Storage model: big end and small end

Preface ：

The information stored in the computer operating system is in bytes , Each address unit corresponds to 1 Bytes .

1 Bytes to 8 bits, For certain 32 For bit processors ,char Type data occupation 1 Bytes of space ,short Occupy 2 Bytes ,int Occupy 4 Bytes . And the storage order of these bytes in memory , And the arrangement of byte memory , It's all people's urgent concern . When the first byte appears , The second byte needs to determine its location and significance .

for example ,Internet agreement , for example RFC 791;

Another example is , File format , for example GIF、JPEG、MPEG wait .

And these bytes are in order one by one , Call it byte order (endianness). From left to right 、 From right to left , Byte order is divided into two ：

• Big endian byte order ;
• Small endian byte order ;

Detailed instructions ：

For a number x The value of is 0x2211, among 0x22 For high byte ,0x11 Is low byte .

For big end models , In the file 、 When the protocol is transmitted , In the order of reading , First, 0x22, Next is 0x11.

For the small end model , On the contrary , Will 0x22 Will then 0x11 after .

And in the computer , The big end model saves the high bytes of data in the low address of memory , The low byte of data is stored in the high address of memory . The small end model is the opposite .

For example, for numbers 0x1234567

When the computer processes byte order &#x