Annotation of OpenXM_contrib/gmp/mpz/fdiv_q_ui.c, Revision 1.1.1.3
1.1 maekawa 1: /* mpz_fdiv_q_ui -- Division rounding the quotient towards -infinity.
2: The remainder gets the same sign as the denominator.
3:
1.1.1.3 ! ohara 4: Copyright 1994, 1995, 1996, 1999, 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: unsigned long int
27: mpz_fdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor)
28: {
1.1.1.3 ! ohara 29: mp_size_t ns, nn, qn;
! 30: mp_ptr np, qp;
! 31: mp_limb_t rl;
1.1 maekawa 32:
1.1.1.2 maekawa 33: if (divisor == 0)
34: DIVIDE_BY_ZERO;
35:
1.1.1.3 ! ohara 36: ns = SIZ(dividend);
! 37: if (ns == 0)
! 38: {
! 39: SIZ(quot) = 0;
! 40: return 0;
! 41: }
1.1 maekawa 42:
1.1.1.3 ! ohara 43: nn = ABS(ns);
! 44: MPZ_REALLOC (quot, nn);
! 45: qp = PTR(quot);
! 46: np = PTR(dividend);
1.1 maekawa 47:
1.1.1.3 ! ohara 48: #if GMP_NAIL_BITS != 0
! 49: if (divisor > GMP_NUMB_MAX)
! 50: {
! 51: mp_limb_t dp[2], rp[2];
1.1 maekawa 52:
1.1.1.3 ! ohara 53: if (nn == 1) /* tdiv_qr requirements; tested above for 0 */
! 54: {
! 55: qp[0] = 0;
! 56: rl = np[0];
! 57: qn = 1; /* a white lie, fixed below */
! 58: }
! 59: else
! 60: {
! 61: dp[0] = divisor & GMP_NUMB_MASK;
! 62: dp[1] = divisor >> GMP_NUMB_BITS;
! 63: mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);
! 64: rl = rp[0] + (rp[1] << GMP_NUMB_BITS);
! 65: qn = nn - 2 + 1;
! 66: }
! 67:
! 68: if (rl != 0 && ns < 0)
! 69: {
! 70: mpn_incr_u (qp, (mp_limb_t) 1);
! 71: rl = divisor - rl;
! 72: }
1.1 maekawa 73:
1.1.1.3 ! ohara 74: qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0;
1.1 maekawa 75: }
1.1.1.3 ! ohara 76: else
! 77: #endif
! 78: {
! 79: rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor);
1.1 maekawa 80:
1.1.1.3 ! ohara 81: if (rl != 0 && ns < 0)
! 82: {
! 83: mpn_incr_u (qp, (mp_limb_t) 1);
! 84: rl = divisor - rl;
! 85: }
! 86:
! 87: qn = nn - (qp[nn - 1] == 0);
! 88: }
1.1 maekawa 89:
1.1.1.3 ! ohara 90: SIZ(quot) = ns >= 0 ? qn : -qn;
! 91: return rl;
1.1 maekawa 92: }
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