/src/libgmp/mpz/fdiv_q_ui.c
Line | Count | Source (jump to first uncovered line) |
1 | | /* mpz_fdiv_q_ui -- Division rounding the quotient towards -infinity. |
2 | | The remainder gets the same sign as the denominator. |
3 | | |
4 | | Copyright 1994-1996, 1999, 2001, 2002, 2004, 2012 Free Software Foundation, |
5 | | Inc. |
6 | | |
7 | | This file is part of the GNU MP Library. |
8 | | |
9 | | The GNU MP Library is free software; you can redistribute it and/or modify |
10 | | it under the terms of either: |
11 | | |
12 | | * the GNU Lesser General Public License as published by the Free |
13 | | Software Foundation; either version 3 of the License, or (at your |
14 | | option) any later version. |
15 | | |
16 | | or |
17 | | |
18 | | * the GNU General Public License as published by the Free Software |
19 | | Foundation; either version 2 of the License, or (at your option) any |
20 | | later version. |
21 | | |
22 | | or both in parallel, as here. |
23 | | |
24 | | The GNU MP Library is distributed in the hope that it will be useful, but |
25 | | WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
26 | | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
27 | | for more details. |
28 | | |
29 | | You should have received copies of the GNU General Public License and the |
30 | | GNU Lesser General Public License along with the GNU MP Library. If not, |
31 | | see https://www.gnu.org/licenses/. */ |
32 | | |
33 | | #include "gmp-impl.h" |
34 | | |
35 | | unsigned long int |
36 | | mpz_fdiv_q_ui (mpz_ptr quot, mpz_srcptr dividend, unsigned long int divisor) |
37 | 8 | { |
38 | 8 | mp_size_t ns, nn, qn; |
39 | 8 | mp_ptr np, qp; |
40 | 8 | mp_limb_t rl; |
41 | | |
42 | 8 | if (UNLIKELY (divisor == 0)) |
43 | 0 | DIVIDE_BY_ZERO; |
44 | | |
45 | 8 | ns = SIZ(dividend); |
46 | 8 | if (ns == 0) |
47 | 0 | { |
48 | 0 | SIZ(quot) = 0; |
49 | 0 | return 0; |
50 | 0 | } |
51 | | |
52 | 8 | nn = ABS(ns); |
53 | 8 | qp = MPZ_REALLOC (quot, nn); |
54 | 8 | np = PTR(dividend); |
55 | | |
56 | | #if BITS_PER_ULONG > GMP_NUMB_BITS /* avoid warnings about shift amount */ |
57 | | if (divisor > GMP_NUMB_MAX) |
58 | | { |
59 | | mp_limb_t dp[2], rp[2]; |
60 | | |
61 | | if (nn == 1) /* tdiv_qr requirements; tested above for 0 */ |
62 | | { |
63 | | qp[0] = 0; |
64 | | rl = np[0]; |
65 | | qn = 1; /* a white lie, fixed below */ |
66 | | } |
67 | | else |
68 | | { |
69 | | dp[0] = divisor & GMP_NUMB_MASK; |
70 | | dp[1] = divisor >> GMP_NUMB_BITS; |
71 | | mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2); |
72 | | rl = rp[0] + (rp[1] << GMP_NUMB_BITS); |
73 | | qn = nn - 2 + 1; |
74 | | } |
75 | | |
76 | | if (rl != 0 && ns < 0) |
77 | | { |
78 | | mpn_incr_u (qp, (mp_limb_t) 1); |
79 | | rl = divisor - rl; |
80 | | } |
81 | | |
82 | | qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0; |
83 | | } |
84 | | else |
85 | | #endif |
86 | 8 | { |
87 | 8 | rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor); |
88 | | |
89 | 8 | if (rl != 0 && ns < 0) |
90 | 0 | { |
91 | 0 | mpn_incr_u (qp, (mp_limb_t) 1); |
92 | 0 | rl = divisor - rl; |
93 | 0 | } |
94 | | |
95 | 8 | qn = nn - (qp[nn - 1] == 0); |
96 | 8 | } |
97 | | |
98 | 8 | SIZ(quot) = ns >= 0 ? qn : -qn; |
99 | 8 | return rl; |
100 | 8 | } |