#include <stdio.h>
#include <unistd.h>

static unsigned cyc_hi = 0;
static unsigned cyc_lo = 0;

void access_counter(unsigned *hi, unsigned *lo)
{
  asm("rdtsc; movl %%edx,%0; movl %%eax,%1"
      : "=r" (*hi), "=r" (*lo)
      :
      : "%edx", "%eax");
}

int main(int argc, char ** argv)
{
  access_counter(&cyc_hi, &cyc_lo);
  printf("counter = %8.8x.%8.8x\n", cyc_hi, cyc_lo);
  sleep(1);
  access_counter(&cyc_hi, &cyc_lo);
  printf("counter = %8.8x.%8.8x\n", cyc_hi, cyc_lo);
  return 0;
}