#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/io.h>
#include <stdint.h>
#include <string.h>


#define PORT_SPKR 0x61
#define PORT_CTRL 0x43
#define PORT_CH2  0x42

int main()
{
    unsigned char val;
    if (ioperm(PORT_CTRL, 1, 1) < 0 || ioperm(PORT_SPKR, 1, 1) < 0 || ioperm(PORT_CH2, 1, 1) < 0) {
        perror("Failed to request I/O port permission");
        return 1;
    }    

    // 设置timer2
    outb(0xB6, PORT_CTRL);

    // 设置频率
    outb(0x33, PORT_CH2);
    outb(0x05, PORT_CH2);

    // 打开speaker
    val = inb(PORT_SPKR);
    outb(val | 3, PORT_SPKR);

    // 响1秒
    sleep(1);

    // 关闭speaker
    outb(val, PORT_SPKR);

    return 0;
}