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Commit | Line | Data |
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bc9f6000 | 1 | /* Compute remainder and a congruent to the quotient. |
b168057a | 2 | Copyright (C) 1997-2015 Free Software Foundation, Inc. |
bc9f6000 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
41bdb6e2 AJ |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
bc9f6000 UD |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
41bdb6e2 | 14 | Lesser General Public License for more details. |
bc9f6000 | 15 | |
41bdb6e2 | 16 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
bc9f6000 UD |
19 | |
20 | #include <math.h> | |
21 | ||
1ed0291c | 22 | #include <math_private.h> |
bc9f6000 UD |
23 | |
24 | ||
25 | static const double zero = 0.0; | |
26 | ||
27 | ||
28 | double | |
29 | __remquo (double x, double y, int *quo) | |
30 | { | |
c5d5d574 OB |
31 | int32_t hx, hy; |
32 | u_int32_t sx, lx, ly; | |
34b402e5 | 33 | int cquo, qs; |
bc9f6000 UD |
34 | |
35 | EXTRACT_WORDS (hx, lx, x); | |
34b402e5 | 36 | EXTRACT_WORDS (hy, ly, y); |
bc9f6000 | 37 | sx = hx & 0x80000000; |
34b402e5 UD |
38 | qs = sx ^ (hy & 0x80000000); |
39 | hy &= 0x7fffffff; | |
bc9f6000 UD |
40 | hx &= 0x7fffffff; |
41 | ||
42 | /* Purge off exception values. */ | |
34b402e5 | 43 | if ((hy | ly) == 0) |
c5d5d574 OB |
44 | return (x * y) / (x * y); /* y = 0 */ |
45 | if ((hx >= 0x7ff00000) /* x not finite */ | |
46 | || ((hy >= 0x7ff00000) /* p is NaN */ | |
34b402e5 UD |
47 | && (((hy - 0x7ff00000) | ly) != 0))) |
48 | return (x * y) / (x * y); | |
bc9f6000 | 49 | |
34b402e5 | 50 | if (hy <= 0x7fbfffff) |
c5d5d574 | 51 | x = __ieee754_fmod (x, 8 * y); /* now x < 8y */ |
bc9f6000 | 52 | |
34b402e5 | 53 | if (((hx - hy) | (lx - ly)) == 0) |
bc9f6000 UD |
54 | { |
55 | *quo = qs ? -1 : 1; | |
56 | return zero * x; | |
57 | } | |
58 | ||
c5d5d574 OB |
59 | x = fabs (x); |
60 | y = fabs (y); | |
bc9f6000 UD |
61 | cquo = 0; |
62 | ||
63551311 | 63 | if (x >= 4 * y) |
bc9f6000 | 64 | { |
34b402e5 | 65 | x -= 4 * y; |
63551311 UD |
66 | cquo += 4; |
67 | } | |
68 | if (x >= 2 * y) | |
69 | { | |
70 | x -= 2 * y; | |
bc9f6000 UD |
71 | cquo += 2; |
72 | } | |
bc9f6000 | 73 | |
34b402e5 | 74 | if (hy < 0x00200000) |
bc9f6000 | 75 | { |
34b402e5 | 76 | if (x + x > y) |
bc9f6000 | 77 | { |
34b402e5 | 78 | x -= y; |
d705269e | 79 | ++cquo; |
34b402e5 | 80 | if (x + x >= y) |
63551311 UD |
81 | { |
82 | x -= y; | |
83 | ++cquo; | |
84 | } | |
bc9f6000 UD |
85 | } |
86 | } | |
87 | else | |
88 | { | |
34b402e5 | 89 | double y_half = 0.5 * y; |
63551311 | 90 | if (x > y_half) |
bc9f6000 | 91 | { |
34b402e5 | 92 | x -= y; |
d705269e | 93 | ++cquo; |
34b402e5 | 94 | if (x >= y_half) |
63551311 UD |
95 | { |
96 | x -= y; | |
97 | ++cquo; | |
98 | } | |
bc9f6000 UD |
99 | } |
100 | } | |
101 | ||
102 | *quo = qs ? -cquo : cquo; | |
103 | ||
63551311 UD |
104 | if (sx) |
105 | x = -x; | |
bc9f6000 UD |
106 | return x; |
107 | } | |
108 | weak_alias (__remquo, remquo) | |
5649a1d6 UD |
109 | #ifdef NO_LONG_DOUBLE |
110 | strong_alias (__remquo, __remquol) | |
111 | weak_alias (__remquo, remquol) | |
112 | #endif |