-/* crypto/bn/bn_add.c */
-/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
- * All rights reserved.
+/*
+ * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
*
- * This package is an SSL implementation written
- * by Eric Young (eay@cryptsoft.com).
- * The implementation was written so as to conform with Netscapes SSL.
- *
- * This library is free for commercial and non-commercial use as long as
- * the following conditions are aheared to. The following conditions
- * apply to all code found in this distribution, be it the RC4, RSA,
- * lhash, DES, etc., code; not just the SSL code. The SSL documentation
- * included with this distribution is covered by the same copyright terms
- * except that the holder is Tim Hudson (tjh@cryptsoft.com).
- *
- * Copyright remains Eric Young's, and as such any Copyright notices in
- * the code are not to be removed.
- * If this package is used in a product, Eric Young should be given attribution
- * as the author of the parts of the library used.
- * This can be in the form of a textual message at program startup or
- * in documentation (online or textual) provided with the package.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * "This product includes cryptographic software written by
- * Eric Young (eay@cryptsoft.com)"
- * The word 'cryptographic' can be left out if the rouines from the library
- * being used are not cryptographic related :-).
- * 4. If you include any Windows specific code (or a derivative thereof) from
- * the apps directory (application code) you must include an acknowledgement:
- * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
- *
- * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * The licence and distribution terms for any publically available version or
- * derivative of this code cannot be changed. i.e. this code cannot simply be
- * copied and put under another distribution licence
- * [including the GNU Public Licence.]
+ * Licensed under the Apache License 2.0 (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*/
-#include <stdio.h>
-#include "cryptlib.h"
+#include "internal/cryptlib.h"
#include "bn_lcl.h"
-/* r can == a or b */
-int BN_add(r, a, b)
-BIGNUM *r;
-BIGNUM *a;
-BIGNUM *b;
- {
- int i;
- BIGNUM *tmp;
-
- /* a + b a+b
- * a + -b a-b
- * -a + b b-a
- * -a + -b -(a+b)
- */
- if (a->neg ^ b->neg)
- {
- /* only one is negative */
- if (a->neg)
- { tmp=a; a=b; b=tmp; }
-
- /* we are now a - b */
- if (bn_expand(r,((a->top > b->top)?a->top:b->top)*BN_BITS2)
- == NULL) return(0);
-
- if (BN_ucmp(a,b) < 0)
- {
- bn_qsub(r,b,a);
- r->neg=1;
- }
- else
- {
- bn_qsub(r,a,b);
- r->neg=0;
- }
- return(1);
- }
-
- if (a->neg) /* both are neg */
- r->neg=1;
- else
- r->neg=0;
-
- i=(a->top > b->top);
- if (bn_expand(r,(((i)?a->top:b->top)+1)*BN_BITS2) == NULL) return(0);
-
- if (i)
- bn_qadd(r,a,b);
- else
- bn_qadd(r,b,a);
- return(1);
- }
-
-/* unsigned add of b to a, r must be large enough */
-void bn_qadd(r,a,b)
-BIGNUM *r;
-BIGNUM *a;
-BIGNUM *b;
- {
- register int i;
- int max,min;
- BN_ULONG *ap,*bp,*rp,carry,t1,t2;
-
- max=a->top;
- min=b->top;
- r->top=max;
-
- ap=a->d;
- bp=b->d;
- rp=r->d;
- carry=0;
- for (i=0; i<min; i++)
- {
- t1= *(ap++);
- t2= *(bp++);
- if (carry)
- {
- carry=(t2 >= ((~t1)&BN_MASK2));
- t2=(t1+t2+1)&BN_MASK2;
- }
- else
- {
- t2=(t1+t2)&BN_MASK2;
- carry=(t2 < t1);
- }
- *(rp++)=t2;
- }
- if (carry)
- {
- while (i < max)
- {
- t1= *(ap++);
- t2=(t1+1)&BN_MASK2;
- *(rp++)=t2;
- carry=(t2 < t1);
- i++;
- if (!carry) break;
- }
- if ((i >= max) && carry)
- {
- *(rp++)=1;
- r->top++;
- }
- }
- for (; i<max; i++)
- *(rp++)= *(ap++);
- /* memcpy(rp,ap,sizeof(*ap)*(max-i));*/
- }
+/* signed add of b to a. */
+int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
+{
+ int ret, r_neg, cmp_res;
+
+ bn_check_top(a);
+ bn_check_top(b);
+
+ if (a->neg == b->neg) {
+ r_neg = a->neg;
+ ret = BN_uadd(r, a, b);
+ } else {
+ cmp_res = BN_ucmp(a, b);
+ if (cmp_res > 0) {
+ r_neg = a->neg;
+ ret = BN_usub(r, a, b);
+ } else if (cmp_res < 0) {
+ r_neg = b->neg;
+ ret = BN_usub(r, b, a);
+ } else {
+ r_neg = 0;
+ BN_zero(r);
+ ret = 1;
+ }
+ }
+
+ r->neg = r_neg;
+ bn_check_top(r);
+ return ret;
+}
+
+/* signed sub of b from a. */
+int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
+{
+ int ret, r_neg, cmp_res;
+
+ bn_check_top(a);
+ bn_check_top(b);
+
+ if (a->neg != b->neg) {
+ r_neg = a->neg;
+ ret = BN_uadd(r, a, b);
+ } else {
+ cmp_res = BN_ucmp(a, b);
+ if (cmp_res > 0) {
+ r_neg = a->neg;
+ ret = BN_usub(r, a, b);
+ } else if (cmp_res < 0) {
+ r_neg = !b->neg;
+ ret = BN_usub(r, b, a);
+ } else {
+ r_neg = 0;
+ BN_zero(r);
+ ret = 1;
+ }
+ }
+
+ r->neg = r_neg;
+ bn_check_top(r);
+ return ret;
+}
+
+/* unsigned add of b to a, r can be equal to a or b. */
+int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
+{
+ int max, min, dif;
+ const BN_ULONG *ap, *bp;
+ BN_ULONG *rp, carry, t1, t2;
+
+ bn_check_top(a);
+ bn_check_top(b);
+
+ if (a->top < b->top) {
+ const BIGNUM *tmp;
+
+ tmp = a;
+ a = b;
+ b = tmp;
+ }
+ max = a->top;
+ min = b->top;
+ dif = max - min;
+
+ if (bn_wexpand(r, max + 1) == NULL)
+ return 0;
+
+ r->top = max;
+
+ ap = a->d;
+ bp = b->d;
+ rp = r->d;
+
+ carry = bn_add_words(rp, ap, bp, min);
+ rp += min;
+ ap += min;
+
+ while (dif) {
+ dif--;
+ t1 = *(ap++);
+ t2 = (t1 + carry) & BN_MASK2;
+ *(rp++) = t2;
+ carry &= (t2 == 0);
+ }
+ *rp = carry;
+ r->top += carry;
+
+ r->neg = 0;
+ bn_check_top(r);
+ return 1;
+}
+
+/* unsigned subtraction of b from a, a must be larger than b. */
+int BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
+{
+ int max, min, dif;
+ BN_ULONG t1, t2, borrow, *rp;
+ const BN_ULONG *ap, *bp;
+
+ bn_check_top(a);
+ bn_check_top(b);
+
+ max = a->top;
+ min = b->top;
+ dif = max - min;
+
+ if (dif < 0) { /* hmm... should not be happening */
+ BNerr(BN_F_BN_USUB, BN_R_ARG2_LT_ARG3);
+ return 0;
+ }
+
+ if (bn_wexpand(r, max) == NULL)
+ return 0;
+
+ ap = a->d;
+ bp = b->d;
+ rp = r->d;
+
+ borrow = bn_sub_words(rp, ap, bp, min);
+ ap += min;
+ rp += min;
+
+ while (dif) {
+ dif--;
+ t1 = *(ap++);
+ t2 = (t1 - borrow) & BN_MASK2;
+ *(rp++) = t2;
+ borrow &= (t1 == 0);
+ }
+
+ while (max && *--rp == 0)
+ max--;
+
+ r->top = max;
+ r->neg = 0;
+ bn_pollute(r);
+
+ return 1;
+}
projects / openssl.git / blobdiff