[331] | 1 | /*
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| 2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include <assert.h>
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| 11 | #include "internal/cryptlib.h"
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| 12 | #include "bn_lcl.h"
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| 13 |
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| 14 | #if defined(OPENSSL_NO_ASM) || !defined(OPENSSL_BN_ASM_PART_WORDS)
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| 15 | /*
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| 16 | * Here follows specialised variants of bn_add_words() and bn_sub_words().
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| 17 | * They have the property performing operations on arrays of different sizes.
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| 18 | * The sizes of those arrays is expressed through cl, which is the common
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| 19 | * length ( basically, min(len(a),len(b)) ), and dl, which is the delta
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| 20 | * between the two lengths, calculated as len(a)-len(b). All lengths are the
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| 21 | * number of BN_ULONGs... For the operations that require a result array as
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| 22 | * parameter, it must have the length cl+abs(dl). These functions should
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| 23 | * probably end up in bn_asm.c as soon as there are assembler counterparts
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| 24 | * for the systems that use assembler files.
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| 25 | */
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| 26 |
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| 27 | BN_ULONG bn_sub_part_words(BN_ULONG *r,
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| 28 | const BN_ULONG *a, const BN_ULONG *b,
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| 29 | int cl, int dl)
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| 30 | {
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| 31 | BN_ULONG c, t;
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| 32 |
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| 33 | assert(cl >= 0);
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| 34 | c = bn_sub_words(r, a, b, cl);
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| 35 |
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| 36 | if (dl == 0)
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| 37 | return c;
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| 38 |
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| 39 | r += cl;
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| 40 | a += cl;
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| 41 | b += cl;
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| 42 |
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| 43 | if (dl < 0) {
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| 44 | for (;;) {
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| 45 | t = b[0];
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| 46 | r[0] = (0 - t - c) & BN_MASK2;
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| 47 | if (t != 0)
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| 48 | c = 1;
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| 49 | if (++dl >= 0)
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| 50 | break;
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| 51 |
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| 52 | t = b[1];
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| 53 | r[1] = (0 - t - c) & BN_MASK2;
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| 54 | if (t != 0)
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| 55 | c = 1;
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| 56 | if (++dl >= 0)
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| 57 | break;
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| 58 |
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| 59 | t = b[2];
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| 60 | r[2] = (0 - t - c) & BN_MASK2;
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| 61 | if (t != 0)
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| 62 | c = 1;
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| 63 | if (++dl >= 0)
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| 64 | break;
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| 65 |
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| 66 | t = b[3];
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| 67 | r[3] = (0 - t - c) & BN_MASK2;
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| 68 | if (t != 0)
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| 69 | c = 1;
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| 70 | if (++dl >= 0)
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| 71 | break;
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| 72 |
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| 73 | b += 4;
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| 74 | r += 4;
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| 75 | }
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| 76 | } else {
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| 77 | int save_dl = dl;
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| 78 | while (c) {
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| 79 | t = a[0];
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| 80 | r[0] = (t - c) & BN_MASK2;
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| 81 | if (t != 0)
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| 82 | c = 0;
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| 83 | if (--dl <= 0)
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| 84 | break;
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| 85 |
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| 86 | t = a[1];
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| 87 | r[1] = (t - c) & BN_MASK2;
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| 88 | if (t != 0)
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| 89 | c = 0;
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| 90 | if (--dl <= 0)
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| 91 | break;
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| 92 |
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| 93 | t = a[2];
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| 94 | r[2] = (t - c) & BN_MASK2;
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| 95 | if (t != 0)
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| 96 | c = 0;
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| 97 | if (--dl <= 0)
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| 98 | break;
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| 99 |
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| 100 | t = a[3];
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| 101 | r[3] = (t - c) & BN_MASK2;
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| 102 | if (t != 0)
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| 103 | c = 0;
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| 104 | if (--dl <= 0)
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| 105 | break;
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| 106 |
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| 107 | save_dl = dl;
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| 108 | a += 4;
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| 109 | r += 4;
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| 110 | }
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| 111 | if (dl > 0) {
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| 112 | if (save_dl > dl) {
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| 113 | switch (save_dl - dl) {
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| 114 | case 1:
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| 115 | r[1] = a[1];
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| 116 | if (--dl <= 0)
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| 117 | break;
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| 118 | case 2:
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| 119 | r[2] = a[2];
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| 120 | if (--dl <= 0)
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| 121 | break;
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| 122 | case 3:
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| 123 | r[3] = a[3];
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| 124 | if (--dl <= 0)
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| 125 | break;
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| 126 | }
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| 127 | a += 4;
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| 128 | r += 4;
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| 129 | }
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| 130 | }
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| 131 | if (dl > 0) {
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| 132 | for (;;) {
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| 133 | r[0] = a[0];
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| 134 | if (--dl <= 0)
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| 135 | break;
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| 136 | r[1] = a[1];
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| 137 | if (--dl <= 0)
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| 138 | break;
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| 139 | r[2] = a[2];
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| 140 | if (--dl <= 0)
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| 141 | break;
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| 142 | r[3] = a[3];
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| 143 | if (--dl <= 0)
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| 144 | break;
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| 145 |
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| 146 | a += 4;
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| 147 | r += 4;
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| 148 | }
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| 149 | }
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| 150 | }
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| 151 | return c;
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| 152 | }
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| 153 | #endif
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| 154 |
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| 155 | BN_ULONG bn_add_part_words(BN_ULONG *r,
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| 156 | const BN_ULONG *a, const BN_ULONG *b,
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| 157 | int cl, int dl)
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| 158 | {
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| 159 | BN_ULONG c, l, t;
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| 160 |
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| 161 | assert(cl >= 0);
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| 162 | c = bn_add_words(r, a, b, cl);
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| 163 |
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| 164 | if (dl == 0)
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| 165 | return c;
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| 166 |
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| 167 | r += cl;
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| 168 | a += cl;
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| 169 | b += cl;
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| 170 |
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| 171 | if (dl < 0) {
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| 172 | int save_dl = dl;
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| 173 | while (c) {
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| 174 | l = (c + b[0]) & BN_MASK2;
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| 175 | c = (l < c);
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| 176 | r[0] = l;
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| 177 | if (++dl >= 0)
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| 178 | break;
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| 179 |
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| 180 | l = (c + b[1]) & BN_MASK2;
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| 181 | c = (l < c);
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| 182 | r[1] = l;
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| 183 | if (++dl >= 0)
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| 184 | break;
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| 185 |
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| 186 | l = (c + b[2]) & BN_MASK2;
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| 187 | c = (l < c);
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| 188 | r[2] = l;
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| 189 | if (++dl >= 0)
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| 190 | break;
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| 191 |
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| 192 | l = (c + b[3]) & BN_MASK2;
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| 193 | c = (l < c);
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| 194 | r[3] = l;
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| 195 | if (++dl >= 0)
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| 196 | break;
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| 197 |
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| 198 | save_dl = dl;
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| 199 | b += 4;
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| 200 | r += 4;
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| 201 | }
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| 202 | if (dl < 0) {
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| 203 | if (save_dl < dl) {
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| 204 | switch (dl - save_dl) {
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| 205 | case 1:
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| 206 | r[1] = b[1];
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| 207 | if (++dl >= 0)
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| 208 | break;
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| 209 | case 2:
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| 210 | r[2] = b[2];
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| 211 | if (++dl >= 0)
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| 212 | break;
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| 213 | case 3:
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| 214 | r[3] = b[3];
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| 215 | if (++dl >= 0)
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| 216 | break;
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| 217 | }
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| 218 | b += 4;
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| 219 | r += 4;
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| 220 | }
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| 221 | }
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| 222 | if (dl < 0) {
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| 223 | for (;;) {
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| 224 | r[0] = b[0];
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| 225 | if (++dl >= 0)
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| 226 | break;
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| 227 | r[1] = b[1];
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| 228 | if (++dl >= 0)
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| 229 | break;
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| 230 | r[2] = b[2];
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| 231 | if (++dl >= 0)
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| 232 | break;
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| 233 | r[3] = b[3];
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| 234 | if (++dl >= 0)
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| 235 | break;
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| 236 |
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| 237 | b += 4;
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| 238 | r += 4;
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| 239 | }
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| 240 | }
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| 241 | } else {
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| 242 | int save_dl = dl;
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| 243 | while (c) {
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| 244 | t = (a[0] + c) & BN_MASK2;
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| 245 | c = (t < c);
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| 246 | r[0] = t;
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| 247 | if (--dl <= 0)
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| 248 | break;
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| 249 |
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| 250 | t = (a[1] + c) & BN_MASK2;
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| 251 | c = (t < c);
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| 252 | r[1] = t;
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| 253 | if (--dl <= 0)
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| 254 | break;
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| 255 |
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| 256 | t = (a[2] + c) & BN_MASK2;
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| 257 | c = (t < c);
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| 258 | r[2] = t;
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| 259 | if (--dl <= 0)
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| 260 | break;
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| 261 |
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| 262 | t = (a[3] + c) & BN_MASK2;
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| 263 | c = (t < c);
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| 264 | r[3] = t;
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| 265 | if (--dl <= 0)
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| 266 | break;
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| 267 |
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| 268 | save_dl = dl;
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| 269 | a += 4;
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| 270 | r += 4;
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| 271 | }
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| 272 | if (dl > 0) {
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| 273 | if (save_dl > dl) {
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| 274 | switch (save_dl - dl) {
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| 275 | case 1:
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| 276 | r[1] = a[1];
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| 277 | if (--dl <= 0)
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| 278 | break;
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| 279 | case 2:
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| 280 | r[2] = a[2];
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| 281 | if (--dl <= 0)
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| 282 | break;
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| 283 | case 3:
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| 284 | r[3] = a[3];
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| 285 | if (--dl <= 0)
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| 286 | break;
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| 287 | }
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| 288 | a += 4;
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| 289 | r += 4;
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| 290 | }
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| 291 | }
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| 292 | if (dl > 0) {
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| 293 | for (;;) {
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| 294 | r[0] = a[0];
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| 295 | if (--dl <= 0)
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| 296 | break;
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| 297 | r[1] = a[1];
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| 298 | if (--dl <= 0)
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| 299 | break;
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| 300 | r[2] = a[2];
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| 301 | if (--dl <= 0)
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| 302 | break;
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| 303 | r[3] = a[3];
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| 304 | if (--dl <= 0)
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| 305 | break;
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| 306 |
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| 307 | a += 4;
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| 308 | r += 4;
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| 309 | }
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| 310 | }
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| 311 | }
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| 312 | return c;
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| 313 | }
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| 314 |
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| 315 | #ifdef BN_RECURSION
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| 316 | /*
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| 317 | * Karatsuba recursive multiplication algorithm (cf. Knuth, The Art of
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| 318 | * Computer Programming, Vol. 2)
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| 319 | */
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| 320 |
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| 321 | /*-
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| 322 | * r is 2*n2 words in size,
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| 323 | * a and b are both n2 words in size.
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| 324 | * n2 must be a power of 2.
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| 325 | * We multiply and return the result.
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| 326 | * t must be 2*n2 words in size
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| 327 | * We calculate
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| 328 | * a[0]*b[0]
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| 329 | * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
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| 330 | * a[1]*b[1]
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| 331 | */
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| 332 | /* dnX may not be positive, but n2/2+dnX has to be */
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| 333 | void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
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| 334 | int dna, int dnb, BN_ULONG *t)
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| 335 | {
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| 336 | int n = n2 / 2, c1, c2;
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| 337 | int tna = n + dna, tnb = n + dnb;
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| 338 | unsigned int neg, zero;
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| 339 | BN_ULONG ln, lo, *p;
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| 340 |
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| 341 | # ifdef BN_MUL_COMBA
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| 342 | # if 0
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| 343 | if (n2 == 4) {
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| 344 | bn_mul_comba4(r, a, b);
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| 345 | return;
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| 346 | }
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| 347 | # endif
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| 348 | /*
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| 349 | * Only call bn_mul_comba 8 if n2 == 8 and the two arrays are complete
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| 350 | * [steve]
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| 351 | */
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| 352 | if (n2 == 8 && dna == 0 && dnb == 0) {
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| 353 | bn_mul_comba8(r, a, b);
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| 354 | return;
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| 355 | }
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| 356 | # endif /* BN_MUL_COMBA */
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| 357 | /* Else do normal multiply */
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| 358 | if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL) {
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| 359 | bn_mul_normal(r, a, n2 + dna, b, n2 + dnb);
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| 360 | if ((dna + dnb) < 0)
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| 361 | memset(&r[2 * n2 + dna + dnb], 0,
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| 362 | sizeof(BN_ULONG) * -(dna + dnb));
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| 363 | return;
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| 364 | }
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| 365 | /* r=(a[0]-a[1])*(b[1]-b[0]) */
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| 366 | c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna);
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| 367 | c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n);
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| 368 | zero = neg = 0;
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| 369 | switch (c1 * 3 + c2) {
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| 370 | case -4:
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| 371 | bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */
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| 372 | bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
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| 373 | break;
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| 374 | case -3:
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| 375 | zero = 1;
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| 376 | break;
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| 377 | case -2:
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| 378 | bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */
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| 379 | bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); /* + */
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| 380 | neg = 1;
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| 381 | break;
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| 382 | case -1:
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| 383 | case 0:
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| 384 | case 1:
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| 385 | zero = 1;
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| 386 | break;
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| 387 | case 2:
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| 388 | bn_sub_part_words(t, a, &(a[n]), tna, n - tna); /* + */
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| 389 | bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
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| 390 | neg = 1;
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| 391 | break;
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| 392 | case 3:
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| 393 | zero = 1;
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| 394 | break;
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| 395 | case 4:
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| 396 | bn_sub_part_words(t, a, &(a[n]), tna, n - tna);
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| 397 | bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n);
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| 398 | break;
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| 399 | }
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| 400 |
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| 401 | # ifdef BN_MUL_COMBA
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| 402 | if (n == 4 && dna == 0 && dnb == 0) { /* XXX: bn_mul_comba4 could take
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| 403 | * extra args to do this well */
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| 404 | if (!zero)
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| 405 | bn_mul_comba4(&(t[n2]), t, &(t[n]));
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| 406 | else
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| 407 | memset(&t[n2], 0, sizeof(*t) * 8);
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| 408 |
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| 409 | bn_mul_comba4(r, a, b);
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| 410 | bn_mul_comba4(&(r[n2]), &(a[n]), &(b[n]));
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| 411 | } else if (n == 8 && dna == 0 && dnb == 0) { /* XXX: bn_mul_comba8 could
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| 412 | * take extra args to do
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| 413 | * this well */
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| 414 | if (!zero)
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| 415 | bn_mul_comba8(&(t[n2]), t, &(t[n]));
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| 416 | else
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| 417 | memset(&t[n2], 0, sizeof(*t) * 16);
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| 418 |
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| 419 | bn_mul_comba8(r, a, b);
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| 420 | bn_mul_comba8(&(r[n2]), &(a[n]), &(b[n]));
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| 421 | } else
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| 422 | # endif /* BN_MUL_COMBA */
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| 423 | {
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| 424 | p = &(t[n2 * 2]);
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| 425 | if (!zero)
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| 426 | bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p);
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| 427 | else
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| 428 | memset(&t[n2], 0, sizeof(*t) * n2);
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| 429 | bn_mul_recursive(r, a, b, n, 0, 0, p);
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| 430 | bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), n, dna, dnb, p);
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| 431 | }
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| 432 |
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| 433 | /*-
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| 434 | * t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
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| 435 | * r[10] holds (a[0]*b[0])
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| 436 | * r[32] holds (b[1]*b[1])
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| 437 | */
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| 438 |
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| 439 | c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));
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| 440 |
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| 441 | if (neg) { /* if t[32] is negative */
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| 442 | c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));
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| 443 | } else {
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| 444 | /* Might have a carry */
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| 445 | c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2));
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| 446 | }
|
---|
| 447 |
|
---|
| 448 | /*-
|
---|
| 449 | * t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
|
---|
| 450 | * r[10] holds (a[0]*b[0])
|
---|
| 451 | * r[32] holds (b[1]*b[1])
|
---|
| 452 | * c1 holds the carry bits
|
---|
| 453 | */
|
---|
| 454 | c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
|
---|
| 455 | if (c1) {
|
---|
| 456 | p = &(r[n + n2]);
|
---|
| 457 | lo = *p;
|
---|
| 458 | ln = (lo + c1) & BN_MASK2;
|
---|
| 459 | *p = ln;
|
---|
| 460 |
|
---|
| 461 | /*
|
---|
| 462 | * The overflow will stop before we over write words we should not
|
---|
| 463 | * overwrite
|
---|
| 464 | */
|
---|
| 465 | if (ln < (BN_ULONG)c1) {
|
---|
| 466 | do {
|
---|
| 467 | p++;
|
---|
| 468 | lo = *p;
|
---|
| 469 | ln = (lo + 1) & BN_MASK2;
|
---|
| 470 | *p = ln;
|
---|
| 471 | } while (ln == 0);
|
---|
| 472 | }
|
---|
| 473 | }
|
---|
| 474 | }
|
---|
| 475 |
|
---|
| 476 | /*
|
---|
| 477 | * n+tn is the word length t needs to be n*4 is size, as does r
|
---|
| 478 | */
|
---|
| 479 | /* tnX may not be negative but less than n */
|
---|
| 480 | void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
|
---|
| 481 | int tna, int tnb, BN_ULONG *t)
|
---|
| 482 | {
|
---|
| 483 | int i, j, n2 = n * 2;
|
---|
| 484 | int c1, c2, neg;
|
---|
| 485 | BN_ULONG ln, lo, *p;
|
---|
| 486 |
|
---|
| 487 | if (n < 8) {
|
---|
| 488 | bn_mul_normal(r, a, n + tna, b, n + tnb);
|
---|
| 489 | return;
|
---|
| 490 | }
|
---|
| 491 |
|
---|
| 492 | /* r=(a[0]-a[1])*(b[1]-b[0]) */
|
---|
| 493 | c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna);
|
---|
| 494 | c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n);
|
---|
| 495 | neg = 0;
|
---|
| 496 | switch (c1 * 3 + c2) {
|
---|
| 497 | case -4:
|
---|
| 498 | bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */
|
---|
| 499 | bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
|
---|
| 500 | break;
|
---|
| 501 | case -3:
|
---|
| 502 | /* break; */
|
---|
| 503 | case -2:
|
---|
| 504 | bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */
|
---|
| 505 | bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); /* + */
|
---|
| 506 | neg = 1;
|
---|
| 507 | break;
|
---|
| 508 | case -1:
|
---|
| 509 | case 0:
|
---|
| 510 | case 1:
|
---|
| 511 | /* break; */
|
---|
| 512 | case 2:
|
---|
| 513 | bn_sub_part_words(t, a, &(a[n]), tna, n - tna); /* + */
|
---|
| 514 | bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */
|
---|
| 515 | neg = 1;
|
---|
| 516 | break;
|
---|
| 517 | case 3:
|
---|
| 518 | /* break; */
|
---|
| 519 | case 4:
|
---|
| 520 | bn_sub_part_words(t, a, &(a[n]), tna, n - tna);
|
---|
| 521 | bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n);
|
---|
| 522 | break;
|
---|
| 523 | }
|
---|
| 524 | /*
|
---|
| 525 | * The zero case isn't yet implemented here. The speedup would probably
|
---|
| 526 | * be negligible.
|
---|
| 527 | */
|
---|
| 528 | # if 0
|
---|
| 529 | if (n == 4) {
|
---|
| 530 | bn_mul_comba4(&(t[n2]), t, &(t[n]));
|
---|
| 531 | bn_mul_comba4(r, a, b);
|
---|
| 532 | bn_mul_normal(&(r[n2]), &(a[n]), tn, &(b[n]), tn);
|
---|
| 533 | memset(&r[n2 + tn * 2], 0, sizeof(*r) * (n2 - tn * 2));
|
---|
| 534 | } else
|
---|
| 535 | # endif
|
---|
| 536 | if (n == 8) {
|
---|
| 537 | bn_mul_comba8(&(t[n2]), t, &(t[n]));
|
---|
| 538 | bn_mul_comba8(r, a, b);
|
---|
| 539 | bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb);
|
---|
| 540 | memset(&r[n2 + tna + tnb], 0, sizeof(*r) * (n2 - tna - tnb));
|
---|
| 541 | } else {
|
---|
| 542 | p = &(t[n2 * 2]);
|
---|
| 543 | bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p);
|
---|
| 544 | bn_mul_recursive(r, a, b, n, 0, 0, p);
|
---|
| 545 | i = n / 2;
|
---|
| 546 | /*
|
---|
| 547 | * If there is only a bottom half to the number, just do it
|
---|
| 548 | */
|
---|
| 549 | if (tna > tnb)
|
---|
| 550 | j = tna - i;
|
---|
| 551 | else
|
---|
| 552 | j = tnb - i;
|
---|
| 553 | if (j == 0) {
|
---|
| 554 | bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]),
|
---|
| 555 | i, tna - i, tnb - i, p);
|
---|
| 556 | memset(&r[n2 + i * 2], 0, sizeof(*r) * (n2 - i * 2));
|
---|
| 557 | } else if (j > 0) { /* eg, n == 16, i == 8 and tn == 11 */
|
---|
| 558 | bn_mul_part_recursive(&(r[n2]), &(a[n]), &(b[n]),
|
---|
| 559 | i, tna - i, tnb - i, p);
|
---|
| 560 | memset(&(r[n2 + tna + tnb]), 0,
|
---|
| 561 | sizeof(BN_ULONG) * (n2 - tna - tnb));
|
---|
| 562 | } else { /* (j < 0) eg, n == 16, i == 8 and tn == 5 */
|
---|
| 563 |
|
---|
| 564 | memset(&r[n2], 0, sizeof(*r) * n2);
|
---|
| 565 | if (tna < BN_MUL_RECURSIVE_SIZE_NORMAL
|
---|
| 566 | && tnb < BN_MUL_RECURSIVE_SIZE_NORMAL) {
|
---|
| 567 | bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb);
|
---|
| 568 | } else {
|
---|
| 569 | for (;;) {
|
---|
| 570 | i /= 2;
|
---|
| 571 | /*
|
---|
| 572 | * these simplified conditions work exclusively because
|
---|
| 573 | * difference between tna and tnb is 1 or 0
|
---|
| 574 | */
|
---|
| 575 | if (i < tna || i < tnb) {
|
---|
| 576 | bn_mul_part_recursive(&(r[n2]),
|
---|
| 577 | &(a[n]), &(b[n]),
|
---|
| 578 | i, tna - i, tnb - i, p);
|
---|
| 579 | break;
|
---|
| 580 | } else if (i == tna || i == tnb) {
|
---|
| 581 | bn_mul_recursive(&(r[n2]),
|
---|
| 582 | &(a[n]), &(b[n]),
|
---|
| 583 | i, tna - i, tnb - i, p);
|
---|
| 584 | break;
|
---|
| 585 | }
|
---|
| 586 | }
|
---|
| 587 | }
|
---|
| 588 | }
|
---|
| 589 | }
|
---|
| 590 |
|
---|
| 591 | /*-
|
---|
| 592 | * t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
|
---|
| 593 | * r[10] holds (a[0]*b[0])
|
---|
| 594 | * r[32] holds (b[1]*b[1])
|
---|
| 595 | */
|
---|
| 596 |
|
---|
| 597 | c1 = (int)(bn_add_words(t, r, &(r[n2]), n2));
|
---|
| 598 |
|
---|
| 599 | if (neg) { /* if t[32] is negative */
|
---|
| 600 | c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2));
|
---|
| 601 | } else {
|
---|
| 602 | /* Might have a carry */
|
---|
| 603 | c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2));
|
---|
| 604 | }
|
---|
| 605 |
|
---|
| 606 | /*-
|
---|
| 607 | * t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
|
---|
| 608 | * r[10] holds (a[0]*b[0])
|
---|
| 609 | * r[32] holds (b[1]*b[1])
|
---|
| 610 | * c1 holds the carry bits
|
---|
| 611 | */
|
---|
| 612 | c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2));
|
---|
| 613 | if (c1) {
|
---|
| 614 | p = &(r[n + n2]);
|
---|
| 615 | lo = *p;
|
---|
| 616 | ln = (lo + c1) & BN_MASK2;
|
---|
| 617 | *p = ln;
|
---|
| 618 |
|
---|
| 619 | /*
|
---|
| 620 | * The overflow will stop before we over write words we should not
|
---|
| 621 | * overwrite
|
---|
| 622 | */
|
---|
| 623 | if (ln < (BN_ULONG)c1) {
|
---|
| 624 | do {
|
---|
| 625 | p++;
|
---|
| 626 | lo = *p;
|
---|
| 627 | ln = (lo + 1) & BN_MASK2;
|
---|
| 628 | *p = ln;
|
---|
| 629 | } while (ln == 0);
|
---|
| 630 | }
|
---|
| 631 | }
|
---|
| 632 | }
|
---|
| 633 |
|
---|
| 634 | /*-
|
---|
| 635 | * a and b must be the same size, which is n2.
|
---|
| 636 | * r needs to be n2 words and t needs to be n2*2
|
---|
| 637 | */
|
---|
| 638 | void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
|
---|
| 639 | BN_ULONG *t)
|
---|
| 640 | {
|
---|
| 641 | int n = n2 / 2;
|
---|
| 642 |
|
---|
| 643 | bn_mul_recursive(r, a, b, n, 0, 0, &(t[0]));
|
---|
| 644 | if (n >= BN_MUL_LOW_RECURSIVE_SIZE_NORMAL) {
|
---|
| 645 | bn_mul_low_recursive(&(t[0]), &(a[0]), &(b[n]), n, &(t[n2]));
|
---|
| 646 | bn_add_words(&(r[n]), &(r[n]), &(t[0]), n);
|
---|
| 647 | bn_mul_low_recursive(&(t[0]), &(a[n]), &(b[0]), n, &(t[n2]));
|
---|
| 648 | bn_add_words(&(r[n]), &(r[n]), &(t[0]), n);
|
---|
| 649 | } else {
|
---|
| 650 | bn_mul_low_normal(&(t[0]), &(a[0]), &(b[n]), n);
|
---|
| 651 | bn_mul_low_normal(&(t[n]), &(a[n]), &(b[0]), n);
|
---|
| 652 | bn_add_words(&(r[n]), &(r[n]), &(t[0]), n);
|
---|
| 653 | bn_add_words(&(r[n]), &(r[n]), &(t[n]), n);
|
---|
| 654 | }
|
---|
| 655 | }
|
---|
| 656 |
|
---|
| 657 | /*-
|
---|
| 658 | * a and b must be the same size, which is n2.
|
---|
| 659 | * r needs to be n2 words and t needs to be n2*2
|
---|
| 660 | * l is the low words of the output.
|
---|
| 661 | * t needs to be n2*3
|
---|
| 662 | */
|
---|
| 663 | void bn_mul_high(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, BN_ULONG *l, int n2,
|
---|
| 664 | BN_ULONG *t)
|
---|
| 665 | {
|
---|
| 666 | int i, n;
|
---|
| 667 | int c1, c2;
|
---|
| 668 | int neg, oneg, zero;
|
---|
| 669 | BN_ULONG ll, lc, *lp, *mp;
|
---|
| 670 |
|
---|
| 671 | n = n2 / 2;
|
---|
| 672 |
|
---|
| 673 | /* Calculate (al-ah)*(bh-bl) */
|
---|
| 674 | neg = zero = 0;
|
---|
| 675 | c1 = bn_cmp_words(&(a[0]), &(a[n]), n);
|
---|
| 676 | c2 = bn_cmp_words(&(b[n]), &(b[0]), n);
|
---|
| 677 | switch (c1 * 3 + c2) {
|
---|
| 678 | case -4:
|
---|
| 679 | bn_sub_words(&(r[0]), &(a[n]), &(a[0]), n);
|
---|
| 680 | bn_sub_words(&(r[n]), &(b[0]), &(b[n]), n);
|
---|
| 681 | break;
|
---|
| 682 | case -3:
|
---|
| 683 | zero = 1;
|
---|
| 684 | break;
|
---|
| 685 | case -2:
|
---|
| 686 | bn_sub_words(&(r[0]), &(a[n]), &(a[0]), n);
|
---|
| 687 | bn_sub_words(&(r[n]), &(b[n]), &(b[0]), n);
|
---|
| 688 | neg = 1;
|
---|
| 689 | break;
|
---|
| 690 | case -1:
|
---|
| 691 | case 0:
|
---|
| 692 | case 1:
|
---|
| 693 | zero = 1;
|
---|
| 694 | break;
|
---|
| 695 | case 2:
|
---|
| 696 | bn_sub_words(&(r[0]), &(a[0]), &(a[n]), n);
|
---|
| 697 | bn_sub_words(&(r[n]), &(b[0]), &(b[n]), n);
|
---|
| 698 | neg = 1;
|
---|
| 699 | break;
|
---|
| 700 | case 3:
|
---|
| 701 | zero = 1;
|
---|
| 702 | break;
|
---|
| 703 | case 4:
|
---|
| 704 | bn_sub_words(&(r[0]), &(a[0]), &(a[n]), n);
|
---|
| 705 | bn_sub_words(&(r[n]), &(b[n]), &(b[0]), n);
|
---|
| 706 | break;
|
---|
| 707 | }
|
---|
| 708 |
|
---|
| 709 | oneg = neg;
|
---|
| 710 | /* t[10] = (a[0]-a[1])*(b[1]-b[0]) */
|
---|
| 711 | /* r[10] = (a[1]*b[1]) */
|
---|
| 712 | # ifdef BN_MUL_COMBA
|
---|
| 713 | if (n == 8) {
|
---|
| 714 | bn_mul_comba8(&(t[0]), &(r[0]), &(r[n]));
|
---|
| 715 | bn_mul_comba8(r, &(a[n]), &(b[n]));
|
---|
| 716 | } else
|
---|
| 717 | # endif
|
---|
| 718 | {
|
---|
| 719 | bn_mul_recursive(&(t[0]), &(r[0]), &(r[n]), n, 0, 0, &(t[n2]));
|
---|
| 720 | bn_mul_recursive(r, &(a[n]), &(b[n]), n, 0, 0, &(t[n2]));
|
---|
| 721 | }
|
---|
| 722 |
|
---|
| 723 | /*-
|
---|
| 724 | * s0 == low(al*bl)
|
---|
| 725 | * s1 == low(ah*bh)+low((al-ah)*(bh-bl))+low(al*bl)+high(al*bl)
|
---|
| 726 | * We know s0 and s1 so the only unknown is high(al*bl)
|
---|
| 727 | * high(al*bl) == s1 - low(ah*bh+s0+(al-ah)*(bh-bl))
|
---|
| 728 | * high(al*bl) == s1 - (r[0]+l[0]+t[0])
|
---|
| 729 | */
|
---|
| 730 | if (l != NULL) {
|
---|
| 731 | lp = &(t[n2 + n]);
|
---|
| 732 | bn_add_words(lp, &(r[0]), &(l[0]), n);
|
---|
| 733 | } else {
|
---|
| 734 | lp = &(r[0]);
|
---|
| 735 | }
|
---|
| 736 |
|
---|
| 737 | if (neg)
|
---|
| 738 | neg = (int)(bn_sub_words(&(t[n2]), lp, &(t[0]), n));
|
---|
| 739 | else {
|
---|
| 740 | bn_add_words(&(t[n2]), lp, &(t[0]), n);
|
---|
| 741 | neg = 0;
|
---|
| 742 | }
|
---|
| 743 |
|
---|
| 744 | if (l != NULL) {
|
---|
| 745 | bn_sub_words(&(t[n2 + n]), &(l[n]), &(t[n2]), n);
|
---|
| 746 | } else {
|
---|
| 747 | lp = &(t[n2 + n]);
|
---|
| 748 | mp = &(t[n2]);
|
---|
| 749 | for (i = 0; i < n; i++)
|
---|
| 750 | lp[i] = ((~mp[i]) + 1) & BN_MASK2;
|
---|
| 751 | }
|
---|
| 752 |
|
---|
| 753 | /*-
|
---|
| 754 | * s[0] = low(al*bl)
|
---|
| 755 | * t[3] = high(al*bl)
|
---|
| 756 | * t[10] = (a[0]-a[1])*(b[1]-b[0]) neg is the sign
|
---|
| 757 | * r[10] = (a[1]*b[1])
|
---|
| 758 | */
|
---|
| 759 | /*-
|
---|
| 760 | * R[10] = al*bl
|
---|
| 761 | * R[21] = al*bl + ah*bh + (a[0]-a[1])*(b[1]-b[0])
|
---|
| 762 | * R[32] = ah*bh
|
---|
| 763 | */
|
---|
| 764 | /*-
|
---|
| 765 | * R[1]=t[3]+l[0]+r[0](+-)t[0] (have carry/borrow)
|
---|
| 766 | * R[2]=r[0]+t[3]+r[1](+-)t[1] (have carry/borrow)
|
---|
| 767 | * R[3]=r[1]+(carry/borrow)
|
---|
| 768 | */
|
---|
| 769 | if (l != NULL) {
|
---|
| 770 | lp = &(t[n2]);
|
---|
| 771 | c1 = (int)(bn_add_words(lp, &(t[n2 + n]), &(l[0]), n));
|
---|
| 772 | } else {
|
---|
| 773 | lp = &(t[n2 + n]);
|
---|
| 774 | c1 = 0;
|
---|
| 775 | }
|
---|
| 776 | c1 += (int)(bn_add_words(&(t[n2]), lp, &(r[0]), n));
|
---|
| 777 | if (oneg)
|
---|
| 778 | c1 -= (int)(bn_sub_words(&(t[n2]), &(t[n2]), &(t[0]), n));
|
---|
| 779 | else
|
---|
| 780 | c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), &(t[0]), n));
|
---|
| 781 |
|
---|
| 782 | c2 = (int)(bn_add_words(&(r[0]), &(r[0]), &(t[n2 + n]), n));
|
---|
| 783 | c2 += (int)(bn_add_words(&(r[0]), &(r[0]), &(r[n]), n));
|
---|
| 784 | if (oneg)
|
---|
| 785 | c2 -= (int)(bn_sub_words(&(r[0]), &(r[0]), &(t[n]), n));
|
---|
| 786 | else
|
---|
| 787 | c2 += (int)(bn_add_words(&(r[0]), &(r[0]), &(t[n]), n));
|
---|
| 788 |
|
---|
| 789 | if (c1 != 0) { /* Add starting at r[0], could be +ve or -ve */
|
---|
| 790 | i = 0;
|
---|
| 791 | if (c1 > 0) {
|
---|
| 792 | lc = c1;
|
---|
| 793 | do {
|
---|
| 794 | ll = (r[i] + lc) & BN_MASK2;
|
---|
| 795 | r[i++] = ll;
|
---|
| 796 | lc = (lc > ll);
|
---|
| 797 | } while (lc);
|
---|
| 798 | } else {
|
---|
| 799 | lc = -c1;
|
---|
| 800 | do {
|
---|
| 801 | ll = r[i];
|
---|
| 802 | r[i++] = (ll - lc) & BN_MASK2;
|
---|
| 803 | lc = (lc > ll);
|
---|
| 804 | } while (lc);
|
---|
| 805 | }
|
---|
| 806 | }
|
---|
| 807 | if (c2 != 0) { /* Add starting at r[1] */
|
---|
| 808 | i = n;
|
---|
| 809 | if (c2 > 0) {
|
---|
| 810 | lc = c2;
|
---|
| 811 | do {
|
---|
| 812 | ll = (r[i] + lc) & BN_MASK2;
|
---|
| 813 | r[i++] = ll;
|
---|
| 814 | lc = (lc > ll);
|
---|
| 815 | } while (lc);
|
---|
| 816 | } else {
|
---|
| 817 | lc = -c2;
|
---|
| 818 | do {
|
---|
| 819 | ll = r[i];
|
---|
| 820 | r[i++] = (ll - lc) & BN_MASK2;
|
---|
| 821 | lc = (lc > ll);
|
---|
| 822 | } while (lc);
|
---|
| 823 | }
|
---|
| 824 | }
|
---|
| 825 | }
|
---|
| 826 | #endif /* BN_RECURSION */
|
---|
| 827 |
|
---|
| 828 | int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
|
---|
| 829 | {
|
---|
| 830 | int ret = 0;
|
---|
| 831 | int top, al, bl;
|
---|
| 832 | BIGNUM *rr;
|
---|
| 833 | #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
|
---|
| 834 | int i;
|
---|
| 835 | #endif
|
---|
| 836 | #ifdef BN_RECURSION
|
---|
| 837 | BIGNUM *t = NULL;
|
---|
| 838 | int j = 0, k;
|
---|
| 839 | #endif
|
---|
| 840 |
|
---|
| 841 | bn_check_top(a);
|
---|
| 842 | bn_check_top(b);
|
---|
| 843 | bn_check_top(r);
|
---|
| 844 |
|
---|
| 845 | al = a->top;
|
---|
| 846 | bl = b->top;
|
---|
| 847 |
|
---|
| 848 | if ((al == 0) || (bl == 0)) {
|
---|
| 849 | BN_zero(r);
|
---|
| 850 | return (1);
|
---|
| 851 | }
|
---|
| 852 | top = al + bl;
|
---|
| 853 |
|
---|
| 854 | BN_CTX_start(ctx);
|
---|
| 855 | if ((r == a) || (r == b)) {
|
---|
| 856 | if ((rr = BN_CTX_get(ctx)) == NULL)
|
---|
| 857 | goto err;
|
---|
| 858 | } else
|
---|
| 859 | rr = r;
|
---|
| 860 |
|
---|
| 861 | #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
|
---|
| 862 | i = al - bl;
|
---|
| 863 | #endif
|
---|
| 864 | #ifdef BN_MUL_COMBA
|
---|
| 865 | if (i == 0) {
|
---|
| 866 | # if 0
|
---|
| 867 | if (al == 4) {
|
---|
| 868 | if (bn_wexpand(rr, 8) == NULL)
|
---|
| 869 | goto err;
|
---|
| 870 | rr->top = 8;
|
---|
| 871 | bn_mul_comba4(rr->d, a->d, b->d);
|
---|
| 872 | goto end;
|
---|
| 873 | }
|
---|
| 874 | # endif
|
---|
| 875 | if (al == 8) {
|
---|
| 876 | if (bn_wexpand(rr, 16) == NULL)
|
---|
| 877 | goto err;
|
---|
| 878 | rr->top = 16;
|
---|
| 879 | bn_mul_comba8(rr->d, a->d, b->d);
|
---|
| 880 | goto end;
|
---|
| 881 | }
|
---|
| 882 | }
|
---|
| 883 | #endif /* BN_MUL_COMBA */
|
---|
| 884 | #ifdef BN_RECURSION
|
---|
| 885 | if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL)) {
|
---|
| 886 | if (i >= -1 && i <= 1) {
|
---|
| 887 | /*
|
---|
| 888 | * Find out the power of two lower or equal to the longest of the
|
---|
| 889 | * two numbers
|
---|
| 890 | */
|
---|
| 891 | if (i >= 0) {
|
---|
| 892 | j = BN_num_bits_word((BN_ULONG)al);
|
---|
| 893 | }
|
---|
| 894 | if (i == -1) {
|
---|
| 895 | j = BN_num_bits_word((BN_ULONG)bl);
|
---|
| 896 | }
|
---|
| 897 | j = 1 << (j - 1);
|
---|
| 898 | assert(j <= al || j <= bl);
|
---|
| 899 | k = j + j;
|
---|
| 900 | t = BN_CTX_get(ctx);
|
---|
| 901 | if (t == NULL)
|
---|
| 902 | goto err;
|
---|
| 903 | if (al > j || bl > j) {
|
---|
| 904 | if (bn_wexpand(t, k * 4) == NULL)
|
---|
| 905 | goto err;
|
---|
| 906 | if (bn_wexpand(rr, k * 4) == NULL)
|
---|
| 907 | goto err;
|
---|
| 908 | bn_mul_part_recursive(rr->d, a->d, b->d,
|
---|
| 909 | j, al - j, bl - j, t->d);
|
---|
| 910 | } else { /* al <= j || bl <= j */
|
---|
| 911 |
|
---|
| 912 | if (bn_wexpand(t, k * 2) == NULL)
|
---|
| 913 | goto err;
|
---|
| 914 | if (bn_wexpand(rr, k * 2) == NULL)
|
---|
| 915 | goto err;
|
---|
| 916 | bn_mul_recursive(rr->d, a->d, b->d, j, al - j, bl - j, t->d);
|
---|
| 917 | }
|
---|
| 918 | rr->top = top;
|
---|
| 919 | goto end;
|
---|
| 920 | }
|
---|
| 921 | # if 0
|
---|
| 922 | if (i == 1 && !BN_get_flags(b, BN_FLG_STATIC_DATA)) {
|
---|
| 923 | BIGNUM *tmp_bn = (BIGNUM *)b;
|
---|
| 924 | if (bn_wexpand(tmp_bn, al) == NULL)
|
---|
| 925 | goto err;
|
---|
| 926 | tmp_bn->d[bl] = 0;
|
---|
| 927 | bl++;
|
---|
| 928 | i--;
|
---|
| 929 | } else if (i == -1 && !BN_get_flags(a, BN_FLG_STATIC_DATA)) {
|
---|
| 930 | BIGNUM *tmp_bn = (BIGNUM *)a;
|
---|
| 931 | if (bn_wexpand(tmp_bn, bl) == NULL)
|
---|
| 932 | goto err;
|
---|
| 933 | tmp_bn->d[al] = 0;
|
---|
| 934 | al++;
|
---|
| 935 | i++;
|
---|
| 936 | }
|
---|
| 937 | if (i == 0) {
|
---|
| 938 | /* symmetric and > 4 */
|
---|
| 939 | /* 16 or larger */
|
---|
| 940 | j = BN_num_bits_word((BN_ULONG)al);
|
---|
| 941 | j = 1 << (j - 1);
|
---|
| 942 | k = j + j;
|
---|
| 943 | t = BN_CTX_get(ctx);
|
---|
| 944 | if (al == j) { /* exact multiple */
|
---|
| 945 | if (bn_wexpand(t, k * 2) == NULL)
|
---|
| 946 | goto err;
|
---|
| 947 | if (bn_wexpand(rr, k * 2) == NULL)
|
---|
| 948 | goto err;
|
---|
| 949 | bn_mul_recursive(rr->d, a->d, b->d, al, t->d);
|
---|
| 950 | } else {
|
---|
| 951 | if (bn_wexpand(t, k * 4) == NULL)
|
---|
| 952 | goto err;
|
---|
| 953 | if (bn_wexpand(rr, k * 4) == NULL)
|
---|
| 954 | goto err;
|
---|
| 955 | bn_mul_part_recursive(rr->d, a->d, b->d, al - j, j, t->d);
|
---|
| 956 | }
|
---|
| 957 | rr->top = top;
|
---|
| 958 | goto end;
|
---|
| 959 | }
|
---|
| 960 | # endif
|
---|
| 961 | }
|
---|
| 962 | #endif /* BN_RECURSION */
|
---|
| 963 | if (bn_wexpand(rr, top) == NULL)
|
---|
| 964 | goto err;
|
---|
| 965 | rr->top = top;
|
---|
| 966 | bn_mul_normal(rr->d, a->d, al, b->d, bl);
|
---|
| 967 |
|
---|
| 968 | #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
|
---|
| 969 | end:
|
---|
| 970 | #endif
|
---|
| 971 | rr->neg = a->neg ^ b->neg;
|
---|
| 972 | bn_correct_top(rr);
|
---|
| 973 | if (r != rr && BN_copy(r, rr) == NULL)
|
---|
| 974 | goto err;
|
---|
| 975 |
|
---|
| 976 | ret = 1;
|
---|
| 977 | err:
|
---|
| 978 | bn_check_top(r);
|
---|
| 979 | BN_CTX_end(ctx);
|
---|
| 980 | return (ret);
|
---|
| 981 | }
|
---|
| 982 |
|
---|
| 983 | void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
|
---|
| 984 | {
|
---|
| 985 | BN_ULONG *rr;
|
---|
| 986 |
|
---|
| 987 | if (na < nb) {
|
---|
| 988 | int itmp;
|
---|
| 989 | BN_ULONG *ltmp;
|
---|
| 990 |
|
---|
| 991 | itmp = na;
|
---|
| 992 | na = nb;
|
---|
| 993 | nb = itmp;
|
---|
| 994 | ltmp = a;
|
---|
| 995 | a = b;
|
---|
| 996 | b = ltmp;
|
---|
| 997 |
|
---|
| 998 | }
|
---|
| 999 | rr = &(r[na]);
|
---|
| 1000 | if (nb <= 0) {
|
---|
| 1001 | (void)bn_mul_words(r, a, na, 0);
|
---|
| 1002 | return;
|
---|
| 1003 | } else
|
---|
| 1004 | rr[0] = bn_mul_words(r, a, na, b[0]);
|
---|
| 1005 |
|
---|
| 1006 | for (;;) {
|
---|
| 1007 | if (--nb <= 0)
|
---|
| 1008 | return;
|
---|
| 1009 | rr[1] = bn_mul_add_words(&(r[1]), a, na, b[1]);
|
---|
| 1010 | if (--nb <= 0)
|
---|
| 1011 | return;
|
---|
| 1012 | rr[2] = bn_mul_add_words(&(r[2]), a, na, b[2]);
|
---|
| 1013 | if (--nb <= 0)
|
---|
| 1014 | return;
|
---|
| 1015 | rr[3] = bn_mul_add_words(&(r[3]), a, na, b[3]);
|
---|
| 1016 | if (--nb <= 0)
|
---|
| 1017 | return;
|
---|
| 1018 | rr[4] = bn_mul_add_words(&(r[4]), a, na, b[4]);
|
---|
| 1019 | rr += 4;
|
---|
| 1020 | r += 4;
|
---|
| 1021 | b += 4;
|
---|
| 1022 | }
|
---|
| 1023 | }
|
---|
| 1024 |
|
---|
| 1025 | void bn_mul_low_normal(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
|
---|
| 1026 | {
|
---|
| 1027 | bn_mul_words(r, a, n, b[0]);
|
---|
| 1028 |
|
---|
| 1029 | for (;;) {
|
---|
| 1030 | if (--n <= 0)
|
---|
| 1031 | return;
|
---|
| 1032 | bn_mul_add_words(&(r[1]), a, n, b[1]);
|
---|
| 1033 | if (--n <= 0)
|
---|
| 1034 | return;
|
---|
| 1035 | bn_mul_add_words(&(r[2]), a, n, b[2]);
|
---|
| 1036 | if (--n <= 0)
|
---|
| 1037 | return;
|
---|
| 1038 | bn_mul_add_words(&(r[3]), a, n, b[3]);
|
---|
| 1039 | if (--n <= 0)
|
---|
| 1040 | return;
|
---|
| 1041 | bn_mul_add_words(&(r[4]), a, n, b[4]);
|
---|
| 1042 | r += 4;
|
---|
| 1043 | b += 4;
|
---|
| 1044 | }
|
---|
| 1045 | }
|
---|