2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #include "internal/cryptlib.h"
13 int BN_lshift1(BIGNUM *r, const BIGNUM *a)
15 register BN_ULONG *ap, *rp, t, c;
23 if (bn_wexpand(r, a->top + 1) == NULL)
27 if (bn_wexpand(r, a->top + 1) == NULL)
33 for (i = 0; i < a->top; i++) {
35 *(rp++) = ((t << 1) | c) & BN_MASK2;
36 c = (t & BN_TBIT) ? 1 : 0;
46 int BN_rshift1(BIGNUM *r, const BIGNUM *a)
48 BN_ULONG *ap, *rp, t, c;
60 j = i - (ap[i - 1] == 1);
62 if (bn_wexpand(r, j) == NULL)
68 c = (t & 1) ? BN_TBIT : 0;
73 rp[i] = ((t >> 1) & BN_MASK2) | c;
74 c = (t & 1) ? BN_TBIT : 0;
78 r->neg = 0; /* don't allow negative zero */
83 int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
93 BNerr(BN_F_BN_LSHIFT, BN_R_INVALID_SHIFT);
98 if (bn_wexpand(r, a->top + nw + 1) == NULL)
107 for (i = a->top - 1; i >= 0; i--)
110 for (i = a->top - 1; i >= 0; i--) {
112 t[nw + i + 1] |= (l >> rb) & BN_MASK2;
113 t[nw + i] = (l << lb) & BN_MASK2;
115 memset(t, 0, sizeof(*t) * nw);
116 r->top = a->top + nw + 1;
122 int BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
124 int i, j, nw, lb, rb;
132 BNerr(BN_F_BN_RSHIFT, BN_R_INVALID_SHIFT);
139 if (nw >= a->top || a->top == 0) {
143 i = (BN_num_bits(a) - n + (BN_BITS2 - 1)) / BN_BITS2;
145 if (bn_wexpand(r, i) == NULL)
150 return 1; /* or the copying loop will go berserk */
159 for (i = j; i != 0; i--)
163 for (i = j - 1; i != 0; i--) {
164 tmp = (l >> rb) & BN_MASK2;
166 *(t++) = (tmp | (l << lb)) & BN_MASK2;
168 if ((l = (l >> rb) & BN_MASK2))
172 r->neg = 0; /* don't allow negative zero */