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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 float zero = 0.0; | |
26 | ||
27 | ||
28 | float | |
29 | __remquof (float x, float y, int *quo) | |
30 | { | |
34b402e5 | 31 | int32_t hx,hy; |
bc9f6000 | 32 | u_int32_t sx; |
34b402e5 | 33 | int cquo, qs; |
bc9f6000 UD |
34 | |
35 | GET_FLOAT_WORD (hx, x); | |
34b402e5 | 36 | GET_FLOAT_WORD (hy, 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 UD |
43 | if (hy == 0) |
44 | return (x * y) / (x * y); /* y = 0 */ | |
bc9f6000 | 45 | if ((hx >= 0x7f800000) /* x not finite */ |
34b402e5 UD |
46 | || (hy > 0x7f800000)) /* y is NaN */ |
47 | return (x * y) / (x * y); | |
bc9f6000 | 48 | |
34b402e5 | 49 | if (hy <= 0x7dffffff) |
63551311 | 50 | x = __ieee754_fmodf (x, 8 * y); /* now x < 8y */ |
bc9f6000 | 51 | |
34b402e5 | 52 | if ((hx - hy) == 0) |
bc9f6000 UD |
53 | { |
54 | *quo = qs ? -1 : 1; | |
55 | return zero * x; | |
56 | } | |
57 | ||
58 | x = fabsf (x); | |
34b402e5 | 59 | y = fabsf (y); |
bc9f6000 UD |
60 | cquo = 0; |
61 | ||
63551311 | 62 | if (x >= 4 * y) |
bc9f6000 | 63 | { |
34b402e5 | 64 | x -= 4 * y; |
63551311 UD |
65 | cquo += 4; |
66 | } | |
67 | if (x >= 2 * y) | |
68 | { | |
69 | x -= 2 * y; | |
bc9f6000 UD |
70 | cquo += 2; |
71 | } | |
bc9f6000 | 72 | |
34b402e5 | 73 | if (hy < 0x01000000) |
bc9f6000 | 74 | { |
34b402e5 | 75 | if (x + x > y) |
bc9f6000 | 76 | { |
34b402e5 | 77 | x -= y; |
d705269e | 78 | ++cquo; |
34b402e5 | 79 | if (x + x >= y) |
63551311 UD |
80 | { |
81 | x -= y; | |
82 | ++cquo; | |
83 | } | |
bc9f6000 UD |
84 | } |
85 | } | |
86 | else | |
87 | { | |
34b402e5 | 88 | float y_half = 0.5 * y; |
63551311 | 89 | if (x > y_half) |
bc9f6000 | 90 | { |
34b402e5 | 91 | x -= y; |
d705269e | 92 | ++cquo; |
34b402e5 | 93 | if (x >= y_half) |
63551311 UD |
94 | { |
95 | x -= y; | |
96 | ++cquo; | |
97 | } | |
bc9f6000 UD |
98 | } |
99 | } | |
100 | ||
101 | *quo = qs ? -cquo : cquo; | |
102 | ||
63551311 UD |
103 | if (sx) |
104 | x = -x; | |
bc9f6000 UD |
105 | return x; |
106 | } | |
107 | weak_alias (__remquof, remquof) |