Annotation of OpenXM_contrib/gmp/mpz/gcd_ui.c, Revision 1.1.1.3
1.1 maekawa 1: /* mpz_gcd_ui -- Calculate the greatest common divisior of two integers.
2:
1.1.1.3 ! ohara 3: Copyright 1994, 1996, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
1.1 maekawa 4:
5: This file is part of the GNU MP Library.
6:
7: The GNU MP Library is free software; you can redistribute it and/or modify
1.1.1.2 maekawa 8: it under the terms of the GNU Lesser General Public License as published by
9: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1 maekawa 10: option) any later version.
11:
12: The GNU MP Library is distributed in the hope that it will be useful, but
13: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1.1.1.2 maekawa 14: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
1.1 maekawa 15: License for more details.
16:
1.1.1.2 maekawa 17: You should have received a copy of the GNU Lesser General Public License
1.1 maekawa 18: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20: MA 02111-1307, USA. */
21:
1.1.1.2 maekawa 22: #include <stdio.h> /* for NULL */
1.1 maekawa 23: #include "gmp.h"
24: #include "gmp-impl.h"
25:
26: unsigned long int
27: mpz_gcd_ui (mpz_ptr w, mpz_srcptr u, unsigned long int v)
28: {
1.1.1.3 ! ohara 29: mp_size_t un;
1.1 maekawa 30: mp_limb_t res;
31:
1.1.1.3 ! ohara 32: #if GMP_NAIL_BITS != 0
! 33: if (v > GMP_NUMB_MAX)
! 34: {
! 35: mpz_t vz;
! 36: mp_limb_t vlimbs[2];
! 37: vlimbs[0] = v & GMP_NUMB_MASK;
! 38: vlimbs[1] = v >> GMP_NUMB_BITS;
! 39: PTR(vz) = vlimbs;
! 40: SIZ(vz) = 2;
! 41: mpz_gcd (w, u, vz);
! 42: return;
! 43: }
! 44: #endif
! 45:
! 46: un = ABSIZ(u);
1.1 maekawa 47:
1.1.1.3 ! ohara 48: if (un == 0)
1.1 maekawa 49: res = v;
50: else if (v == 0)
51: {
1.1.1.3 ! ohara 52: if (w != NULL)
1.1 maekawa 53: {
1.1.1.3 ! ohara 54: if (u != w)
! 55: {
! 56: MPZ_REALLOC (w, un);
! 57: MPN_COPY (PTR(w), PTR(u), un);
! 58: }
! 59: SIZ(w) = un;
1.1 maekawa 60: }
61: /* We can't return any useful result for gcd(big,0). */
1.1.1.3 ! ohara 62: return un > 1 ? 0 : PTR(u)[0];
1.1 maekawa 63: }
64: else
1.1.1.3 ! ohara 65: res = mpn_gcd_1 (PTR(u), un, (mp_limb_t) v);
1.1 maekawa 66:
67: if (w != NULL)
68: {
1.1.1.3 ! ohara 69: PTR(w)[0] = res;
! 70: SIZ(w) = res != 0;
1.1 maekawa 71: }
72: return res;
73: }
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