1*86d7f5d3SJohn Marino /* mpz_fdiv_q_ui -- Division rounding the quotient towards -infinity.
2*86d7f5d3SJohn Marino The remainder gets the same sign as the denominator.
3*86d7f5d3SJohn Marino
4*86d7f5d3SJohn Marino Copyright 1994, 1995, 1996, 1999, 2001, 2002, 2004 Free Software Foundation,
5*86d7f5d3SJohn Marino Inc.
6*86d7f5d3SJohn Marino
7*86d7f5d3SJohn Marino This file is part of the GNU MP Library.
8*86d7f5d3SJohn Marino
9*86d7f5d3SJohn Marino The GNU MP Library is free software; you can redistribute it and/or modify
10*86d7f5d3SJohn Marino it under the terms of the GNU Lesser General Public License as published by
11*86d7f5d3SJohn Marino the Free Software Foundation; either version 3 of the License, or (at your
12*86d7f5d3SJohn Marino option) any later version.
13*86d7f5d3SJohn Marino
14*86d7f5d3SJohn Marino The GNU MP Library is distributed in the hope that it will be useful, but
15*86d7f5d3SJohn Marino WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16*86d7f5d3SJohn Marino or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17*86d7f5d3SJohn Marino License for more details.
18*86d7f5d3SJohn Marino
19*86d7f5d3SJohn Marino You should have received a copy of the GNU Lesser General Public License
20*86d7f5d3SJohn Marino along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
21*86d7f5d3SJohn Marino
22*86d7f5d3SJohn Marino #include "gmp.h"
23*86d7f5d3SJohn Marino #include "gmp-impl.h"
24*86d7f5d3SJohn Marino
25*86d7f5d3SJohn Marino unsigned long int
mpz_fdiv_q_ui(mpz_ptr quot,mpz_srcptr dividend,unsigned long int divisor)26*86d7f5d3SJohn Marino mpz_fdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor)
27*86d7f5d3SJohn Marino {
28*86d7f5d3SJohn Marino mp_size_t ns, nn, qn;
29*86d7f5d3SJohn Marino mp_ptr np, qp;
30*86d7f5d3SJohn Marino mp_limb_t rl;
31*86d7f5d3SJohn Marino
32*86d7f5d3SJohn Marino if (divisor == 0)
33*86d7f5d3SJohn Marino DIVIDE_BY_ZERO;
34*86d7f5d3SJohn Marino
35*86d7f5d3SJohn Marino ns = SIZ(dividend);
36*86d7f5d3SJohn Marino if (ns == 0)
37*86d7f5d3SJohn Marino {
38*86d7f5d3SJohn Marino SIZ(quot) = 0;
39*86d7f5d3SJohn Marino return 0;
40*86d7f5d3SJohn Marino }
41*86d7f5d3SJohn Marino
42*86d7f5d3SJohn Marino nn = ABS(ns);
43*86d7f5d3SJohn Marino MPZ_REALLOC (quot, nn);
44*86d7f5d3SJohn Marino qp = PTR(quot);
45*86d7f5d3SJohn Marino np = PTR(dividend);
46*86d7f5d3SJohn Marino
47*86d7f5d3SJohn Marino #if BITS_PER_ULONG > GMP_NUMB_BITS /* avoid warnings about shift amount */
48*86d7f5d3SJohn Marino if (divisor > GMP_NUMB_MAX)
49*86d7f5d3SJohn Marino {
50*86d7f5d3SJohn Marino mp_limb_t dp[2], rp[2];
51*86d7f5d3SJohn Marino
52*86d7f5d3SJohn Marino if (nn == 1) /* tdiv_qr requirements; tested above for 0 */
53*86d7f5d3SJohn Marino {
54*86d7f5d3SJohn Marino qp[0] = 0;
55*86d7f5d3SJohn Marino rl = np[0];
56*86d7f5d3SJohn Marino qn = 1; /* a white lie, fixed below */
57*86d7f5d3SJohn Marino }
58*86d7f5d3SJohn Marino else
59*86d7f5d3SJohn Marino {
60*86d7f5d3SJohn Marino dp[0] = divisor & GMP_NUMB_MASK;
61*86d7f5d3SJohn Marino dp[1] = divisor >> GMP_NUMB_BITS;
62*86d7f5d3SJohn Marino mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);
63*86d7f5d3SJohn Marino rl = rp[0] + (rp[1] << GMP_NUMB_BITS);
64*86d7f5d3SJohn Marino qn = nn - 2 + 1;
65*86d7f5d3SJohn Marino }
66*86d7f5d3SJohn Marino
67*86d7f5d3SJohn Marino if (rl != 0 && ns < 0)
68*86d7f5d3SJohn Marino {
69*86d7f5d3SJohn Marino mpn_incr_u (qp, (mp_limb_t) 1);
70*86d7f5d3SJohn Marino rl = divisor - rl;
71*86d7f5d3SJohn Marino }
72*86d7f5d3SJohn Marino
73*86d7f5d3SJohn Marino qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0;
74*86d7f5d3SJohn Marino }
75*86d7f5d3SJohn Marino else
76*86d7f5d3SJohn Marino #endif
77*86d7f5d3SJohn Marino {
78*86d7f5d3SJohn Marino rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor);
79*86d7f5d3SJohn Marino
80*86d7f5d3SJohn Marino if (rl != 0 && ns < 0)
81*86d7f5d3SJohn Marino {
82*86d7f5d3SJohn Marino mpn_incr_u (qp, (mp_limb_t) 1);
83*86d7f5d3SJohn Marino rl = divisor - rl;
84*86d7f5d3SJohn Marino }
85*86d7f5d3SJohn Marino
86*86d7f5d3SJohn Marino qn = nn - (qp[nn - 1] == 0);
87*86d7f5d3SJohn Marino }
88*86d7f5d3SJohn Marino
89*86d7f5d3SJohn Marino SIZ(quot) = ns >= 0 ? qn : -qn;
90*86d7f5d3SJohn Marino return rl;
91*86d7f5d3SJohn Marino }
92