-
Notifications
You must be signed in to change notification settings - Fork 0
/
freg.c
52 lines (42 loc) · 1.17 KB
/
freg.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
/*
* @Author: cpu_code
* @Date: 2020-07-22 20:55:46
* @LastEditTime: 2020-07-24 10:04:40
* @FilePath: \android_bottom\external\freg\freg.c
* @Gitee: https://gitee.com/cpu_code
* @Github: https://github.com/CPU-Code
* @CSDN: https://blog.csdn.net/qq_44226094
* @Gitbook: https://923992029.gitbook.io/cpucode/
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#define FREG_DEVICE_NAME "/dev/freg"
int main(int argc, char** argv)
{
int fd = -1;
int val = 0;
// 以读写方式打开设备文件/dev/freg
fd = open(FREG_DEVICE_NAME, O_RDWR);
if(fd == -1)
{
printf("Failed to open device %s.\n", FREG_DEVICE_NAME);
return -1;
}
printf("Read original value:\n");
// 读取它的内容,即读取虚拟硬件设备freg的寄存器val的内容
read(fd, &val, sizeof(val));
// 内容打印
printf("%d.\n\n", val);
val = 5;
printf("Write value %d to %s.\n\n", val, FREG_DEVICE_NAME);
// 将一个整数5写入到虚拟硬件设备freg的寄存器val中
write(fd, &val, sizeof(val));
printf("Read the value again:\n");
// 将这个整数5读取
read(fd, &val, sizeof(val));
//打印出来
printf("%d.\n\n", val);
close(fd);
return 0;
}