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dbc9f6c6 | 1 | /* Compute remainder and a congruent to the quotient. |
1a41c323 | 2 | Copyright (C) 1997-2013 Free Software Foundation, Inc. |
dbc9f6c6 JJ |
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 | ||
25 | static const __float128 zero = 0.0; | |
26 | ||
27 | ||
28 | __float128 | |
29 | remquoq (__float128 x, __float128 y, int *quo) | |
30 | { | |
31 | int64_t hx,hy; | |
d6713cb8 | 32 | uint64_t sx,lx,ly,qs; |
dbc9f6c6 JJ |
33 | int cquo; |
34 | ||
35 | GET_FLT128_WORDS64 (hx, lx, x); | |
36 | GET_FLT128_WORDS64 (hy, ly, y); | |
37 | sx = hx & 0x8000000000000000ULL; | |
38 | qs = sx ^ (hy & 0x8000000000000000ULL); | |
39 | hy &= 0x7fffffffffffffffLL; | |
40 | hx &= 0x7fffffffffffffffLL; | |
41 | ||
42 | /* Purge off exception values. */ | |
43 | if ((hy | ly) == 0) | |
44 | return (x * y) / (x * y); /* y = 0 */ | |
45 | if ((hx >= 0x7fff000000000000LL) /* x not finite */ | |
46 | || ((hy >= 0x7fff000000000000LL) /* y is NaN */ | |
47 | && (((hy - 0x7fff000000000000LL) | ly) != 0))) | |
48 | return (x * y) / (x * y); | |
49 | ||
50 | if (hy <= 0x7ffbffffffffffffLL) | |
51 | x = fmodq (x, 8 * y); /* now x < 8y */ | |
52 | ||
53 | if (((hx - hy) | (lx - ly)) == 0) | |
54 | { | |
55 | *quo = qs ? -1 : 1; | |
56 | return zero * x; | |
57 | } | |
58 | ||
59 | x = fabsq (x); | |
60 | y = fabsq (y); | |
61 | cquo = 0; | |
62 | ||
63 | if (x >= 4 * y) | |
64 | { | |
65 | x -= 4 * y; | |
66 | cquo += 4; | |
67 | } | |
68 | if (x >= 2 * y) | |
69 | { | |
70 | x -= 2 * y; | |
71 | cquo += 2; | |
72 | } | |
73 | ||
74 | if (hy < 0x0002000000000000LL) | |
75 | { | |
76 | if (x + x > y) | |
77 | { | |
78 | x -= y; | |
79 | ++cquo; | |
80 | if (x + x >= y) | |
81 | { | |
82 | x -= y; | |
83 | ++cquo; | |
84 | } | |
85 | } | |
86 | } | |
87 | else | |
88 | { | |
89 | __float128 y_half = 0.5Q * y; | |
90 | if (x > y_half) | |
91 | { | |
92 | x -= y; | |
93 | ++cquo; | |
94 | if (x >= y_half) | |
95 | { | |
96 | x -= y; | |
97 | ++cquo; | |
98 | } | |
99 | } | |
100 | } | |
101 | ||
102 | *quo = qs ? -cquo : cquo; | |
103 | ||
104 | if (sx) | |
105 | x = -x; | |
106 | return x; | |
107 | } |