#include <stdio.h>
#include <fcntl.h>
#include <signal.h>

#define DEFLPTADR 0x378
#define DEFLPDEV "/dev/lp0"

int LPTport = DEFLPTADR;
char LPdev[20] = DEFLPDEV;
int fd;

__inline__ static void outp(unsigned short port,char value)
{  __asm__ volatile ("outb %0,%1"
            ::"a" ((char) value), "d"((unsigned short) port));
}

void prepare (void)
{
	fd=open(LPdev,O_RDWR | O_NONBLOCK);
	if (fd < 0)
	{
		perror ("lpdiff open");
		exit (10);
	}
	if (ioperm(LPTport,3,1))
	{
		perror ("lpt ioperm");
		exit (1);
	}
}

void finish (void)
{
	close(fd);
	if (ioperm(LPTport,3,0))
	{
		perror("lpt ioperm");
		exit (1);
	}
}

#define sleepy 3000

int main(int argc, char *argv[])
{
  int i;
  if (argc > 1) {
    char *p;
    int secs = strtol(argv[1], &p, 0);
    printf("setting alarm clock to %d seconds from now...\n", secs);

    setvbuf (stdout,NULL,_IONBF,0); /* turn off buffering */
    prepare();

/*
13:
000000000000000000008401
123456789012345678901234
*/
    for (i=0; i<24; i++) {
      if ( secs & (1 << (23-i)))
        outp (LPTport,5);
      else
        outp (LPTport,1);
      usleep(sleepy);
      outp (LPTport,0);
      usleep(sleepy);
    }

       finish();

  } else {
    printf ("Error. Usage: wake <seconds>\n");
  }


  return 0;
}