| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame] | 1 | /* Copyright (C) 2005-2016 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 | __divtc3 (long double a, long double b, long double c, long double d) |
| 26 | { |
| 27 | long double denom, ratio, x, y; |
| 28 | |
| 29 | /* ??? We can get better behavior from logarithmic scaling instead of |
| 30 | the division. But that would mean starting to link libgcc against |
| 31 | libm. We could implement something akin to ldexp/frexp as gcc builtins |
| 32 | fairly easily... */ |
| 33 | if (fabsl (c) < fabsl (d)) |
| 34 | { |
| 35 | ratio = c / d; |
| 36 | denom = (c * ratio) + d; |
| 37 | x = ((a * ratio) + b) / denom; |
| 38 | y = ((b * ratio) - a) / denom; |
| 39 | } |
| 40 | else |
| 41 | { |
| 42 | ratio = d / c; |
| 43 | denom = (d * ratio) + c; |
| 44 | x = ((b * ratio) + a) / denom; |
| 45 | y = (b - (a * ratio)) / denom; |
| 46 | } |
| 47 | |
| 48 | /* Recover infinities and zeros that computed as NaN+iNaN; the only cases |
| 49 | are nonzero/zero, infinite/finite, and finite/infinite. */ |
| 50 | if (isnan (x) && isnan (y)) |
| 51 | { |
| 52 | if (denom == 0.0 && (!isnan (a) || !isnan (b))) |
| 53 | { |
| 54 | x = __copysignl (INFINITY, c) * a; |
| 55 | y = __copysignl (INFINITY, c) * b; |
| 56 | } |
| 57 | else if ((isinf (a) || isinf (b)) |
| 58 | && isfinite (c) && isfinite (d)) |
| 59 | { |
| 60 | a = __copysignl (isinf (a) ? 1 : 0, a); |
| 61 | b = __copysignl (isinf (b) ? 1 : 0, b); |
| 62 | x = INFINITY * (a * c + b * d); |
| 63 | y = INFINITY * (b * c - a * d); |
| 64 | } |
| 65 | else if ((isinf (c) || isinf (d)) |
| 66 | && isfinite (a) && isfinite (b)) |
| 67 | { |
| 68 | c = __copysignl (isinf (c) ? 1 : 0, c); |
| 69 | d = __copysignl (isinf (d) ? 1 : 0, d); |
| 70 | x = 0.0 * (a * c + b * d); |
| 71 | y = 0.0 * (b * c - a * d); |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | return x + I * y; |
| 76 | } |