Annotation of OpenXM/src/kan96xx/gmp-2.0.2-ssh-2/mpz/tdiv_q_2exp.c, Revision 1.1
1.1 ! takayama 1: /* mpz_tdiv_q_2exp -- Divide an integer by 2**CNT. Round the quotient
! 2: towards -infinity.
! 3:
! 4: Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
! 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
! 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 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
! 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 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: #if __STDC__
! 28: mpz_tdiv_q_2exp (mpz_ptr w, mpz_srcptr u, unsigned long int cnt)
! 29: #else
! 30: mpz_tdiv_q_2exp (w, u, cnt)
! 31: mpz_ptr w;
! 32: mpz_srcptr u;
! 33: unsigned long int cnt;
! 34: #endif
! 35: {
! 36: mp_size_t usize, wsize;
! 37: mp_size_t limb_cnt;
! 38:
! 39: usize = u->_mp_size;
! 40: limb_cnt = cnt / BITS_PER_MP_LIMB;
! 41: wsize = ABS (usize) - limb_cnt;
! 42: if (wsize <= 0)
! 43: w->_mp_size = 0;
! 44: else
! 45: {
! 46: mp_ptr wp;
! 47: mp_srcptr up;
! 48:
! 49: if (w->_mp_alloc < wsize)
! 50: _mpz_realloc (w, wsize);
! 51:
! 52: wp = w->_mp_d;
! 53: up = u->_mp_d;
! 54:
! 55: cnt %= BITS_PER_MP_LIMB;
! 56: if (cnt != 0)
! 57: {
! 58: mpn_rshift (wp, up + limb_cnt, wsize, cnt);
! 59: wsize -= wp[wsize - 1] == 0;
! 60: }
! 61: else
! 62: {
! 63: MPN_COPY_INCR (wp, up + limb_cnt, wsize);
! 64: }
! 65:
! 66: w->_mp_size = usize >= 0 ? wsize : -wsize;
! 67: }
! 68: }
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