little endian和big endian的概念解释,判定与用途

coldwarm

ittle endian:0xcdab3412,即0x00000000-0xcd,0x00000001-0xab,0x00000002-0x34,0x00000003-0x12

little endian把低位存放到高位

上面的说反了吧.little endian应当是
0x00000000-0x12
0x00000001-0x34
....
这样的吧.

little endian把低字节存放到低地址,把高字节放到高地址.
数据0xcdab3412从左到右,由高字节到低字节,由高地址到低地址.

1. 
   
2. #include <stdio.h>
   
3. #include <stdlib.h>
   
4. #include <unistd.h>
   
5. 
   
6. int main()
   
7. {
   
8.     int value = 0x12345678;
   
9. 
   
10.     union ValueT
    
11.     {
    
12.         int value;
    
13.         char data[4];
    
14.     } a;
    
15.     a.value = 0x12345678;
    
16.     printf("value is 0x%x\n", a.value);
    
17.     printf("address is %p, 0x%x\n",&a.data[0], a.data[0]);
    
18.     printf("address is %p, 0x%x\n",&a.data[1], a.data[1]);
    
19.     printf("address is %p, 0x%x\n",&a.data[2],  a.data[2]);
    
20.     printf("address is %p, 0x%x\n", &a.data[3], a.data[3]);
    
21. 
    
22.     exit(EXIT_SUCCESS);
    
23. }
    

复制代码

value is 0x12345678
address is 0xbffffa0c, 0x78
address is 0xbffffa0d, 0x56
address is 0xbffffa0e, 0x34
address is 0xbffffa0f, 0x12

[ 本帖最后由 coldwarm 于 2006-9-5 21:56 编辑 ]