Permalink
Cannot retrieve contributors at this time
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
glibc/math/s_csqrtf.c
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
112 lines (100 sloc)
2.86 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/* Complex square root of float value. | |
Copyright (C) 1997, 1998, 2005 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, write to the Free | |
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
02111-1307 USA. */ | |
#include <complex.h> | |
#include <math.h> | |
#include "math_private.h" | |
__complex__ float | |
__csqrtf (__complex__ float x) | |
{ | |
__complex__ float res; | |
int rcls = fpclassify (__real__ x); | |
int icls = fpclassify (__imag__ x); | |
if (rcls <= FP_INFINITE || icls <= FP_INFINITE) | |
{ | |
if (icls == FP_INFINITE) | |
{ | |
__real__ res = HUGE_VALF; | |
__imag__ res = __imag__ x; | |
} | |
else if (rcls == FP_INFINITE) | |
{ | |
if (__real__ x < 0.0) | |
{ | |
__real__ res = icls == FP_NAN ? __nanf ("") : 0; | |
__imag__ res = __copysignf (HUGE_VALF, __imag__ x); | |
} | |
else | |
{ | |
__real__ res = __real__ x; | |
__imag__ res = (icls == FP_NAN | |
? __nanf ("") : __copysignf (0.0, __imag__ x)); | |
} | |
} | |
else | |
{ | |
__real__ res = __nanf (""); | |
__imag__ res = __nanf (""); | |
} | |
} | |
else | |
{ | |
if (icls == FP_ZERO) | |
{ | |
if (__real__ x < 0.0) | |
{ | |
__real__ res = 0.0; | |
__imag__ res = __copysignf (__ieee754_sqrtf (-__real__ x), | |
__imag__ x); | |
} | |
else | |
{ | |
__real__ res = fabsf (__ieee754_sqrtf (__real__ x)); | |
__imag__ res = __copysignf (0.0, __imag__ x); | |
} | |
} | |
else if (rcls == FP_ZERO) | |
{ | |
float r = __ieee754_sqrtf (0.5 * fabsf (__imag__ x)); | |
__real__ res = r; | |
__imag__ res = __copysignf (r, __imag__ x); | |
} | |
else | |
{ | |
float d, r, s; | |
d = __ieee754_hypotf (__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_sqrtf (0.5f * d + 0.5f * __real__ x); | |
s = (0.5f * __imag__ x) / r; | |
} | |
else | |
{ | |
s = __ieee754_sqrtf (0.5f * d - 0.5f * __real__ x); | |
r = fabsf ((0.5f * __imag__ x) / s); | |
} | |
__real__ res = r; | |
__imag__ res = __copysignf (s, __imag__ x); | |
} | |
} | |
return res; | |
} | |
#ifndef __csqrtf | |
weak_alias (__csqrtf, csqrtf) | |
#endif |