bit endian & little endian

big endian & little endian(大端字节序和小端字节序)

假设:a=0x12345678;

则大端字节序和小端字节序的存储如下图所示：

                 Big-Endian                               Little-Endian

0字节            12h                                       78h

1字节            34h                                       56h

2字节            56h                                       34h

3字节            78h                                       21h

你也可以用下面的程序测验你的机器是大端字节序还是小端字节序：

#include <stdio.h>

int IsLittleEndian()
{
 unsigned int usData = 0x12345678;
 unsigned char *pucData = (unsigned char*)&usData;

 if(*pucData == 0x78)
 {
     return 1;
 }
 else
 {
     return 0;
 }

}

int main(void)
{
    
    if(IsLittleEndian())
    {
        printf("is little endian!\n");
    }
    else
    {
        printf("is big endian!\n");
    }

    return 0;
}