1 files changed, 51 insertions, 0 deletions
diff --git a/math/s_cproj.c b/math/s_cproj.c
new file mode 100644
index 0000000000..8e7ca41df8
--- /dev/null
+++ b/math/s_cproj.c
@@ -0,0 +1,51 @@
+/* Compute projection of complex double value to Riemann sphere.
+   Copyright (C) 1997, 1999 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 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>
+
+
+__complex__ double
+__cproj (__complex__ double x)
+{
+  __complex__ double res;
+
+  if (isnan (__real__ x) && isnan (__imag__ x))
+    return x;
+  else 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