Annotation of OpenXM_contrib/gmp/mpz/cdiv_q_ui.c, Revision 1.1.1.3
1.1 maekawa 1: /* mpz_cdiv_q_ui -- Division rounding the quotient towards +infinity. The
2: remainder gets the opposite sign as the denominator. In order to make it
3: always fit into the return type, the negative of the true remainder is
4: returned.
5:
1.1.1.3 ! ohara 6: Copyright 1994, 1996, 1999, 2001, 2002 Free Software Foundation, Inc.
1.1 maekawa 7:
8: This file is part of the GNU MP Library.
9:
10: The GNU MP Library is free software; you can redistribute it and/or modify
1.1.1.2 maekawa 11: it under the terms of the GNU Lesser General Public License as published by
12: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1 maekawa 13: option) any later version.
14:
15: The GNU MP Library is distributed in the hope that it will be useful, but
16: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
1.1.1.2 maekawa 17: or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
1.1 maekawa 18: License for more details.
19:
1.1.1.2 maekawa 20: You should have received a copy of the GNU Lesser General Public License
1.1 maekawa 21: along with the GNU MP Library; see the file COPYING.LIB. If not, write to
22: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
23: MA 02111-1307, USA. */
24:
25: #include "gmp.h"
26: #include "gmp-impl.h"
27:
28: unsigned long int
29: mpz_cdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor)
30: {
1.1.1.3 ! ohara 31: mp_size_t ns, nn, qn;
! 32: mp_ptr np, qp;
! 33: mp_limb_t rl;
1.1 maekawa 34:
1.1.1.2 maekawa 35: if (divisor == 0)
36: DIVIDE_BY_ZERO;
37:
1.1.1.3 ! ohara 38: ns = SIZ(dividend);
! 39: if (ns == 0)
! 40: {
! 41: SIZ(quot) = 0;
! 42: return 0;
! 43: }
1.1 maekawa 44:
1.1.1.3 ! ohara 45: nn = ABS(ns);
! 46: MPZ_REALLOC (quot, nn);
! 47: qp = PTR(quot);
! 48: np = PTR(dividend);
1.1 maekawa 49:
1.1.1.3 ! ohara 50: #if GMP_NAIL_BITS != 0
! 51: if (divisor > GMP_NUMB_MAX)
! 52: {
! 53: mp_limb_t dp[2], rp[2];
1.1 maekawa 54:
1.1.1.3 ! ohara 55: if (nn == 1) /* tdiv_qr requirements; tested above for 0 */
! 56: {
! 57: qp[0] = 0;
! 58: rl = np[0];
! 59: qn = 1; /* a white lie, fixed below */
! 60: }
! 61: else
! 62: {
! 63: dp[0] = divisor & GMP_NUMB_MASK;
! 64: dp[1] = divisor >> GMP_NUMB_BITS;
! 65: mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);
! 66: rl = rp[0] + (rp[1] << GMP_NUMB_BITS);
! 67: qn = nn - 2 + 1;
! 68: }
! 69:
! 70: if (rl != 0 && ns >= 0)
! 71: {
! 72: mpn_incr_u (qp, (mp_limb_t) 1);
! 73: rl = divisor - rl;
! 74: }
1.1 maekawa 75:
1.1.1.3 ! ohara 76: qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0;
1.1 maekawa 77: }
1.1.1.3 ! ohara 78: else
! 79: #endif
! 80: {
! 81: rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor);
1.1 maekawa 82:
1.1.1.3 ! ohara 83: if (rl != 0 && ns >= 0)
! 84: {
! 85: mpn_incr_u (qp, (mp_limb_t) 1);
! 86: rl = divisor - rl;
! 87: }
! 88:
! 89: qn = nn - (qp[nn - 1] == 0);
! 90: }
1.1 maekawa 91:
1.1.1.3 ! ohara 92: SIZ(quot) = ns >= 0 ? qn : -qn;
! 93: return rl;
1.1 maekawa 94: }
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