1-byte sequenceBecause different computer systems use different byte sequences to store data, the same 4-byte 32-bit integer is stored in memory in a different way. The byte order is divided into small tail byte sequence (Little endian) and large tail byte sequence (big endian), most of the Intel processor uses the small tail byte sequence, the Motorola processor most uses the big tail (large endian) byte order; Small tail is the low byte emissions at the lower end of memory, high byte emissions in the high-end memory. For example, a 4-byte integer with a value of 0x1234567 corresponds to a high or low byte:
| 01 |
23 |
45 |
67 |
| Byte3 |
Byte2 |
Byte1 |
Byte0 |
| High byte--à---------à--------------à low byte |
will be discharged in memory in the following order:
| Memory address serial Number |
Byte in-memory address |
16 in value |
| 0x03 |
Byte3 |
01 |
| 0x02 |
Byte2 |
23 |
| 0x01 |
Byte1 |
45 |
| 0x00 |
Byte0 |
67 |
The big tail is high byte emissions at the low end of memory, low byte emissions in the high-end memory. For example, a 4-byte integer with a value of 0x1234567 corresponds to a high or low byte:
| 01 |
23 |
45 |
67 |
| Byte3 |
Byte2 |
Byte1 |
Byte0 |
| High byte--à---------à--------------à low byte |
will be discharged in memory in the following order:
| Memory address serial Number |
Byte in-memory address |
16 in value |
| 0x03 |
Byte0 |
67 |
| 0x02 |
Byte1 |
45 |
| 0x01 |
Byte2 |
23 |
| 0x00 |
Byte3 |
01 |
2 network byte orderThe TCP/IP protocol defines the byte order as a large tail, so the byte order used in the TCP/IP protocol is often called the network byte order.
3 string in-memory storage (Intel series)
strings and integers are the opposite, and the index of the string is stored in memory from low to high; Char s[4] = "ABC";
| A |
B |
C |
/0 |
| S[0] |
S[1] |
S[2] |
S[3] |
|
will be discharged in memory in the following order:
| Memory address serial Number |
16 in value |
Position of the pointer p |
| 0xbffeadf7 |
/0 |
P+3 |
| 0xbffeadf6 |
C |
P+2 |
| 0xbffeadf5 |
B |
P+1 |
| 0xbffeadf4 |
A |
P |
int main (void) {char s[4] = "ABC"; char *p = s; printf ("%02x,%02x,%02x,%02x/n", &s[0], &s[1], &s[2], &s[3]); printf ("%02x,%02x,%02x,%02x/n", p, p+1, p+2, p+3); printf ("%
C, %
C, %
C, %
C/n ", S[0], s[1], s[2], s[3]); return 0; Output results: [netcool@hfinmsp2 demo]$./demo001 bffeadf4, Bffeadf5, &
