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Annotation of OpenXM_contrib/gmp/mpfr/pow.c, Revision 1.1

1.1     ! maekawa     1: /* mpfr_pow_ui, mpfr_ui_pow_ui -- compute the power of a floating-point
        !             2:                                   number or machine integer
        !             3:
        !             4: Copyright (C) 1999 PolKA project, Inria Lorraine and Loria
        !             5:
        !             6: This file is part of the MPFR Library.
        !             7:
        !             8: The MPFR Library is free software; you can redistribute it and/or modify
        !             9: it under the terms of the GNU Library General Public License as published by
        !            10: the Free Software Foundation; either version 2 of the License, or (at your
        !            11: option) any later version.
        !            12:
        !            13: The MPFR Library is distributed in the hope that it will be useful, but
        !            14: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
        !            15: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
        !            16: License for more details.
        !            17:
        !            18: You should have received a copy of the GNU Library General Public License
        !            19: along with the MPFR Library; see the file COPYING.LIB.  If not, write to
        !            20: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
        !            21: MA 02111-1307, USA. */
        !            22:
        !            23: #include <stdio.h>
        !            24: #include "gmp.h"
        !            25: #include "mpfr.h"
        !            26:
        !            27: /* sets x to y^n */
        !            28: void
        !            29: #if __STDC__
        !            30: mpfr_pow_ui (mpfr_ptr x, mpfr_srcptr y, unsigned int n, unsigned char rnd)
        !            31: #else
        !            32: mpfr_pow_ui (x, y, n, rnd)
        !            33:      mpfr_ptr x;
        !            34:      mpfr_srcptr y;
        !            35:      unsigned int n;
        !            36:      unsigned char rnd;
        !            37: #endif
        !            38: {
        !            39:   int i;
        !            40:
        !            41:   if (n==0) { mpfr_set_ui(x, 1, rnd); return; }
        !            42:   mpfr_set(x, y, rnd);
        !            43:   for (i=0;(1<<i)<=n;i++);
        !            44:   /* now 2^(i-1) <= n < 2^i */
        !            45:   for (i-=2; i>=0; i--) {
        !            46:     mpfr_mul(x, x, x, rnd);
        !            47:     if (n & (1<<i)) mpfr_mul(x, x, y, rnd);
        !            48:   }
        !            49:   return;
        !            50: }
        !            51:
        !            52: /* sets x to y^n */
        !            53: void mpfr_ui_pow_ui (mpfr_ptr x, unsigned int y, unsigned int n,
        !            54:                     unsigned char rnd)
        !            55: {
        !            56:   int i;
        !            57:
        !            58:   if (n==0) { mpfr_set_ui(x, 1, rnd); return; }
        !            59:   mpfr_set_ui(x, y, rnd);
        !            60:   for (i=0;(1<<i)<=n;i++);
        !            61:   /* now 2^(i-1) <= n < 2^i */
        !            62:   for (i-=2; i>=0; i--) {
        !            63:     mpfr_mul(x, x, x, rnd);
        !            64:     if (n & (1<<i)) mpfr_mul_ui(x, x, y, rnd);
        !            65:   }
        !            66:   return;
        !            67: }