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581c785b | 1 | /* Copyright (C) 2005-2022 Free Software Foundation, Inc. |
fea3f995 | 2 | This file is part of the GNU C Library. |
fea3f995 RM |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
fea3f995 RM |
17 | |
18 | #include <stdbool.h> | |
19 | #include <math.h> | |
20 | #include <complex.h> | |
21 | ||
22 | attribute_hidden | |
23 | long double _Complex | |
24 | __multc3 (long double a, long double b, long double c, long double d) | |
25 | { | |
26 | long double ac, bd, ad, bc, x, y; | |
27 | ||
28 | ac = a * c; | |
29 | bd = b * d; | |
30 | ad = a * d; | |
31 | bc = b * c; | |
32 | ||
33 | x = ac - bd; | |
34 | y = ad + bc; | |
35 | ||
36 | if (isnan (x) && isnan (y)) | |
37 | { | |
38 | /* Recover infinities that computed as NaN + iNaN. */ | |
39 | bool recalc = 0; | |
fe8c2b33 | 40 | if (isinf (a) || isinf (b)) |
fea3f995 RM |
41 | { |
42 | /* z is infinite. "Box" the infinity and change NaNs in | |
43 | the other factor to 0. */ | |
81dca813 JM |
44 | a = copysignl (isinf (a) ? 1 : 0, a); |
45 | b = copysignl (isinf (b) ? 1 : 0, b); | |
46 | if (isnan (c)) c = copysignl (0, c); | |
47 | if (isnan (d)) d = copysignl (0, d); | |
fea3f995 RM |
48 | recalc = 1; |
49 | } | |
fe8c2b33 | 50 | if (isinf (c) || isinf (d)) |
fea3f995 RM |
51 | { |
52 | /* w is infinite. "Box" the infinity and change NaNs in | |
53 | the other factor to 0. */ | |
81dca813 JM |
54 | c = copysignl (isinf (c) ? 1 : 0, c); |
55 | d = copysignl (isinf (d) ? 1 : 0, d); | |
56 | if (isnan (a)) a = copysignl (0, a); | |
57 | if (isnan (b)) b = copysignl (0, b); | |
fea3f995 RM |
58 | recalc = 1; |
59 | } | |
60 | if (!recalc | |
fe8c2b33 WD |
61 | && (isinf (ac) || isinf (bd) |
62 | || isinf (ad) || isinf (bc))) | |
fea3f995 RM |
63 | { |
64 | /* Recover infinities from overflow by changing NaNs to 0. */ | |
81dca813 JM |
65 | if (isnan (a)) a = copysignl (0, a); |
66 | if (isnan (b)) b = copysignl (0, b); | |
67 | if (isnan (c)) c = copysignl (0, c); | |
68 | if (isnan (d)) d = copysignl (0, d); | |
fea3f995 RM |
69 | recalc = 1; |
70 | } | |
71 | if (recalc) | |
72 | { | |
73 | x = INFINITY * (a * c - b * d); | |
74 | y = INFINITY * (a * d + b * c); | |
75 | } | |
76 | } | |
77 | ||
78 | return x + I * y; | |
79 | } |