1 |
|
|
/* $OpenBSD: s_lround.c,v 1.8 2016/09/12 19:47:02 guenther Exp $ */ |
2 |
|
|
/* $NetBSD: lround.c,v 1.2 2004/10/13 15:18:32 drochner Exp $ */ |
3 |
|
|
|
4 |
|
|
/*- |
5 |
|
|
* Copyright (c) 2004 |
6 |
|
|
* Matthias Drochner. All rights reserved. |
7 |
|
|
* |
8 |
|
|
* Redistribution and use in source and binary forms, with or without |
9 |
|
|
* modification, are permitted provided that the following conditions |
10 |
|
|
* are met: |
11 |
|
|
* 1. Redistributions of source code must retain the above copyright |
12 |
|
|
* notice, this list of conditions and the following disclaimer. |
13 |
|
|
* 2. Redistributions in binary form must reproduce the above copyright |
14 |
|
|
* notice, this list of conditions and the following disclaimer in the |
15 |
|
|
* documentation and/or other materials provided with the distribution. |
16 |
|
|
* |
17 |
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
18 |
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
19 |
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
20 |
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
21 |
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
22 |
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
23 |
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
24 |
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
25 |
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
26 |
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
27 |
|
|
* SUCH DAMAGE. |
28 |
|
|
*/ |
29 |
|
|
|
30 |
|
|
#include <sys/types.h> |
31 |
|
|
#include <sys/limits.h> |
32 |
|
|
#include <float.h> |
33 |
|
|
#include <math.h> |
34 |
|
|
#include <ieeefp.h> |
35 |
|
|
#include <machine/ieee.h> |
36 |
|
|
#include "math_private.h" |
37 |
|
|
|
38 |
|
|
#ifndef LROUNDNAME |
39 |
|
|
#define LROUNDNAME lround |
40 |
|
|
#define RESTYPE long int |
41 |
|
|
#define RESTYPE_MIN LONG_MIN |
42 |
|
|
#define RESTYPE_MAX LONG_MAX |
43 |
|
|
#endif |
44 |
|
|
|
45 |
|
|
#define RESTYPE_BITS (sizeof(RESTYPE) * 8) |
46 |
|
|
|
47 |
|
|
RESTYPE |
48 |
|
|
LROUNDNAME(double x) |
49 |
|
|
{ |
50 |
|
|
u_int32_t i0, i1; |
51 |
|
|
int e, s, shift; |
52 |
|
|
RESTYPE res; |
53 |
|
|
|
54 |
|
80 |
GET_HIGH_WORD(i0, x); |
55 |
|
40 |
e = i0 >> DBL_FRACHBITS; |
56 |
|
40 |
s = e >> DBL_EXPBITS; |
57 |
|
40 |
e = (e & 0x7ff) - DBL_EXP_BIAS; |
58 |
|
|
|
59 |
|
|
/* 1.0 x 2^-1 is the smallest number which can be rounded to 1 */ |
60 |
✓✓ |
40 |
if (e < -1) |
61 |
|
10 |
return (0); |
62 |
|
|
/* 1.0 x 2^31 (or 2^63) is already too large */ |
63 |
✓✓ |
30 |
if (e >= (int)RESTYPE_BITS - 1) |
64 |
|
5 |
return (s ? RESTYPE_MIN : RESTYPE_MAX); /* ??? unspecified */ |
65 |
|
|
|
66 |
|
|
/* >= 2^52 is already an exact integer */ |
67 |
✓✓ |
25 |
if (e < DBL_FRACBITS) { |
68 |
|
|
/* add 0.5, extraction below will truncate */ |
69 |
|
10 |
x += (s ? -0.5 : 0.5); |
70 |
|
10 |
} |
71 |
|
|
|
72 |
|
25 |
EXTRACT_WORDS(i0, i1, x); |
73 |
|
25 |
e = ((i0 >> DBL_FRACHBITS) & 0x7ff) - DBL_EXP_BIAS; |
74 |
|
25 |
i0 &= 0xfffff; |
75 |
|
25 |
i0 |= (1 << DBL_FRACHBITS); |
76 |
|
|
|
77 |
|
25 |
shift = e - DBL_FRACBITS; |
78 |
✓✓ |
25 |
if (shift >=0) |
79 |
✓✗ |
45 |
res = (shift < RESTYPE_BITS ? (RESTYPE)i1 << shift : 0); |
80 |
|
|
else |
81 |
✓✗ |
30 |
res = (shift > -RESTYPE_BITS ? (RESTYPE)i1 >> -shift : 0); |
82 |
|
25 |
shift += 32; |
83 |
✓✓ |
25 |
if (shift >=0) |
84 |
✓✗ |
45 |
res |= (shift < RESTYPE_BITS ? (RESTYPE)i0 << shift : 0); |
85 |
|
|
else |
86 |
✓✗ |
30 |
res |= (shift > -RESTYPE_BITS ? (RESTYPE)i0 >> -shift : 0); |
87 |
|
|
|
88 |
|
25 |
return (s ? -res : res); |
89 |
|
40 |
} |
90 |
|
|
DEF_STD(LROUNDNAME); |
91 |
|
|
LDBL_MAYBE_UNUSED_CLONE(LROUNDNAME); |