| /* Complex square root of long double value. |
| Copyright (C) 1997-2014 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>. |
| Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. |
| |
| 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <complex.h> |
| #include <math.h> |
| #include <math_private.h> |
| #include <float.h> |
| |
| __complex__ long double |
| __csqrtl (__complex__ long double x) |
| { |
| __complex__ long double res; |
| int rcls = fpclassify (__real__ x); |
| int icls = fpclassify (__imag__ x); |
| |
| if (__builtin_expect (rcls <= FP_INFINITE || icls <= FP_INFINITE, 0)) |
| { |
| if (icls == FP_INFINITE) |
| { |
| __real__ res = HUGE_VALL; |
| __imag__ res = __imag__ x; |
| } |
| else if (rcls == FP_INFINITE) |
| { |
| if (__real__ x < 0.0) |
| { |
| __real__ res = icls == FP_NAN ? __nanl ("") : 0; |
| __imag__ res = __copysignl (HUGE_VALL, __imag__ x); |
| } |
| else |
| { |
| __real__ res = __real__ x; |
| __imag__ res = (icls == FP_NAN |
| ? __nanl ("") : __copysignl (0.0, __imag__ x)); |
| } |
| } |
| else |
| { |
| __real__ res = __nanl (""); |
| __imag__ res = __nanl (""); |
| } |
| } |
| else |
| { |
| if (__builtin_expect (icls == FP_ZERO, 0)) |
| { |
| if (__real__ x < 0.0) |
| { |
| __real__ res = 0.0; |
| __imag__ res = __copysignl (__ieee754_sqrtl (-__real__ x), |
| __imag__ x); |
| } |
| else |
| { |
| __real__ res = fabsl (__ieee754_sqrtl (__real__ x)); |
| __imag__ res = __copysignl (0.0, __imag__ x); |
| } |
| } |
| else if (__builtin_expect (rcls == FP_ZERO, 0)) |
| { |
| long double r; |
| if (fabsl (__imag__ x) >= 2.0L * LDBL_MIN) |
| r = __ieee754_sqrtl (0.5L * fabsl (__imag__ x)); |
| else |
| r = 0.5L * __ieee754_sqrtl (2.0L * fabsl (__imag__ x)); |
| |
| __real__ res = r; |
| __imag__ res = __copysignl (r, __imag__ x); |
| } |
| else |
| { |
| long double d, r, s; |
| int scale = 0; |
| |
| if (fabsl (__real__ x) > LDBL_MAX / 4.0L) |
| { |
| scale = 1; |
| __real__ x = __scalbnl (__real__ x, -2 * scale); |
| __imag__ x = __scalbnl (__imag__ x, -2 * scale); |
| } |
| else if (fabsl (__imag__ x) > LDBL_MAX / 4.0L) |
| { |
| scale = 1; |
| if (fabsl (__real__ x) >= 4.0L * LDBL_MIN) |
| __real__ x = __scalbnl (__real__ x, -2 * scale); |
| else |
| __real__ x = 0.0L; |
| __imag__ x = __scalbnl (__imag__ x, -2 * scale); |
| } |
| else if (fabsl (__real__ x) < LDBL_MIN |
| && fabsl (__imag__ x) < LDBL_MIN) |
| { |
| scale = -(LDBL_MANT_DIG / 2); |
| __real__ x = __scalbnl (__real__ x, -2 * scale); |
| __imag__ x = __scalbnl (__imag__ x, -2 * scale); |
| } |
| |
| d = __ieee754_hypotl (__real__ x, __imag__ x); |
| /* Use the identity 2 Re res Im res = Im x |
| to avoid cancellation error in d +/- Re x. */ |
| if (__real__ x > 0) |
| { |
| r = __ieee754_sqrtl (0.5L * (d + __real__ x)); |
| s = 0.5L * (__imag__ x / r); |
| } |
| else |
| { |
| s = __ieee754_sqrtl (0.5L * (d - __real__ x)); |
| r = fabsl (0.5L * (__imag__ x / s)); |
| } |
| |
| if (scale) |
| { |
| r = __scalbnl (r, scale); |
| s = __scalbnl (s, scale); |
| } |
| |
| __real__ res = r; |
| __imag__ res = __copysignl (s, __imag__ x); |
| } |
| } |
| |
| return res; |
| } |
| weak_alias (__csqrtl, csqrtl) |
