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+/* Support routines for the intrinsic power (**) operator.
+ Copyright 2004 Free Software Foundation, Inc.
+ Contributed by Paul Brook
+
+This file is part of the GNU Fortran 95 runtime library (libgfortran).
+
+Libgfortran is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public
+License as published by the Free Software Foundation; either
+version 2 of the License, or (at your option) any later version.
+
+In addition to the permissions in the GNU General Public License, the
+Free Software Foundation gives you unlimited permission to link the
+compiled version of this file into combinations with other programs,
+and to distribute those combinations without any restriction coming
+from the use of this file. (The General Public License restrictions
+do apply in other respects; for example, they cover modification of
+the file, and distribution when not linked into a combine
+executable.)
+
+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 General Public License for more details.
+
+You should have received a copy of the GNU General Public
+License along with libgfortran; see the file COPYING. If not,
+write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
+
+#include "config.h"
+#include "libgfortran.h"
+
+/* Use Binary Method to calculate the powi. This is not an optimal but
+ a simple and reasonable arithmetic. See section 4.6.3, "Evaluation of
+ Powers" of Donald E. Knuth, "Seminumerical Algorithms", Vol. 2, "The Art
+ of Computer Programming", 3rd Edition, 1998. */
+
+#if defined (HAVE_GFC_REAL_4) && defined (HAVE_GFC_INTEGER_16)
+
+GFC_REAL_4 pow_r4_i16 (GFC_REAL_4 a, GFC_INTEGER_16 b);
+export_proto(pow_r4_i16);
+
+GFC_REAL_4
+pow_r4_i16 (GFC_REAL_4 a, GFC_INTEGER_16 b)
+{
+ GFC_REAL_4 pow, x;
+ GFC_INTEGER_16 n, u;
+
+ n = b;
+ x = a;
+ pow = 1;
+ if (n != 0)
+ {
+ if (n < 0)
+ {
+
+ n = -n;
+ x = pow / x;
+ }
+ u = n;
+ for (;;)
+ {
+ if (u & 1)
+ pow *= x;
+ u >>= 1;
+ if (u)
+ x *= x;
+ else
+ break;
+ }
+ }
+ return pow;
+}
+
+#endif
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