ref: 35e2b5b8391c23f01d41a181bc9d6d9dddd5425f
dir: /libnpe/log2.c/
#include <math.h>
#include "_npe.h"
double
log2(double x)
{
	if(x == 0)
		return -hugeD;
	if(x < 0 || isNaN(x))
		return NaN();
	return log(x)*ln2o1;
}
float
log2f(float x)
{
	if(x == 0)
		return -hugeF;
	return log2(x);
}