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authorJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
committerJakub Jelinek <jakub@redhat.com>2007-07-12 18:26:36 +0000
commit0ecb606cb6cf65de1d9fc8a919bceb4be476c602 (patch)
tree2ea1f8305970753e4a657acb2ccc15ca3eec8e2c /math/s_catanf.c
parent7d58530341304d403a6626d7f7a1913165fe2f32 (diff)
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2.5-18.1
Diffstat (limited to 'math/s_catanf.c')
-rw-r--r--math/s_catanf.c87
1 files changed, 87 insertions, 0 deletions
diff --git a/math/s_catanf.c b/math/s_catanf.c
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+++ b/math/s_catanf.c
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+/* Return arc tangent of complex float value.
+   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 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
+__catanf (__complex__ float x)
+{
+  __complex__ float res;
+  int rcls = fpclassify (__real__ x);
+  int icls = fpclassify (__imag__ x);
+
+  if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
+    {
+      if (rcls == FP_INFINITE)
+	{
+	  __real__ res = __copysignf (M_PI_2, __real__ x);
+	  __imag__ res = __copysignf (0.0, __imag__ x);
+	}
+      else if (icls == FP_INFINITE)
+	{
+	  if (rcls >= FP_ZERO)
+	    __real__ res = __copysignf (M_PI_2, __real__ x);
+	  else
+	    __real__ res = __nanf ("");
+	  __imag__ res = __copysignf (0.0, __imag__ x);
+	}
+      else if (icls == FP_ZERO || icls == FP_INFINITE)
+	{
+	  __real__ res = __nanf ("");
+	  __imag__ res = __copysignf (0.0, __imag__ x);
+	}
+      else
+	{
+	  __real__ res = __nanf ("");
+	  __imag__ res = __nanf ("");
+	}
+    }
+  else if (rcls == FP_ZERO && icls == FP_ZERO)
+    {
+      res = x;
+    }
+  else
+    {
+      float r2, num, den;
+
+      r2 = __real__ x * __real__ x;
+
+      den = 1 - r2 - __imag__ x * __imag__ x;
+
+      __real__ res = 0.5 * __ieee754_atan2f (2.0 * __real__ x, den);
+
+      num = __imag__ x + 1.0;
+      num = r2 + num * num;
+
+      den = __imag__ x - 1.0;
+      den = r2 + den * den;
+
+      __imag__ res = 0.25 * __ieee754_logf (num / den);
+    }
+
+  return res;
+}
+#ifndef __catanf
+weak_alias (__catanf, catanf)
+#endif