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


int main(int argc, char **argv)
{
	int fd = open("/dev/mem", O_RDWR);
	void *base;

	if (fd < 0) {
		fputs("Unable to open /dev/mem\n", stderr);
		return -1;
	}
	base = mmap(NULL, 4096 ,PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0xfed00000);
	if ((long)base == -1) {
		fputs("Unable to mmap HPET\n", stderr);
		return -1;
	}
	*(unsigned long *) (base+0xf0) = 0;
	return 0;
}