Annotation of OpenXM_contrib/gmp/mpfr/pow.c, Revision 1.1.1.1
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: }
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