1/*
2 * ====================================================
3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4 *
5 * Developed at SunPro, a Sun Microsystems, Inc. business.
6 * Permission to use, copy, modify, and distribute this
7 * software is freely granted, provided that this notice
8 * is preserved.
9 * ====================================================
10 */
11
12/*
13 * rint(x)
14 * Return x rounded to integral value according to the prevailing
15 * rounding mode.
16 * Method:
17 * Using floating addition.
18 * Exception:
19 * Inexact flag raised if x not equal to rint(x).
20 */
21
22#define NO_MATH_REDIRECT
23#include <math.h>
24#include <math_private.h>
25#include <libm-alias-double.h>
26
27static const double
28TWO52[2]={
29 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
30 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
31};
32
33double
34__rint(double x)
35{
36 int64_t i0,sx;
37 int32_t j0;
38 EXTRACT_WORDS64(i0,x);
39 sx = (i0>>63)&1;
40 j0 = ((i0>>52)&0x7ff)-0x3ff;
41 if(j0<52) {
42 if(j0<0) {
43 double w = TWO52[sx]+x;
44 double t = w-TWO52[sx];
45 EXTRACT_WORDS64(i0,t);
46 INSERT_WORDS64(t,(i0&UINT64_C(0x7fffffffffffffff))|(sx<<63));
47 return t;
48 }
49 } else {
50 if(j0==0x400) return x+x; /* inf or NaN */
51 else return x; /* x is integral */
52 }
53 double w = TWO52[sx]+x;
54 return w-TWO52[sx];
55}
56#ifndef __rint
57libm_alias_double (__rint, rint)
58#endif
59