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
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
/* @(#)s_rint.c 5.1 93/09/24 */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
/*
* rint(x)
* Return x rounded to integral value according to the prevailing
* rounding mode.
* Method:
* Using floating addition.
* Exception:
* Inexact flag raised if x not equal to rint(x).
*/
#include <math.h>
#include <math_private.h>
static const double
TWO52[2]={
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
};
double
__rint(double x)
{
int32_t i0,j0,sx;
double w,t;
GET_HIGH_WORD(i0,x);
sx = (i0>>31)&1;
j0 = ((i0>>20)&0x7ff)-0x3ff;
if(j0<52) {
if(j0<0) {
w = TWO52[sx]+x;
t = w-TWO52[sx];
GET_HIGH_WORD(i0,t);
SET_HIGH_WORD(t,(i0&0x7fffffff)|(sx<<31));
return t;
}
} else {
if(j0==0x400) return x+x; /* inf or NaN */
else return x; /* x is integral */
}
w = TWO52[sx]+x;
return w-TWO52[sx];
}
#ifndef __rint
weak_alias (__rint, rint)
# ifdef NO_LONG_DOUBLE
strong_alias (__rint, __rintl)
weak_alias (__rint, rintl)
# endif
#endif
|
