uc_bitter = (dw_bitNum-1)%8;
    p_startAddr[dw_index] = p_startAddr[dw_index] | (uc_mask << uc_bitter);

return 0;

}

int clear_bit(unsigned char *p_startAddr,unsigned int dw_bitLen,unsigned int dw_bitNum)
{
      if(!p_startAddr)
      {
          printf("no input parameter/n");
          return -1;
      }
     if(dw_bitNum >dw_bitLen || dw_bitNum<=0)
     {
         printf("dw_bitNum=%d, is larger than dw_bitLen=%d/n",dw_bitNum,dw_bitLen);
          return -1;
     }

     unsigned char uc_mask = 0x01;
     unsigned int dw_index = (unsigned int)((dw_bitNum-1)/8);
    unsigned char uc_bitter = (dw_bitNum-1)%8;
     p_startAddr[dw_index] = p_startAddr[dw_index] &(~(uc_mask << uc_bitter));

return 0;
}

int bit_on(unsigned char *p_startAddr,unsigned int dw_bitLen,unsigned int dw_bitNum)
{
      if(!p_startAddr)
      {
          printf(" no input parameter/n");
          return 0;
      }
     if(dw_bitNum >dw_bitLen || dw_bitNum<=0)
     {
         printf("dw_bitNum=%d, is or invalid, or larger than dw_bitLen=%d/n",dw_bitNum,dw_bitLen);
         return 0;
     }

     unsigned char uc_mask = 0x01;
     unsigned int dw_index = (unsigned int)((dw_bitNum-1)/8);
     unsigned char uc_bitter = (dw_bitNum-1)%8;
     unsigned char uc_result = p_startAddr[dw_index] &(uc_mask << uc_bitter);

return uc_result;
}

//位操作测试函数
void main()
{
     unsigned char uc_bitMap[100];
     memset(uc_bitMap,0,sizeof(uc_bitMap));

     int i;
     for(i=0;i<=sizeof(uc_bitMap)*8;i++)
     {
          if(bit_on(uc_bitMap,sizeof(uc_bitMap)*8,i))
           printf("bitNum %d is on/n",i);
     }

    set_bit(uc_bitMap,sizeof(uc_bitMap)*8,sizeof(uc_bitMap)*8);
    for(i=0;i<=sizeof(uc_bitMap)*8;i++)
    {
         if(bit_on(uc_bitMap,sizeof(uc_bitMap)*8,i))
         printf("bitNum %d is on/n",i);
     }

     clear_bit(uc_bitMap,sizeof(uc_bitMap)*8,sizeof(uc_bitMap)*8);
     for(i=0;i<=sizeof(uc_bitMap)*8;i++)
    {
         if(bit_on(uc_bitMap,sizeof(uc_bitMap)*8,i))
          printf("bitNum %d is on/n",i);
     }
}