#define _ISOC99_SOURCE

#include <stdio.h>
#include <math.h>
#include <time.h>

#include <sys/time.h>

#define ITER 250000

double fp(double frac, int divs)
{
	double i;
	double n;

	i = log2(divs) + 1;
	n = frac;

	while (i && n > floor(n)) {
		i--;
		n *= 2.0;
	}
	
	return i;
}

double mod(double frac, int divs)
{
	int x, n;
	
	x = frac * divs;
	
	for (n = divs; n > 0; n >>= 1) {
		if ((x % n) == 0)
			return log2((double)n) + 1.0;
	}

	return 0.0;
}

int integer(double frac, int divs)
{
	int i, m, n;
	
	i = log2(divs) + 1;
	m = (1 << (i - 1)) - 1;
	n = frac * divs;

	while (i && (n & m)) {
		i--;
		m >>= 1;
	}
	
	return i;
}

long utime_sub(struct timeval first, struct timeval last)
{
	return ((last.tv_sec - first.tv_sec) * 1000000) + (last.tv_usec - first.tv_usec);
}

int main(int argc, char *argv[])
{
	struct timeval start, end;
	int x, y;
	
	for (x = 0; x < 16; x++) {
		printf("%.0f ", fp((double)x / 16.0, 16));
	}
	printf("\n");

	for (x = 0; x < 16; x++) {
		printf("%.0f ", mod((double)x / 16.0, 16));
	}
	printf("\n");

	for (x = 0; x < 16; x++) {
		printf("%d ", integer((double)x / 16.0, 16));
	}
	printf("\n");

	gettimeofday(&start, NULL);
	for (y = 0; y < ITER; y++) {
		for (x = 0; x < 16; x++)
			fp((double)x / 8.0, 8);
	}
	gettimeofday(&end, NULL);
	printf("fp : %ld us\n", utime_sub(start, end));

	gettimeofday(&start, NULL);
	for (y = 0; y < ITER; y++) {
		for (x = 0; x < 16; x++)
			mod((double)x / 8.0, 8);
	}
	gettimeofday(&end, NULL);
	printf("mod: %ld us\n", utime_sub(start, end));

	gettimeofday(&start, NULL);
	for (y = 0; y < ITER; y++) {
		for (x = 0; x < 16; x++)
			integer((double)x / 8.0, 8);
	}
	gettimeofday(&end, NULL);
	printf("int: %ld us\n", utime_sub(start, end));

	return 0;
}