3 Copyright (C) 1994, 1996 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Library General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or (at your
10 option) any later version.
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
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
15 License for more details.
17 You should have received a copy of the GNU Library General Public License
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. */
26 /* Does not work for U == 0 or V == 0. It would be tough to make it work for
27 V == 0 since gcd(x,0) = x, and U does not generally fit in an mp_limb_t. */
30 mpn_gcd_1 (up, size, vlimb)
36 unsigned long int u_low_zero_bits, v_low_zero_bits;
40 ulimb = mpn_mod_1 (up, size, vlimb);
47 /* Need to eliminate low zero bits. */
48 count_trailing_zeros (u_low_zero_bits, ulimb);
49 ulimb >>= u_low_zero_bits;
51 count_trailing_zeros (v_low_zero_bits, vlimb);
52 vlimb >>= v_low_zero_bits;
54 while (ulimb != vlimb)
61 while ((ulimb & 1) == 0);
63 else /* vlimb > ulimb. */
68 while ((vlimb & 1) == 0);
72 return ulimb << MIN (u_low_zero_bits, v_low_zero_bits);