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#include <math-use-builtins.h>
27
28double
29__rint (double x)
30{
31#if USE_RINT_BUILTIN
32 return __builtin_rint (x);
33#else
34 /* Use generic implementation. */
35 static const double
36 TWO52[2] = {
37 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
38 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
39 };
40 int64_t i0, sx;
41 int32_t j0;
42 EXTRACT_WORDS64 (i0, x);
43 sx = (i0 >> 63) & 1;
44 j0 = ((i0 >> 52) & 0x7ff) - 0x3ff;
45 if (j0 < 52)
46 {
47 if (j0 < 0)
48 {
49 double w = TWO52[sx] + x;
50 double t = w - TWO52[sx];
51 EXTRACT_WORDS64 (i0, t);
52 INSERT_WORDS64 (t, (i0 & UINT64_C (0x7fffffffffffffff))
53 | (sx << 63));
54 return t;
55 }
56 }
57 else
58 {
59 if (j0 == 0x400)
60 return x + x; /* inf or NaN */
61 else
62 return x; /* x is integral */
63 }
64 double w = TWO52[sx] + x;
65 return w - TWO52[sx];
66#endif /* ! USE_RINT_BUILTIN */
67}
68#ifndef __rint
69libm_alias_double (__rint, rint)
70#endif
71