1 /* Round __float128 to integer away from zero.
2 Copyright (C) 1997, 1999 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
5 Jakub Jelinek <jj@ultra.linux.cz>, 1999.
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
16
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, write to the Free
19 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
20 02111-1307 USA. */
21
22 #include "quadmath-imp.h"
23
24 static const __float128 huge = 1.0E4930Q;
25
26
27 __float128
roundq(__float128 x)28 roundq (__float128 x)
29 {
30 int32_t j0;
31 uint64_t i1, i0;
32
33 GET_FLT128_WORDS64 (i0, i1, x);
34 j0 = ((i0 >> 48) & 0x7fff) - 0x3fff;
35 if (j0 < 31)
36 {
37 if (j0 < 0)
38 {
39 if (huge + x > 0.0)
40 {
41 i0 &= 0x8000000000000000ULL;
42 if (j0 == -1)
43 i0 |= 0x3fff000000000000LL;
44 i1 = 0;
45 }
46 }
47 else
48 {
49 uint64_t i = 0x0000ffffffffffffLL >> j0;
50 if (((i0 & i) | i1) == 0)
51 /* X is integral. */
52 return x;
53 if (huge + x > 0.0)
54 {
55 /* Raise inexact if x != 0. */
56 i0 += 0x0000800000000000LL >> j0;
57 i0 &= ~i;
58 i1 = 0;
59 }
60 }
61 }
62 else if (j0 > 111)
63 {
64 if (j0 == 0x4000)
65 /* Inf or NaN. */
66 return x + x;
67 else
68 return x;
69 }
70 else
71 {
72 uint64_t i = -1ULL >> (j0 - 48);
73 if ((i1 & i) == 0)
74 /* X is integral. */
75 return x;
76
77 if (huge + x > 0.0)
78 {
79 /* Raise inexact if x != 0. */
80 uint64_t j = i1 + (1LL << (111 - j0));
81 if (j < i1)
82 i0 += 1;
83 i1 = j;
84 }
85 i1 &= ~i;
86 }
87
88 SET_FLT128_WORDS64 (x, i0, i1);
89 return x;
90 }
91