| /* Copyright (C) 2005, 2006 Free Software Foundation, Inc. |

| This file is part of the GNU C Library. |

| Contributed by Richard Henderson <rth@redhat.com>, 2005. |

| |

| The GNU C Library is free software; you can redistribute it and/or |

| modify it under the terms of the GNU Lesser General Public |

| License as published by the Free Software Foundation; either |

| version 2.1 of the License, or (at your option) any later version. |

| |

| The GNU C Library is distributed in the hope that it will be useful, |

| but WITHOUT ANY WARRANTY; without even the implied warranty of |

| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |

| Lesser General Public License for more details. |

| |

| You should have received a copy of the GNU Lesser General Public |

| License along with the GNU C Library; if not, write to the Free |

| Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |

| 02111-1307 USA. */ |

| |

| #include <stdbool.h> |

| #include <math.h> |

| #include <complex.h> |

| |

| attribute_hidden |

| long double _Complex |

| __divtc3 (long double a, long double b, long double c, long double d) |

| { |

| long double denom, ratio, x, y; |

| |

| /* ??? We can get better behavior from logarithmic scaling instead of |

| the division. But that would mean starting to link libgcc against |

| libm. We could implement something akin to ldexp/frexp as gcc builtins |

| fairly easily... */ |

| if (fabsl (c) < fabsl (d)) |

| { |

| ratio = c / d; |

| denom = (c * ratio) + d; |

| x = ((a * ratio) + b) / denom; |

| y = ((b * ratio) - a) / denom; |

| } |

| else |

| { |

| ratio = d / c; |

| denom = (d * ratio) + c; |

| x = ((b * ratio) + a) / denom; |

| y = (b - (a * ratio)) / denom; |

| } |

| |

| /* Recover infinities and zeros that computed as NaN+iNaN; the only cases |

| are nonzero/zero, infinite/finite, and finite/infinite. */ |

| if (isnan (x) && isnan (y)) |

| { |

| if (denom == 0.0 && (!isnan (a) || !isnan (b))) |

| { |

| x = __copysignl (INFINITY, c) * a; |

| y = __copysignl (INFINITY, c) * b; |

| } |

| else if ((isinf (a) || isinf (b)) && isfinite (c) && isfinite (d)) |

| { |

| a = __copysignl (isinf (a) ? 1 : 0, a); |

| b = __copysignl (isinf (b) ? 1 : 0, b); |

| x = INFINITY * (a * c + b * d); |

| y = INFINITY * (b * c - a * d); |

| } |

| else if ((isinf (c) || isinf (d)) && isfinite (a) && isfinite (b)) |

| { |

| c = __copysignl (isinf (c) ? 1 : 0, c); |

| d = __copysignl (isinf (d) ? 1 : 0, d); |

| x = 0.0 * (a * c + b * d); |

| y = 0.0 * (b * c - a * d); |

| } |

| } |

| |

| return x + I * y; |

| } |