blob: 3df4c83bb0d948d816563706f4723ef5c8f96e20 (
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
34
35
36
37
38
39
40
41
42
43
|
#include "libm.h" // for FORCE_EVAL
#include <float.h> // for FLT_EPSILON, FLT_EVAL_METHOD
#include <math.h> // for float_t, roundf
#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 roundf(float x)
{
union {
float f;
uint32_t i;
} u = { x };
int e = u.i >> 23 & 0xff;
float_t y;
if (e >= 0x7f + 23)
return x;
if (u.i >> 31)
x = -x;
if (e < 0x7f - 1) {
FORCE_EVAL(x + toint);
return 0 * u.f;
}
y = x + toint - toint - x;
if (y > 0.5f)
y = y + x - 1;
else if (y <= -0.5f)
y = y + x + 1;
else
y = y + x;
if (u.i >> 31)
y = -y;
return y;
}
|
