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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 (libgfor).
+
+Libgfor 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.
+
+Ligbfor 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 "config.h"
+#include "libgfortran.h"
+
+/* Uuse 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. */
+
+GFC_REAL_4
+prefix(pow_r4_i4) (GFC_REAL_4 a, GFC_INTEGER_4 b)
+{
+ GFC_REAL_4 pow, x;
+ GFC_INTEGER_4 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;
+}
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