summaryrefslogtreecommitdiff
path: root/lib/libm/rintf.c
blob: 6de51a6ecbd102c65ca40cd1f9c5bfa55430386c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
#include <float.h>  // for FLT_EPSILON, FLT_EVAL_METHOD
#include <math.h>   // for float_t, rintf
#include <stdint.h> // for uint32_t

#if FLT_EVAL_METHOD == 0
#define EPS FLT_EPSILON
#elif FLT_EVAL_METHOD == 1
#define EPS DBL_EPSILON
#elif FLT_EVAL_METHOD == 2
#define EPS LDBL_EPSILON
#endif
static const float_t toint = 1 / EPS;

float rintf(float x)
{
	union {
		float f;
		uint32_t i;
	} u = { x };
	int e = u.i >> 23 & 0xff;
	int s = u.i >> 31;
	float_t y;

	if (e >= 0x7f + 23)
		return x;
	if (s)
		y = x - toint + toint;
	else
		y = x + toint - toint;
	if (y == 0)
		return s ? -0.0f : 0.0f;
	return y;
}