3d1f465aff
2007-03-04 Thomas Koenig <Thomas.Koenig@online.de> PR libfortran/30981 * m4/pow_m4: Use appropriate unsigned int type for u. * generated/pow_c10_i16.c: Regenerated. * generated/pow_c10_i4.c: Regenerated. * generated/pow_c10_i8.c: Regenerated. * generated/pow_c16_i16.c: Regenerated. * generated/pow_c16_i4.c: Regenerated. * generated/pow_c16_i8.c: Regenerated. * generated/pow_c4_i16.c: Regenerated. * generated/pow_c4_i4.c: Regenerated. * generated/pow_c4_i8.c: Regenerated. * generated/pow_c8_i16.c: Regenerated. * generated/pow_c8_i4.c: Regenerated. * generated/pow_c8_i8.c: Regenerated. * generated/pow_i16_i16.c: Regenerated. * generated/pow_i16_i4.c: Regenerated. * generated/pow_i16_i8.c: Regenerated. * generated/pow_i4_i16.c: Regenerated. * generated/pow_i4_i4.c: Regenerated. * generated/pow_i4_i8.c: Regenerated. * generated/pow_i8_i16.c: Regenerated. * generated/pow_i8_i4.c: Regenerated. * generated/pow_i8_i8.c: Regenerated. * generated/pow_r10_i16.c: Regenerated. * generated/pow_r10_i4.c: Regenerated. * generated/pow_r10_i8.c: Regenerated. * generated/pow_r16_i16.c: Regenerated. * generated/pow_r16_i4.c: Regenerated. * generated/pow_r16_i8.c: Regenerated. * generated/pow_r4_i16.c: Regenerated. * generated/pow_r4_i4.c: Regenerated. * generated/pow_r4_i8.c: Regenerated. * generated/pow_r8_i16.c: Regenerated. * generated/pow_r8_i4.c: Regenerated. * generated/pow_r8_i8.c: Regenerated. 2007-03-04 Thomas Koenig <Thomas.Koenig@online.de> PR libfortran/30981 * gfortran.dg/integer_exponentiation_1.f90: New test. From-SVN: r122522
81 lines
2.2 KiB
C
81 lines
2.2 KiB
C
/* Support routines for the intrinsic power (**) operator.
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Copyright 2004 Free Software Foundation, Inc.
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Contributed by Paul Brook
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This file is part of the GNU Fortran 95 runtime library (libgfortran).
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Libgfortran is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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In addition to the permissions in the GNU General Public License, the
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Free Software Foundation gives you unlimited permission to link the
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compiled version of this file into combinations with other programs,
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and to distribute those combinations without any restriction coming
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from the use of this file. (The General Public License restrictions
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do apply in other respects; for example, they cover modification of
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the file, and distribution when not linked into a combine
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executable.)
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Libgfortran is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public
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License along with libgfortran; see the file COPYING. If not,
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write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#include "config.h"
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#include "libgfortran.h"
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/* Use Binary Method to calculate the powi. This is not an optimal but
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a simple and reasonable arithmetic. See section 4.6.3, "Evaluation of
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Powers" of Donald E. Knuth, "Seminumerical Algorithms", Vol. 2, "The Art
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of Computer Programming", 3rd Edition, 1998. */
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#if defined (HAVE_GFC_REAL_8) && defined (HAVE_GFC_INTEGER_4)
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GFC_REAL_8 pow_r8_i4 (GFC_REAL_8 a, GFC_INTEGER_4 b);
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export_proto(pow_r8_i4);
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GFC_REAL_8
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pow_r8_i4 (GFC_REAL_8 a, GFC_INTEGER_4 b)
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{
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GFC_REAL_8 pow, x;
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GFC_INTEGER_4 n;
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GFC_UINTEGER_4 u;
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n = b;
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x = a;
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pow = 1;
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if (n != 0)
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{
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if (n < 0)
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{
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u = -n;
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x = pow / x;
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}
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else
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{
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u = n;
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}
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for (;;)
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{
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if (u & 1)
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pow *= x;
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u >>= 1;
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if (u)
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x *= x;
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else
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break;
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}
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}
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return pow;
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}
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#endif
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