diff options
Diffstat (limited to 'sysdeps/generic/s_cproj.c')
| -rw-r--r-- | sysdeps/generic/s_cproj.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/sysdeps/generic/s_cproj.c b/sysdeps/generic/s_cproj.c new file mode 100644 index 0000000000..fb50bb5a88 --- /dev/null +++ b/sysdeps/generic/s_cproj.c @@ -0,0 +1,49 @@ +/* Compute projection of complex double value to Riemann sphere. + Copyright (C) 1997 Free Software Foundation, Inc. + This file is part of the GNU C Library. + 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. 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> + + +__complex__ double +__cproj (__complex__ double x) +{ + __complex__ double res; + + if (!isfinite (__real__ x) || !isfinite (__imag__ x)) + { + __real__ res = INFINITY; + __imag__ res = __copysign (0.0, __imag__ x); + } + else + { + double den = __real__ x * __real__ x + __imag__ x * __imag__ x + 1.0; + + __real__ res = (2.0 * __real__ x) / den; + __imag__ res = (2.0 * __imag__ x) / den; + } + + return res; +} +weak_alias (__cproj, cproj) +#ifdef NO_LONG_DOUBLE +strong_alias (__cproj, __cprojl) +weak_alias (__cproj, cprojl) +#endif |