#include <sys/time.h>
#include <time.h>
#include <stdio.h>
#include <errno.h>

static inline unsigned long rdtsc ()
{
  unsigned long var;
  unsigned int hi, lo;

  asm volatile ("rdtsc" : "=a" (lo), "=d" (hi));
  var = ((unsigned long long int) hi << 32) | lo;

  return var;
}

typedef unsigned long long u64;

int main()
{
	struct timespec ts;
	u64 start, end, delta, mid;
	do {
		start= rdtsc();
		clock_gettime(CLOCK_MONOTONIC_RAW, &ts);
		end = rdtsc();
		delta = end-start;
	} while (delta  > 20000);   // make sure the reads were not preempted
	mid = start + (delta +(delta/2))/2; //round-closest
	printf("%llu %llu %llu\n", start, end, delta);
	printf("MONO_RAW: %llu TSC: %llu\n", (u64)ts.tv_sec * 1000000000 + ts.tv_nsec, mid);
}