/* $Id: ioploop.c,v 1.1 2009/02/28 15:01:23 kostik Exp kostik $ */

#include <sys/time.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <time.h>

static const unsigned int port_num = 0x130;

unsigned char
inb(unsigned int port)
{
	unsigned char data;

	__asm __volatile("inb %%dx,%0" : "=a" (data) : "d" (port));
	return (data);
}

void
sigalarm_handler(int signo)
{

	inb(port_num);
}

int
main(int argc, char *argv[])
{
	struct sigaction sa;
	struct timespec rqtp;
	struct itimerval it;
	int io_fd;
	int i;

	memset(&rqtp, 0, sizeof(rqtp));
	rqtp.tv_sec = 0;
	rqtp.tv_nsec = 100000000;
	i = 0;

	memset(&sa, 0, sizeof(sa));
	sa.sa_handler = sigalarm_handler;
	if (sigaction(SIGALRM, &sa, NULL) == -1) {
		fprintf(stderr, "sigaction(SIGALRM): %s\n", strerror(errno));
		return (1);
	}

	memset(&it, 0, sizeof(it));
	it.it_interval.tv_sec = 0;
	it.it_interval.tv_usec = 333333;
	it.it_value = it.it_interval;
	if (setitimer(ITIMER_REAL, &it, NULL) == -1) {
		fprintf(stderr, "setitimer: %s\n", strerror(errno));
		return (1);
	}

	io_fd = open("/dev/io", O_RDWR);
	if (io_fd == -1) {
		fprintf(stderr, "Opening /dev/io: %s\n", strerror(errno));
		return (1);
	}

	for (;;) {
		inb(port_num + i);
		if (++i == 10)
			i = 0;
		nanosleep(&rqtp, NULL);
	}
	
	return (0);
}