| lh | 9ed821d | 2023-04-07 01:36:19 -0700 | [diff] [blame] | 1 | /* Copyright (C) 2005-2015 Free Software Foundation, Inc. |
| 2 | This file is part of the GNU C Library. |
| 3 | Contributed by Richard Henderson <rth@redhat.com>, 2005. |
| 4 | |
| 5 | The GNU C Library is free software; you can redistribute it and/or |
| 6 | modify it under the terms of the GNU Lesser General Public |
| 7 | License as published by the Free Software Foundation; either |
| 8 | version 2.1 of the License, or (at your option) any later version. |
| 9 | |
| 10 | The GNU C Library is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | Lesser General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU Lesser General Public |
| 16 | License along with the GNU C Library; if not, see |
| 17 | <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include <stdbool.h> |
| 20 | #include <math.h> |
| 21 | #include <complex.h> |
| 22 | |
| 23 | attribute_hidden |
| 24 | long double _Complex |
| 25 | __multc3 (long double a, long double b, long double c, long double d) |
| 26 | { |
| 27 | long double ac, bd, ad, bc, x, y; |
| 28 | |
| 29 | ac = a * c; |
| 30 | bd = b * d; |
| 31 | ad = a * d; |
| 32 | bc = b * c; |
| 33 | |
| 34 | x = ac - bd; |
| 35 | y = ad + bc; |
| 36 | |
| 37 | if (isnan (x) && isnan (y)) |
| 38 | { |
| 39 | /* Recover infinities that computed as NaN + iNaN. */ |
| 40 | bool recalc = 0; |
| 41 | if (__isinf_nsl (a) || __isinf_nsl (b)) |
| 42 | { |
| 43 | /* z is infinite. "Box" the infinity and change NaNs in |
| 44 | the other factor to 0. */ |
| 45 | a = __copysignl (__isinf_nsl (a) ? 1 : 0, a); |
| 46 | b = __copysignl (__isinf_nsl (b) ? 1 : 0, b); |
| 47 | if (isnan (c)) c = __copysignl (0, c); |
| 48 | if (isnan (d)) d = __copysignl (0, d); |
| 49 | recalc = 1; |
| 50 | } |
| 51 | if (__isinf_nsl (c) || __isinf_nsl (d)) |
| 52 | { |
| 53 | /* w is infinite. "Box" the infinity and change NaNs in |
| 54 | the other factor to 0. */ |
| 55 | c = __copysignl (__isinf_nsl (c) ? 1 : 0, c); |
| 56 | d = __copysignl (__isinf_nsl (d) ? 1 : 0, d); |
| 57 | if (isnan (a)) a = __copysignl (0, a); |
| 58 | if (isnan (b)) b = __copysignl (0, b); |
| 59 | recalc = 1; |
| 60 | } |
| 61 | if (!recalc |
| 62 | && (__isinf_nsl (ac) || __isinf_nsl (bd) |
| 63 | || __isinf_nsl (ad) || __isinf_nsl (bc))) |
| 64 | { |
| 65 | /* Recover infinities from overflow by changing NaNs to 0. */ |
| 66 | if (isnan (a)) a = __copysignl (0, a); |
| 67 | if (isnan (b)) b = __copysignl (0, b); |
| 68 | if (isnan (c)) c = __copysignl (0, c); |
| 69 | if (isnan (d)) d = __copysignl (0, d); |
| 70 | recalc = 1; |
| 71 | } |
| 72 | if (recalc) |
| 73 | { |
| 74 | x = INFINITY * (a * c - b * d); |
| 75 | y = INFINITY * (a * d + b * c); |
| 76 | } |
| 77 | } |
| 78 | |
| 79 | return x + I * y; |
| 80 | } |