mirror of
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517 lines
14 KiB
C
517 lines
14 KiB
C
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/*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the elliptic curve math library for prime field curves.
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*
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* The Initial Developer of the Original Code is
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* Sun Microsystems, Inc.
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* Portions created by the Initial Developer are Copyright (C) 2003
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Douglas Stebila <douglas@stebila.ca>, Sun Microsystems Laboratories
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#include "ecp.h"
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#include "mpi.h"
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#include "mplogic.h"
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#include "mpi-priv.h"
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#include <stdlib.h>
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#define ECP192_DIGITS ECL_CURVE_DIGITS(192)
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/* Fast modular reduction for p192 = 2^192 - 2^64 - 1. a can be r. Uses
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* algorithm 7 from Brown, Hankerson, Lopez, Menezes. Software
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* Implementation of the NIST Elliptic Curves over Prime Fields. */
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mp_err
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ec_GFp_nistp192_mod(const mp_int *a, mp_int *r, const GFMethod *meth)
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{
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mp_err res = MP_OKAY;
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mp_size a_used = MP_USED(a);
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mp_digit r3;
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#ifndef MPI_AMD64_ADD
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mp_digit carry;
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#endif
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#ifdef ECL_THIRTY_TWO_BIT
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mp_digit a5a = 0, a5b = 0, a4a = 0, a4b = 0, a3a = 0, a3b = 0;
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mp_digit r0a, r0b, r1a, r1b, r2a, r2b;
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#else
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mp_digit a5 = 0, a4 = 0, a3 = 0;
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mp_digit r0, r1, r2;
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#endif
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/* reduction not needed if a is not larger than field size */
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if (a_used < ECP192_DIGITS) {
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if (a == r) {
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return MP_OKAY;
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}
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return mp_copy(a, r);
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}
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/* for polynomials larger than twice the field size, use regular
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* reduction */
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if (a_used > ECP192_DIGITS*2) {
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MP_CHECKOK(mp_mod(a, &meth->irr, r));
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} else {
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/* copy out upper words of a */
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#ifdef ECL_THIRTY_TWO_BIT
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/* in all the math below,
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* nXb is most signifiant, nXa is least significant */
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switch (a_used) {
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case 12:
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a5b = MP_DIGIT(a, 11);
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case 11:
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a5a = MP_DIGIT(a, 10);
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case 10:
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a4b = MP_DIGIT(a, 9);
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case 9:
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a4a = MP_DIGIT(a, 8);
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case 8:
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a3b = MP_DIGIT(a, 7);
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case 7:
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a3a = MP_DIGIT(a, 6);
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}
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r2b= MP_DIGIT(a, 5);
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r2a= MP_DIGIT(a, 4);
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r1b = MP_DIGIT(a, 3);
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r1a = MP_DIGIT(a, 2);
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r0b = MP_DIGIT(a, 1);
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r0a = MP_DIGIT(a, 0);
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/* implement r = (a2,a1,a0)+(a5,a5,a5)+(a4,a4,0)+(0,a3,a3) */
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MP_ADD_CARRY(r0a, a3a, r0a, 0, carry);
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MP_ADD_CARRY(r0b, a3b, r0b, carry, carry);
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MP_ADD_CARRY(r1a, a3a, r1a, carry, carry);
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MP_ADD_CARRY(r1b, a3b, r1b, carry, carry);
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MP_ADD_CARRY(r2a, a4a, r2a, carry, carry);
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MP_ADD_CARRY(r2b, a4b, r2b, carry, carry);
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r3 = carry; carry = 0;
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MP_ADD_CARRY(r0a, a5a, r0a, 0, carry);
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MP_ADD_CARRY(r0b, a5b, r0b, carry, carry);
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MP_ADD_CARRY(r1a, a5a, r1a, carry, carry);
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MP_ADD_CARRY(r1b, a5b, r1b, carry, carry);
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MP_ADD_CARRY(r2a, a5a, r2a, carry, carry);
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MP_ADD_CARRY(r2b, a5b, r2b, carry, carry);
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r3 += carry;
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MP_ADD_CARRY(r1a, a4a, r1a, 0, carry);
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MP_ADD_CARRY(r1b, a4b, r1b, carry, carry);
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MP_ADD_CARRY(r2a, 0, r2a, carry, carry);
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MP_ADD_CARRY(r2b, 0, r2b, carry, carry);
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r3 += carry;
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/* reduce out the carry */
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while (r3) {
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MP_ADD_CARRY(r0a, r3, r0a, 0, carry);
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MP_ADD_CARRY(r0b, 0, r0b, carry, carry);
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MP_ADD_CARRY(r1a, r3, r1a, carry, carry);
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MP_ADD_CARRY(r1b, 0, r1b, carry, carry);
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MP_ADD_CARRY(r2a, 0, r2a, carry, carry);
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MP_ADD_CARRY(r2b, 0, r2b, carry, carry);
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r3 = carry;
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}
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/* check for final reduction */
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/*
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* our field is 0xffffffffffffffff, 0xfffffffffffffffe,
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* 0xffffffffffffffff. That means we can only be over and need
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* one more reduction
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* if r2 == 0xffffffffffffffffff (same as r2+1 == 0)
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* and
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* r1 == 0xffffffffffffffffff or
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* r1 == 0xfffffffffffffffffe and r0 = 0xfffffffffffffffff
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* In all cases, we subtract the field (or add the 2's
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* complement value (1,1,0)). (r0, r1, r2)
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*/
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if (((r2b == 0xffffffff) && (r2a == 0xffffffff)
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&& (r1b == 0xffffffff) ) &&
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((r1a == 0xffffffff) ||
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(r1a == 0xfffffffe) && (r0a == 0xffffffff) &&
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(r0b == 0xffffffff)) ) {
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/* do a quick subtract */
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MP_ADD_CARRY(r0a, 1, r0a, 0, carry);
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r0b += carry;
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r1a = r1b = r2a = r2b = 0;
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}
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/* set the lower words of r */
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if (a != r) {
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MP_CHECKOK(s_mp_pad(r, 6));
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}
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MP_DIGIT(r, 5) = r2b;
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MP_DIGIT(r, 4) = r2a;
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MP_DIGIT(r, 3) = r1b;
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MP_DIGIT(r, 2) = r1a;
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MP_DIGIT(r, 1) = r0b;
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MP_DIGIT(r, 0) = r0a;
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MP_USED(r) = 6;
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#else
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switch (a_used) {
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case 6:
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a5 = MP_DIGIT(a, 5);
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case 5:
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a4 = MP_DIGIT(a, 4);
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case 4:
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a3 = MP_DIGIT(a, 3);
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}
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r2 = MP_DIGIT(a, 2);
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r1 = MP_DIGIT(a, 1);
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r0 = MP_DIGIT(a, 0);
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/* implement r = (a2,a1,a0)+(a5,a5,a5)+(a4,a4,0)+(0,a3,a3) */
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#ifndef MPI_AMD64_ADD
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MP_ADD_CARRY(r0, a3, r0, 0, carry);
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MP_ADD_CARRY(r1, a3, r1, carry, carry);
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MP_ADD_CARRY(r2, a4, r2, carry, carry);
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r3 = carry;
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MP_ADD_CARRY(r0, a5, r0, 0, carry);
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MP_ADD_CARRY(r1, a5, r1, carry, carry);
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MP_ADD_CARRY(r2, a5, r2, carry, carry);
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r3 += carry;
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MP_ADD_CARRY(r1, a4, r1, 0, carry);
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MP_ADD_CARRY(r2, 0, r2, carry, carry);
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r3 += carry;
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#else
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r2 = MP_DIGIT(a, 2);
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r1 = MP_DIGIT(a, 1);
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r0 = MP_DIGIT(a, 0);
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/* set the lower words of r */
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__asm__ (
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"xorq %3,%3 \n\t"
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"addq %4,%0 \n\t"
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"adcq %4,%1 \n\t"
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"adcq %5,%2 \n\t"
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"adcq $0,%3 \n\t"
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"addq %6,%0 \n\t"
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"adcq %6,%1 \n\t"
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"adcq %6,%2 \n\t"
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"adcq $0,%3 \n\t"
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"addq %5,%1 \n\t"
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"adcq $0,%2 \n\t"
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"adcq $0,%3 \n\t"
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: "=r"(r0), "=r"(r1), "=r"(r2), "=r"(r3), "=r"(a3),
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"=r"(a4), "=r"(a5)
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: "0" (r0), "1" (r1), "2" (r2), "3" (r3),
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"4" (a3), "5" (a4), "6"(a5)
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: "%cc" );
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#endif
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/* reduce out the carry */
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while (r3) {
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#ifndef MPI_AMD64_ADD
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MP_ADD_CARRY(r0, r3, r0, 0, carry);
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MP_ADD_CARRY(r1, r3, r1, carry, carry);
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MP_ADD_CARRY(r2, 0, r2, carry, carry);
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r3 = carry;
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#else
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a3=r3;
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__asm__ (
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"xorq %3,%3 \n\t"
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"addq %4,%0 \n\t"
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"adcq %4,%1 \n\t"
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"adcq $0,%2 \n\t"
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"adcq $0,%3 \n\t"
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: "=r"(r0), "=r"(r1), "=r"(r2), "=r"(r3), "=r"(a3)
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: "0" (r0), "1" (r1), "2" (r2), "3" (r3), "4"(a3)
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: "%cc" );
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#endif
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}
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/* check for final reduction */
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/*
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* our field is 0xffffffffffffffff, 0xfffffffffffffffe,
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* 0xffffffffffffffff. That means we can only be over and need
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* one more reduction
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* if r2 == 0xffffffffffffffffff (same as r2+1 == 0)
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* and
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* r1 == 0xffffffffffffffffff or
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* r1 == 0xfffffffffffffffffe and r0 = 0xfffffffffffffffff
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* In all cases, we subtract the field (or add the 2's
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* complement value (1,1,0)). (r0, r1, r2)
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*/
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if (r3 || ((r2 == MP_DIGIT_MAX) &&
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((r1 == MP_DIGIT_MAX) ||
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((r1 == (MP_DIGIT_MAX-1)) && (r0 == MP_DIGIT_MAX))))) {
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/* do a quick subtract */
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r0++;
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r1 = r2 = 0;
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}
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/* set the lower words of r */
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if (a != r) {
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MP_CHECKOK(s_mp_pad(r, 3));
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}
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MP_DIGIT(r, 2) = r2;
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MP_DIGIT(r, 1) = r1;
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MP_DIGIT(r, 0) = r0;
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MP_USED(r) = 3;
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#endif
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}
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CLEANUP:
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return res;
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}
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#ifndef ECL_THIRTY_TWO_BIT
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/* Compute the sum of 192 bit curves. Do the work in-line since the
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* number of words are so small, we don't want to overhead of mp function
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* calls. Uses optimized modular reduction for p192.
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*/
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mp_err
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ec_GFp_nistp192_add(const mp_int *a, const mp_int *b, mp_int *r,
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const GFMethod *meth)
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{
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mp_err res = MP_OKAY;
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mp_digit a0 = 0, a1 = 0, a2 = 0;
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mp_digit r0 = 0, r1 = 0, r2 = 0;
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mp_digit carry;
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switch(MP_USED(a)) {
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case 3:
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a2 = MP_DIGIT(a,2);
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case 2:
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a1 = MP_DIGIT(a,1);
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case 1:
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a0 = MP_DIGIT(a,0);
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}
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switch(MP_USED(b)) {
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case 3:
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r2 = MP_DIGIT(b,2);
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case 2:
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r1 = MP_DIGIT(b,1);
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case 1:
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r0 = MP_DIGIT(b,0);
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}
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#ifndef MPI_AMD64_ADD
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MP_ADD_CARRY(a0, r0, r0, 0, carry);
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MP_ADD_CARRY(a1, r1, r1, carry, carry);
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MP_ADD_CARRY(a2, r2, r2, carry, carry);
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#else
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__asm__ (
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"xorq %3,%3 \n\t"
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"addq %4,%0 \n\t"
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"adcq %5,%1 \n\t"
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"adcq %6,%2 \n\t"
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"adcq $0,%3 \n\t"
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: "=r"(r0), "=r"(r1), "=r"(r2), "=r"(carry)
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: "r" (a0), "r" (a1), "r" (a2), "0" (r0),
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"1" (r1), "2" (r2)
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: "%cc" );
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#endif
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/* Do quick 'subract' if we've gone over
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* (add the 2's complement of the curve field) */
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if (carry || ((r2 == MP_DIGIT_MAX) &&
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((r1 == MP_DIGIT_MAX) ||
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((r1 == (MP_DIGIT_MAX-1)) && (r0 == MP_DIGIT_MAX))))) {
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#ifndef MPI_AMD64_ADD
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MP_ADD_CARRY(r0, 1, r0, 0, carry);
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MP_ADD_CARRY(r1, 1, r1, carry, carry);
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MP_ADD_CARRY(r2, 0, r2, carry, carry);
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#else
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__asm__ (
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"addq $1,%0 \n\t"
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"adcq $1,%1 \n\t"
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"adcq $0,%2 \n\t"
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: "=r"(r0), "=r"(r1), "=r"(r2)
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: "0" (r0), "1" (r1), "2" (r2)
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: "%cc" );
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#endif
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}
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MP_CHECKOK(s_mp_pad(r, 3));
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MP_DIGIT(r, 2) = r2;
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MP_DIGIT(r, 1) = r1;
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MP_DIGIT(r, 0) = r0;
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MP_SIGN(r) = MP_ZPOS;
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MP_USED(r) = 3;
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s_mp_clamp(r);
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CLEANUP:
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return res;
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}
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/* Compute the diff of 192 bit curves. Do the work in-line since the
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* number of words are so small, we don't want to overhead of mp function
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* calls. Uses optimized modular reduction for p192.
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*/
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mp_err
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ec_GFp_nistp192_sub(const mp_int *a, const mp_int *b, mp_int *r,
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const GFMethod *meth)
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{
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||
|
mp_err res = MP_OKAY;
|
||
|
mp_digit b0 = 0, b1 = 0, b2 = 0;
|
||
|
mp_digit r0 = 0, r1 = 0, r2 = 0;
|
||
|
mp_digit borrow;
|
||
|
|
||
|
switch(MP_USED(a)) {
|
||
|
case 3:
|
||
|
r2 = MP_DIGIT(a,2);
|
||
|
case 2:
|
||
|
r1 = MP_DIGIT(a,1);
|
||
|
case 1:
|
||
|
r0 = MP_DIGIT(a,0);
|
||
|
}
|
||
|
|
||
|
switch(MP_USED(b)) {
|
||
|
case 3:
|
||
|
b2 = MP_DIGIT(b,2);
|
||
|
case 2:
|
||
|
b1 = MP_DIGIT(b,1);
|
||
|
case 1:
|
||
|
b0 = MP_DIGIT(b,0);
|
||
|
}
|
||
|
|
||
|
#ifndef MPI_AMD64_ADD
|
||
|
MP_SUB_BORROW(r0, b0, r0, 0, borrow);
|
||
|
MP_SUB_BORROW(r1, b1, r1, borrow, borrow);
|
||
|
MP_SUB_BORROW(r2, b2, r2, borrow, borrow);
|
||
|
#else
|
||
|
__asm__ (
|
||
|
"xorq %3,%3 \n\t"
|
||
|
"subq %4,%0 \n\t"
|
||
|
"sbbq %5,%1 \n\t"
|
||
|
"sbbq %6,%2 \n\t"
|
||
|
"adcq $0,%3 \n\t"
|
||
|
: "=r"(r0), "=r"(r1), "=r"(r2), "=r"(borrow)
|
||
|
: "r" (b0), "r" (b1), "r" (b2), "0" (r0),
|
||
|
"1" (r1), "2" (r2)
|
||
|
: "%cc" );
|
||
|
#endif
|
||
|
|
||
|
/* Do quick 'add' if we've gone under 0
|
||
|
* (subtract the 2's complement of the curve field) */
|
||
|
if (borrow) {
|
||
|
#ifndef MPI_AMD64_ADD
|
||
|
MP_SUB_BORROW(r0, 1, r0, 0, borrow);
|
||
|
MP_SUB_BORROW(r1, 1, r1, borrow, borrow);
|
||
|
MP_SUB_BORROW(r2, 0, r2, borrow, borrow);
|
||
|
#else
|
||
|
__asm__ (
|
||
|
"subq $1,%0 \n\t"
|
||
|
"sbbq $1,%1 \n\t"
|
||
|
"sbbq $0,%2 \n\t"
|
||
|
: "=r"(r0), "=r"(r1), "=r"(r2)
|
||
|
: "0" (r0), "1" (r1), "2" (r2)
|
||
|
: "%cc" );
|
||
|
#endif
|
||
|
}
|
||
|
|
||
|
MP_CHECKOK(s_mp_pad(r, 3));
|
||
|
MP_DIGIT(r, 2) = r2;
|
||
|
MP_DIGIT(r, 1) = r1;
|
||
|
MP_DIGIT(r, 0) = r0;
|
||
|
MP_SIGN(r) = MP_ZPOS;
|
||
|
MP_USED(r) = 3;
|
||
|
s_mp_clamp(r);
|
||
|
|
||
|
CLEANUP:
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
#endif
|
||
|
|
||
|
/* Compute the square of polynomial a, reduce modulo p192. Store the
|
||
|
* result in r. r could be a. Uses optimized modular reduction for p192.
|
||
|
*/
|
||
|
mp_err
|
||
|
ec_GFp_nistp192_sqr(const mp_int *a, mp_int *r, const GFMethod *meth)
|
||
|
{
|
||
|
mp_err res = MP_OKAY;
|
||
|
|
||
|
MP_CHECKOK(mp_sqr(a, r));
|
||
|
MP_CHECKOK(ec_GFp_nistp192_mod(r, r, meth));
|
||
|
CLEANUP:
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
/* Compute the product of two polynomials a and b, reduce modulo p192.
|
||
|
* Store the result in r. r could be a or b; a could be b. Uses
|
||
|
* optimized modular reduction for p192. */
|
||
|
mp_err
|
||
|
ec_GFp_nistp192_mul(const mp_int *a, const mp_int *b, mp_int *r,
|
||
|
const GFMethod *meth)
|
||
|
{
|
||
|
mp_err res = MP_OKAY;
|
||
|
|
||
|
MP_CHECKOK(mp_mul(a, b, r));
|
||
|
MP_CHECKOK(ec_GFp_nistp192_mod(r, r, meth));
|
||
|
CLEANUP:
|
||
|
return res;
|
||
|
}
|
||
|
|
||
|
/* Divides two field elements. If a is NULL, then returns the inverse of
|
||
|
* b. */
|
||
|
mp_err
|
||
|
ec_GFp_nistp192_div(const mp_int *a, const mp_int *b, mp_int *r,
|
||
|
const GFMethod *meth)
|
||
|
{
|
||
|
mp_err res = MP_OKAY;
|
||
|
mp_int t;
|
||
|
|
||
|
/* If a is NULL, then return the inverse of b, otherwise return a/b. */
|
||
|
if (a == NULL) {
|
||
|
return mp_invmod(b, &meth->irr, r);
|
||
|
} else {
|
||
|
/* MPI doesn't support divmod, so we implement it using invmod and
|
||
|
* mulmod. */
|
||
|
MP_CHECKOK(mp_init(&t));
|
||
|
MP_CHECKOK(mp_invmod(b, &meth->irr, &t));
|
||
|
MP_CHECKOK(mp_mul(a, &t, r));
|
||
|
MP_CHECKOK(ec_GFp_nistp192_mod(r, r, meth));
|
||
|
CLEANUP:
|
||
|
mp_clear(&t);
|
||
|
return res;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* Wire in fast field arithmetic and precomputation of base point for
|
||
|
* named curves. */
|
||
|
mp_err
|
||
|
ec_group_set_gfp192(ECGroup *group, ECCurveName name)
|
||
|
{
|
||
|
if (name == ECCurve_NIST_P192) {
|
||
|
group->meth->field_mod = &ec_GFp_nistp192_mod;
|
||
|
group->meth->field_mul = &ec_GFp_nistp192_mul;
|
||
|
group->meth->field_sqr = &ec_GFp_nistp192_sqr;
|
||
|
group->meth->field_div = &ec_GFp_nistp192_div;
|
||
|
#ifndef ECL_THIRTY_TWO_BIT
|
||
|
group->meth->field_add = &ec_GFp_nistp192_add;
|
||
|
group->meth->field_sub = &ec_GFp_nistp192_sub;
|
||
|
#endif
|
||
|
}
|
||
|
return MP_OKAY;
|
||
|
}
|