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Annotation of OpenXM_contrib/gmp/mpz/tdiv_q_2exp.c, Revision 1.1.1.3

1.1       maekawa     1: /* mpz_tdiv_q_2exp -- Divide an integer by 2**CNT.  Round the quotient
                      2:    towards -infinity.
                      3:
1.1.1.3 ! ohara       4: Copyright 1991, 1993, 1994, 1996, 2001, 2002 Free Software Foundation, Inc.
1.1       maekawa     5:
                      6: This file is part of the GNU MP Library.
                      7:
                      8: The GNU MP Library is free software; you can redistribute it and/or modify
1.1.1.2   maekawa     9: it under the terms of the GNU Lesser General Public License as published by
                     10: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1       maekawa    11: option) any later version.
                     12:
                     13: The GNU MP Library is distributed in the hope that it will be useful, but
                     14: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1.1.1.2   maekawa    15: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
1.1       maekawa    16: License for more details.
                     17:
1.1.1.2   maekawa    18: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    19: along with the GNU MP 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 "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26: void
                     27: mpz_tdiv_q_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt)
                     28: {
                     29:   mp_size_t usize, wsize;
                     30:   mp_size_t limb_cnt;
                     31:
                     32:   usize = u->_mp_size;
1.1.1.3 ! ohara      33:   limb_cnt = cnt / GMP_NUMB_BITS;
1.1       maekawa    34:   wsize = ABS (usize) - limb_cnt;
                     35:   if (wsize <= 0)
                     36:     w->_mp_size = 0;
                     37:   else
                     38:     {
                     39:       mp_ptr wp;
                     40:       mp_srcptr up;
                     41:
                     42:       if (w->_mp_alloc < wsize)
                     43:        _mpz_realloc (w, wsize);
                     44:
                     45:       wp = w->_mp_d;
                     46:       up = u->_mp_d;
                     47:
1.1.1.3 ! ohara      48:       cnt %= GMP_NUMB_BITS;
1.1       maekawa    49:       if (cnt != 0)
                     50:        {
                     51:          mpn_rshift (wp, up + limb_cnt, wsize, cnt);
                     52:          wsize -= wp[wsize - 1] == 0;
                     53:        }
                     54:       else
                     55:        {
                     56:          MPN_COPY_INCR (wp, up + limb_cnt, wsize);
                     57:        }
                     58:
                     59:       w->_mp_size = usize >= 0 ? wsize : -wsize;
                     60:     }
                     61: }