用龙芯系统写一个按键中断流水灯系统

好的，以下是一个简单的按键中断流水灯系统代码，使用龙芯系统的C语言编写：

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>

#define GPIO_DATA_OFFSET 0x00
#define GPIO_TRI_OFFSET 0x04
#define GPIO_DATAIN_OFFSET 0x10
#define GPIO_INTEN_OFFSET 0x30
#define GPIO_INTMASK_OFFSET 0x34
#define GPIO_INTTYPE_LEVEL_OFFSET 0x38
#define GPIO_INT_POLARITY_OFFSET 0x3C
#define GPIO_INT_STATUS_OFFSET 0x40

#define LED_COUNT 8
#define LED_DELAY 200000

volatile unsigned int *gpio;

void setup_gpio() {
    int fd;

    fd = open("/dev/mem", O_RDWR);
    if (fd < 0) {
        perror("open /dev/mem failed");
        exit(1);
    }

    gpio = (unsigned int *)mmap(NULL, 0x1000, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x18040000);
    if (gpio == MAP_FAILED) {
        perror("mmap failed");
        exit(1);
    }

    close(fd);

    // Configure LED pins as outputs
    *gpio |= (0xff << 16);

    // Configure button pin as input
    *gpio &= ~(1 << 4);

    // Enable interrupt for button pin
    *(gpio + GPIO_INTMASK_OFFSET/4) &= ~(1 << 4);
    *(gpio + GPIO_INTTYPE_LEVEL_OFFSET/4) &= ~(1 << 4);
    *(gpio + GPIO_INT_POLARITY_OFFSET/4) &= ~(1 << 4);
    *(gpio + GPIO_INTEN_OFFSET/4) |= (1 << 4);
}

void handle_interrupt(int sig) {
    static int led_index = 0;

    if (*(gpio + GPIO_INT_STATUS_OFFSET/4) & (1 << 4)) {
        // Button interrupt
        for (int i = 0; i < LED_COUNT; i++) {
            *gpio |= (1 << (16 + i));
            usleep(LED_DELAY);
            *gpio &= ~(1 << (16 + i));
        }
        led_index = (led_index + 1) % LED_COUNT;
        *gpio |= (1 << (16 + led_index));
        *(gpio + GPIO_INT_STATUS_OFFSET/4) |= (1 << 4); // clear interrupt status
    }
}

int main() {
    signal(SIGIO, handle_interrupt);
    setup_gpio();

    while (1) {
        pause();
    }

    return 0;
}

这个程序使用了龙芯系统的GPIO模块来控制8个LED灯，同时监听一个按键的中断信号。每次按下按键，流水灯会依次亮起，然后再从头开始循环。