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diff --git a/libgfortran/m4/cexp.m4 b/libgfortran/m4/cexp.m4
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+`/* Complex exponential functions
+   Copyright 2002, 2004 Free Software Foundation, Inc.
+   Contributed by Paul Brook <paul@nowt.org>
+
+This file is part of the GNU Fortran 95 runtime library (libgfor).
+
+Libgfortran 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.
+
+Libgfortran 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 libgfor; 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 <math.h>
+#include "libgfortran.h"'
+
+include(`mtype.m4')dnl
+
+/* z = a + ib  */
+/* Absolute value.  */
+real_type
+cabs`'q (complex_type z)
+{
+  return hypot`'q (REALPART (z), IMAGPART (z));
+}
+
+/* Complex argument.  The angle made with the +ve real axis.  Range 0-2pi.  */
+real_type
+carg`'q (complex_type z)
+{
+  real_type arg;
+
+  arg = atan2`'q (IMAGPART (z), REALPART (z));
+  if (arg < 0)
+    return arg + 2 * M_PI;
+  else
+    return arg;
+}
+
+/* exp(z) = exp(a)*(cos(b) + isin(b))  */
+complex_type
+cexp`'q (complex_type z)
+{
+  real_type a;
+  real_type b;
+  complex_type v;
+
+  a = REALPART (z);
+  b = IMAGPART (z);
+  COMPLEX_ASSIGN (v, cos`'q (b), sin`'q (b));
+  return exp`'q (a) * v;
+}
+
+/* log(z) = log (cabs(z)) + i*carg(z)  */
+complex_type
+clog`'q (complex_type z)
+{
+  complex_type v;
+
+  COMPLEX_ASSIGN (v, log`'q (cabs`'q (z)), carg`'q (z));
+  return v;
+}
+
+/* log10(z) = log10 (cabs(z)) + i*carg(z)  */
+complex_type
+clog10`'q (complex_type z)
+{
+  complex_type v;
+
+  COMPLEX_ASSIGN (v, log10`'q (cabs`'q (z)), carg`'q (z));
+  return v;
+}
+
+/* pow(base, power) = cexp (power * clog (base))  */
+complex_type
+cpow`'q (complex_type base, complex_type power)
+{
+  return cexp`'q (power * clog`'q (base));
+}
+
+/* sqrt(z).  Algorithm pulled from glibc.  */
+complex_type
+csqrt`'q (complex_type z)
+{
+  real_type re;
+  real_type im;
+  complex_type v;
+
+  re = REALPART (z);
+  im = IMAGPART (z);
+  if (im == 0.0)
+    {
+      if (re < 0.0)
+        {
+          COMPLEX_ASSIGN (v, 0.0, copysign`'q (sqrt`'q (-re), im));
+        }
+      else
+        {
+          COMPLEX_ASSIGN (v, fabs`'q (sqrt (re)),
+                          copysign`'q (0.0, im));
+        }
+    }
+  else if (re == 0.0)
+    {
+      real_type r;
+
+      r = sqrt`'q (0.5 * fabs (im));
+
+      COMPLEX_ASSIGN (v, copysign`'q (r, im), r);
+    }
+  else
+    {
+      real_type d, r, s;
+
+      d = hypot`'q (re, im);
+      /* Use the identity   2  Re res  Im res = Im x
+         to avoid cancellation error in  d +/- Re x.  */
+      if (re > 0)
+        {
+          r = sqrt`'q (0.5 * d + 0.5 * re);
+          s = (0.5 * im) / r;
+        }
+      else
+        {
+          s = sqrt`'q (0.5 * d - 0.5 * re);
+          r = fabs`'q ((0.5 * im) / s);
+        }
+
+      COMPLEX_ASSIGN (v, r, copysign`'q (s, im));
+    }
+  return v;
+}
+