1/*
2 * Copyright (c) 2008-2016 Stefan Krah. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28
29#include "mpdecimal.h"
30#include <stdio.h>
31#include "bits.h"
32#include "constants.h"
33#include "fnt.h"
34#include "fourstep.h"
35#include "numbertheory.h"
36#include "sixstep.h"
37#include "umodarith.h"
38#include "convolute.h"
39
40
41/* Bignum: Fast convolution using the Number Theoretic Transform. Used for
42   the multiplication of very large coefficients. */
43
44
45/* Convolute the data in c1 and c2. Result is in c1. */
46int
47fnt_convolute(mpd_uint_t *c1, mpd_uint_t *c2, mpd_size_t n, int modnum)
48{
49    int (*fnt)(mpd_uint_t *, mpd_size_t, int);
50    int (*inv_fnt)(mpd_uint_t *, mpd_size_t, int);
51#ifdef PPRO
52    double dmod;
53    uint32_t dinvmod[3];
54#endif
55    mpd_uint_t n_inv, umod;
56    mpd_size_t i;
57
58
59    SETMODULUS(modnum);
60    n_inv = POWMOD(n, (umod-2));
61
62    if (ispower2(n)) {
63        if (n > SIX_STEP_THRESHOLD) {
64            fnt = six_step_fnt;
65            inv_fnt = inv_six_step_fnt;
66        }
67        else {
68            fnt = std_fnt;
69            inv_fnt = std_inv_fnt;
70        }
71    }
72    else {
73        fnt = four_step_fnt;
74        inv_fnt = inv_four_step_fnt;
75    }
76
77    if (!fnt(c1, n, modnum)) {
78        return 0;
79    }
80    if (!fnt(c2, n, modnum)) {
81        return 0;
82    }
83    for (i = 0; i < n-1; i += 2) {
84        mpd_uint_t x0 = c1[i];
85        mpd_uint_t y0 = c2[i];
86        mpd_uint_t x1 = c1[i+1];
87        mpd_uint_t y1 = c2[i+1];
88        MULMOD2(&x0, y0, &x1, y1);
89        c1[i] = x0;
90        c1[i+1] = x1;
91    }
92
93    if (!inv_fnt(c1, n, modnum)) {
94        return 0;
95    }
96    for (i = 0; i < n-3; i += 4) {
97        mpd_uint_t x0 = c1[i];
98        mpd_uint_t x1 = c1[i+1];
99        mpd_uint_t x2 = c1[i+2];
100        mpd_uint_t x3 = c1[i+3];
101        MULMOD2C(&x0, &x1, n_inv);
102        MULMOD2C(&x2, &x3, n_inv);
103        c1[i] = x0;
104        c1[i+1] = x1;
105        c1[i+2] = x2;
106        c1[i+3] = x3;
107    }
108
109    return 1;
110}
111
112/* Autoconvolute the data in c1. Result is in c1. */
113int
114fnt_autoconvolute(mpd_uint_t *c1, mpd_size_t n, int modnum)
115{
116    int (*fnt)(mpd_uint_t *, mpd_size_t, int);
117    int (*inv_fnt)(mpd_uint_t *, mpd_size_t, int);
118#ifdef PPRO
119    double dmod;
120    uint32_t dinvmod[3];
121#endif
122    mpd_uint_t n_inv, umod;
123    mpd_size_t i;
124
125
126    SETMODULUS(modnum);
127    n_inv = POWMOD(n, (umod-2));
128
129    if (ispower2(n)) {
130        if (n > SIX_STEP_THRESHOLD) {
131            fnt = six_step_fnt;
132            inv_fnt = inv_six_step_fnt;
133        }
134        else {
135            fnt = std_fnt;
136            inv_fnt = std_inv_fnt;
137        }
138    }
139    else {
140        fnt = four_step_fnt;
141        inv_fnt = inv_four_step_fnt;
142    }
143
144    if (!fnt(c1, n, modnum)) {
145        return 0;
146    }
147    for (i = 0; i < n-1; i += 2) {
148        mpd_uint_t x0 = c1[i];
149        mpd_uint_t x1 = c1[i+1];
150        MULMOD2(&x0, x0, &x1, x1);
151        c1[i] = x0;
152        c1[i+1] = x1;
153    }
154
155    if (!inv_fnt(c1, n, modnum)) {
156        return 0;
157    }
158    for (i = 0; i < n-3; i += 4) {
159        mpd_uint_t x0 = c1[i];
160        mpd_uint_t x1 = c1[i+1];
161        mpd_uint_t x2 = c1[i+2];
162        mpd_uint_t x3 = c1[i+3];
163        MULMOD2C(&x0, &x1, n_inv);
164        MULMOD2C(&x2, &x3, n_inv);
165        c1[i] = x0;
166        c1[i+1] = x1;
167        c1[i+2] = x2;
168        c1[i+3] = x3;
169    }
170
171    return 1;
172}
173
174
175