1#include <float.h>
 2#include <math.h>
 3#include <stdint.h>
 4
 5#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1
 6#define EPS DBL_EPSILON
 7#elif FLT_EVAL_METHOD==2
 8#define EPS LDBL_EPSILON
 9#endif
10static const double_t toint = 1/EPS;
11
12double rint(double x)
13{
14	union {double f; uint64_t i;} u = {x};
15	int e = u.i>>52 & 0x7ff;
16	int s = u.i>>63;
17	double_t y;
18
19	if (e >= 0x3ff+52)
20		return x;
21	if (s)
22		y = x - toint + toint;
23	else
24		y = x + toint - toint;
25	if (y == 0)
26		return s ? -0.0 : 0;
27	return y;
28}