1 /* Functions needed for bootstrapping the gmp build, based on mini-gmp.
2
3 Copyright 2001, 2002, 2004, 2011, 2012, 2015 Free Software Foundation, Inc.
4
5 This file is part of the GNU MP Library.
6
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of either:
9
10 * the GNU Lesser General Public License as published by the Free
11 Software Foundation; either version 3 of the License, or (at your
12 option) any later version.
13
14 or
15
16 * the GNU General Public License as published by the Free Software
17 Foundation; either version 2 of the License, or (at your option) any
18 later version.
19
20 or both in parallel, as here.
21
22 The GNU MP Library is distributed in the hope that it will be useful, but
23 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
25 for more details.
26
27 You should have received copies of the GNU General Public License and the
28 GNU Lesser General Public License along with the GNU MP Library. If not,
29 see https://www.gnu.org/licenses/. */
30
31
32 #define MINI_GMP_DONT_USE_FLOAT_H 1
33 #include "mini-gmp/mini-gmp.c"
34
35 #define MIN(l,o) ((l) < (o) ? (l) : (o))
36 #define PTR(x) ((x)->_mp_d)
37 #define SIZ(x) ((x)->_mp_size)
38
39 #define xmalloc gmp_default_alloc
40
41 int
isprime(unsigned long int t)42 isprime (unsigned long int t)
43 {
44 unsigned long int q, r, d;
45
46 if (t < 32)
47 return (0xa08a28acUL >> t) & 1;
48 if ((t & 1) == 0)
49 return 0;
50
51 if (t % 3 == 0)
52 return 0;
53 if (t % 5 == 0)
54 return 0;
55 if (t % 7 == 0)
56 return 0;
57
58 for (d = 11;;)
59 {
60 q = t / d;
61 r = t - q * d;
62 if (q < d)
63 return 1;
64 if (r == 0)
65 break;
66 d += 2;
67 q = t / d;
68 r = t - q * d;
69 if (q < d)
70 return 1;
71 if (r == 0)
72 break;
73 d += 4;
74 }
75 return 0;
76 }
77
78 int
log2_ceil(int n)79 log2_ceil (int n)
80 {
81 int e;
82 assert (n >= 1);
83 for (e = 0; ; e++)
84 if ((1 << e) >= n)
85 break;
86 return e;
87 }
88
89 /* Set inv to the inverse of d, in the style of invert_limb, ie. for
90 udiv_qrnnd_preinv. */
91 void
mpz_preinv_invert(mpz_t inv,const mpz_t d,int numb_bits)92 mpz_preinv_invert (mpz_t inv, const mpz_t d, int numb_bits)
93 {
94 mpz_t t;
95 int norm;
96 assert (SIZ(d) > 0);
97
98 norm = numb_bits - mpz_sizeinbase (d, 2);
99 assert (norm >= 0);
100 mpz_init (t);
101 mpz_setbit (t, 2*numb_bits - norm);
102 mpz_tdiv_q (inv, t, d);
103 mpz_clrbit (inv, numb_bits);
104
105 mpz_clear (t);
106 }
107
108 /* Calculate r satisfying r*d == 1 mod 2^n. */
109 void
mpz_invert_2exp(mpz_t r,const mpz_t a,unsigned long n)110 mpz_invert_2exp (mpz_t r, const mpz_t a, unsigned long n)
111 {
112 unsigned long i;
113 mpz_t inv, prod;
114
115 assert (mpz_odd_p (a));
116
117 mpz_init_set_ui (inv, 1L);
118 mpz_init (prod);
119
120 for (i = 1; i < n; i++)
121 {
122 mpz_mul (prod, inv, a);
123 if (mpz_tstbit (prod, i) != 0)
124 mpz_setbit (inv, i);
125 }
126
127 mpz_mul (prod, inv, a);
128 mpz_tdiv_r_2exp (prod, prod, n);
129 assert (mpz_cmp_ui (prod, 1L) == 0);
130
131 mpz_set (r, inv);
132
133 mpz_clear (inv);
134 mpz_clear (prod);
135 }
136
137 /* Calculate inv satisfying r*a == 1 mod 2^n. */
138 void
mpz_invert_ui_2exp(mpz_t r,unsigned long a,unsigned long n)139 mpz_invert_ui_2exp (mpz_t r, unsigned long a, unsigned long n)
140 {
141 mpz_t az;
142
143 mpz_init_set_ui (az, a);
144 mpz_invert_2exp (r, az, n);
145 mpz_clear (az);
146 }
147