mpi-genesis 1
mpi-genesis 2 * Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
mpi-genesis 3 * Copyright (C) 1994, 1996 Free Software Foundation, Inc.
mpi-genesis 4 *
mpi-genesis 5 * This file is part of GnuPG.
mpi-genesis 6 *
mpi-genesis 7 * GnuPG is free software; you can redistribute it and/or modify
mpi-genesis 8 * it under the terms of the GNU General Public License as published by
mpi-genesis 9 * the Free Software Foundation; either version 3 of the License, or
mpi-genesis 10 * (at your option) any later version.
mpi-genesis 11 *
mpi-genesis 12 * GnuPG is distributed in the hope that it will be useful,
mpi-genesis 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
mpi-genesis 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
mpi-genesis 15 * GNU General Public License for more details.
mpi-genesis 16 *
mpi-genesis 17 * You should have received a copy of the GNU General Public License
mpi-genesis 18 * along with this program; if not, see <http:
mpi-genesis 19 *
mpi-genesis 20 * Note: This code is heavily based on the GNU MP Library.
mpi-genesis 21 * Actually it's the same code with only minor changes in the
mpi-genesis 22 * way the data is stored; this is to support the abstraction
mpi-genesis 23 * of an optional secure memory allocation which may be used
mpi-genesis 24 * to avoid revealing of sensitive data due to paging etc.
mpi-genesis 25 * The GNU MP Library itself is published under the LGPL;
mpi-genesis 26 * however I decided to publish this code under the plain GPL.
mpi-genesis 27 */
mpi-genesis 28
mpi-genesis 29 #include <config.h>
mpi-genesis 30 #include <stdio.h>
mpi-genesis 31 #include <stdlib.h>
mpi-genesis 32
mpi-genesis 33 #include "mpi-internal.h"
mpi-genesis 34
mpi-genesis 35
mpi-genesis 36
mpi-genesis 37 * Add the unsigned integer V to the mpi-integer U and store the
mpi-genesis 38 * result in W. U and V may be the same.
mpi-genesis 39 */
mpi-genesis 40 void
mpi-genesis 41 mpi_add_ui(MPI w, MPI u, unsigned long v )
mpi-genesis 42 {
mpi-genesis 43 mpi_ptr_t wp, up;
mpi-genesis 44 mpi_size_t usize, wsize;
mpi-genesis 45 int usign, wsign;
mpi-genesis 46
mpi-genesis 47 usize = u->nlimbs;
mpi-genesis 48 usign = u->sign;
mpi-genesis 49 wsign = 0;
mpi-genesis 50
mpi-genesis 51
mpi-genesis 52 wsize = usize + 1;
mpi-genesis 53 if( w->alloced < wsize )
mpi-genesis 54 mpi_resize(w, wsize);
mpi-genesis 55
mpi-genesis 56
mpi-genesis 57 up = u->d;
mpi-genesis 58 wp = w->d;
mpi-genesis 59
mpi-genesis 60 if( !usize ) {
mpi-genesis 61 wp[0] = v;
mpi-genesis 62 wsize = v? 1:0;
mpi-genesis 63 }
mpi-genesis 64 else if( !usign ) {
mpi-genesis 65 mpi_limb_t cy;
mpi-genesis 66 cy = mpihelp_add_1(wp, up, usize, v);
mpi-genesis 67 wp[usize] = cy;
mpi-genesis 68 wsize = usize + cy;
mpi-genesis 69 }
mpi-genesis 70 else {
mpi-genesis 71 * which operand to subtract from which. */
mpi-genesis 72 if( usize == 1 && up[0] < v ) {
mpi-genesis 73 wp[0] = v - up[0];
mpi-genesis 74 wsize = 1;
mpi-genesis 75 }
mpi-genesis 76 else {
mpi-genesis 77 mpihelp_sub_1(wp, up, usize, v);
mpi-genesis 78
mpi-genesis 79 wsize = usize - (wp[usize-1]==0);
mpi-genesis 80 wsign = 1;
mpi-genesis 81 }
mpi-genesis 82 }
mpi-genesis 83
mpi-genesis 84 w->nlimbs = wsize;
mpi-genesis 85 w->sign = wsign;
mpi-genesis 86 }
mpi-genesis 87
mpi-genesis 88
mpi-genesis 89 void
mpi-genesis 90 mpi_add(MPI w, MPI u, MPI v)
mpi-genesis 91 {
mpi-genesis 92 mpi_ptr_t wp, up, vp;
mpi-genesis 93 mpi_size_t usize, vsize, wsize;
mpi-genesis 94 int usign, vsign, wsign;
mpi-genesis 95
mpi-genesis 96 if( u->nlimbs < v->nlimbs ) {
mpi-genesis 97 usize = v->nlimbs;
mpi-genesis 98 usign = v->sign;
mpi-genesis 99 vsize = u->nlimbs;
mpi-genesis 100 vsign = u->sign;
mpi-genesis 101 wsize = usize + 1;
mpi-genesis 102 RESIZE_IF_NEEDED(w, wsize);
mpi-genesis 103
mpi-genesis 104 up = v->d;
mpi-genesis 105 vp = u->d;
mpi-genesis 106 }
mpi-genesis 107 else {
mpi-genesis 108 usize = u->nlimbs;
mpi-genesis 109 usign = u->sign;
mpi-genesis 110 vsize = v->nlimbs;
mpi-genesis 111 vsign = v->sign;
mpi-genesis 112 wsize = usize + 1;
mpi-genesis 113 RESIZE_IF_NEEDED(w, wsize);
mpi-genesis 114
mpi-genesis 115 up = u->d;
mpi-genesis 116 vp = v->d;
mpi-genesis 117 }
mpi-genesis 118 wp = w->d;
mpi-genesis 119 wsign = 0;
mpi-genesis 120
mpi-genesis 121 if( !vsize ) {
mpi-genesis 122 MPN_COPY(wp, up, usize );
mpi-genesis 123 wsize = usize;
mpi-genesis 124 wsign = usign;
mpi-genesis 125 }
mpi-genesis 126 else if( usign != vsign ) {
mpi-genesis 127
mpi-genesis 128 if( usize != vsize ) {
mpi-genesis 129 mpihelp_sub(wp, up, usize, vp, vsize);
mpi-genesis 130 wsize = usize;
mpi-genesis 131 MPN_NORMALIZE(wp, wsize);
mpi-genesis 132 wsign = usign;
mpi-genesis 133 }
mpi-genesis 134 else if( mpihelp_cmp(up, vp, usize) < 0 ) {
mpi-genesis 135 mpihelp_sub_n(wp, vp, up, usize);
mpi-genesis 136 wsize = usize;
mpi-genesis 137 MPN_NORMALIZE(wp, wsize);
mpi-genesis 138 if( !usign )
mpi-genesis 139 wsign = 1;
mpi-genesis 140 }
mpi-genesis 141 else {
mpi-genesis 142 mpihelp_sub_n(wp, up, vp, usize);
mpi-genesis 143 wsize = usize;
mpi-genesis 144 MPN_NORMALIZE(wp, wsize);
mpi-genesis 145 if( usign )
mpi-genesis 146 wsign = 1;
mpi-genesis 147 }
mpi-genesis 148 }
mpi-genesis 149 else {
mpi-genesis 150 mpi_limb_t cy = mpihelp_add(wp, up, usize, vp, vsize);
mpi-genesis 151 wp[usize] = cy;
mpi-genesis 152 wsize = usize + cy;
mpi-genesis 153 if( usign )
mpi-genesis 154 wsign = 1;
mpi-genesis 155 }
mpi-genesis 156
mpi-genesis 157 w->nlimbs = wsize;
mpi-genesis 158 w->sign = wsign;
mpi-genesis 159 }
mpi-genesis 160
mpi-genesis 161
mpi-genesis 162
mpi-genesis 163 * Subtract the unsigned integer V from the mpi-integer U and store the
mpi-genesis 164 * result in W.
mpi-genesis 165 */
mpi-genesis 166 void
mpi-genesis 167 mpi_sub_ui(MPI w, MPI u, unsigned long v )
mpi-genesis 168 {
mpi-genesis 169 mpi_ptr_t wp, up;
mpi-genesis 170 mpi_size_t usize, wsize;
mpi-genesis 171 int usign, wsign;
mpi-genesis 172
mpi-genesis 173 usize = u->nlimbs;
mpi-genesis 174 usign = u->sign;
mpi-genesis 175 wsign = 0;
mpi-genesis 176
mpi-genesis 177
mpi-genesis 178 wsize = usize + 1;
mpi-genesis 179 if( w->alloced < wsize )
mpi-genesis 180 mpi_resize(w, wsize);
mpi-genesis 181
mpi-genesis 182
mpi-genesis 183 up = u->d;
mpi-genesis 184 wp = w->d;
mpi-genesis 185
mpi-genesis 186 if( !usize ) {
mpi-genesis 187 wp[0] = v;
mpi-genesis 188 wsize = v? 1:0;
mpi-genesis 189 wsign = 1;
mpi-genesis 190 }
mpi-genesis 191 else if( usign ) {
mpi-genesis 192 mpi_limb_t cy;
mpi-genesis 193 cy = mpihelp_add_1(wp, up, usize, v);
mpi-genesis 194 wp[usize] = cy;
mpi-genesis 195 wsize = usize + cy;
mpi-genesis 196 }
mpi-genesis 197 else {
mpi-genesis 198 * which operand to subtract from which. */
mpi-genesis 199 if( usize == 1 && up[0] < v ) {
mpi-genesis 200 wp[0] = v - up[0];
mpi-genesis 201 wsize = 1;
mpi-genesis 202 wsign = 1;
mpi-genesis 203 }
mpi-genesis 204 else {
mpi-genesis 205 mpihelp_sub_1(wp, up, usize, v);
mpi-genesis 206
mpi-genesis 207 wsize = usize - (wp[usize-1]==0);
mpi-genesis 208 }
mpi-genesis 209 }
mpi-genesis 210
mpi-genesis 211 w->nlimbs = wsize;
mpi-genesis 212 w->sign = wsign;
mpi-genesis 213 }
mpi-genesis 214
mpi-genesis 215 void
mpi-genesis 216 mpi_sub(MPI w, MPI u, MPI v)
mpi-genesis 217 {
mpi-genesis 218 if( w == v ) {
mpi-genesis 219 MPI vv = mpi_copy(v);
mpi-genesis 220 vv->sign = !vv->sign;
mpi-genesis 221 mpi_add( w, u, vv );
mpi-genesis 222 mpi_free(vv);
mpi-genesis 223 }
mpi-genesis 224 else {
mpi-genesis 225
mpi-genesis 226 v->sign = !v->sign;
mpi-genesis 227 mpi_add( w, u, v );
mpi-genesis 228 v->sign = !v->sign;
mpi-genesis 229 }
mpi-genesis 230 }
mpi-genesis 231
mpi-genesis 232
mpi-genesis 233 void
mpi-genesis 234 mpi_addm( MPI w, MPI u, MPI v, MPI m)
mpi-genesis 235 {
mpi-genesis 236 mpi_add(w, u, v);
mpi-genesis 237 mpi_fdiv_r( w, w, m );
mpi-genesis 238 }
mpi-genesis 239
mpi-genesis 240 void
mpi-genesis 241 mpi_subm( MPI w, MPI u, MPI v, MPI m)
mpi-genesis 242 {
mpi-genesis 243 mpi_sub(w, u, v);
mpi-genesis 244 mpi_fdiv_r( w, w, m );
mpi-genesis 245 }
mpi-genesis 246