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Diffstat (limited to 'src/crypto/bn/mul.c')
-rw-r--r-- | src/crypto/bn/mul.c | 886 |
1 files changed, 886 insertions, 0 deletions
diff --git a/src/crypto/bn/mul.c b/src/crypto/bn/mul.c new file mode 100644 index 0000000..80c6288 --- /dev/null +++ b/src/crypto/bn/mul.c @@ -0,0 +1,886 @@ +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) + * 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.] */ + +#include <openssl/bn.h> + +#include <assert.h> +#include <string.h> + +#include "internal.h" + + +void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb) { + BN_ULONG *rr; + + if (na < nb) { + int itmp; + BN_ULONG *ltmp; + + itmp = na; + na = nb; + nb = itmp; + ltmp = a; + a = b; + b = ltmp; + } + rr = &(r[na]); + if (nb <= 0) { + (void)bn_mul_words(r, a, na, 0); + return; + } else { + rr[0] = bn_mul_words(r, a, na, b[0]); + } + + for (;;) { + if (--nb <= 0) { + return; + } + rr[1] = bn_mul_add_words(&(r[1]), a, na, b[1]); + if (--nb <= 0) { + return; + } + rr[2] = bn_mul_add_words(&(r[2]), a, na, b[2]); + if (--nb <= 0) { + return; + } + rr[3] = bn_mul_add_words(&(r[3]), a, na, b[3]); + if (--nb <= 0) { + return; + } + rr[4] = bn_mul_add_words(&(r[4]), a, na, b[4]); + rr += 4; + r += 4; + b += 4; + } +} + +void bn_mul_low_normal(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n) { + bn_mul_words(r, a, n, b[0]); + + for (;;) { + if (--n <= 0) { + return; + } + bn_mul_add_words(&(r[1]), a, n, b[1]); + if (--n <= 0) { + return; + } + bn_mul_add_words(&(r[2]), a, n, b[2]); + if (--n <= 0) { + return; + } + bn_mul_add_words(&(r[3]), a, n, b[3]); + if (--n <= 0) { + return; + } + bn_mul_add_words(&(r[4]), a, n, b[4]); + r += 4; + b += 4; + } +} + +#if !defined(OPENSSL_X86) || defined(OPENSSL_NO_ASM) +/* Here follows specialised variants of bn_add_words() and bn_sub_words(). They + * have the property performing operations on arrays of different sizes. The + * sizes of those arrays is expressed through cl, which is the common length ( + * basicall, min(len(a),len(b)) ), and dl, which is the delta between the two + * lengths, calculated as len(a)-len(b). All lengths are the number of + * BN_ULONGs... For the operations that require a result array as parameter, + * it must have the length cl+abs(dl). These functions should probably end up + * in bn_asm.c as soon as there are assembler counterparts for the systems that + * use assembler files. */ + +static BN_ULONG bn_sub_part_words(BN_ULONG *r, const BN_ULONG *a, + const BN_ULONG *b, int cl, int dl) { + BN_ULONG c, t; + + assert(cl >= 0); + c = bn_sub_words(r, a, b, cl); + + if (dl == 0) + return c; + + r += cl; + a += cl; + b += cl; + + if (dl < 0) { + for (;;) { + t = b[0]; + r[0] = (0 - t - c) & BN_MASK2; + if (t != 0) { + c = 1; + } + if (++dl >= 0) { + break; + } + + t = b[1]; + r[1] = (0 - t - c) & BN_MASK2; + if (t != 0) { + c = 1; + } + if (++dl >= 0) { + break; + } + + t = b[2]; + r[2] = (0 - t - c) & BN_MASK2; + if (t != 0) { + c = 1; + } + if (++dl >= 0) { + break; + } + + t = b[3]; + r[3] = (0 - t - c) & BN_MASK2; + if (t != 0) { + c = 1; + } + if (++dl >= 0) { + break; + } + + b += 4; + r += 4; + } + } else { + int save_dl = dl; + while (c) { + t = a[0]; + r[0] = (t - c) & BN_MASK2; + if (t != 0) { + c = 0; + } + if (--dl <= 0) { + break; + } + + t = a[1]; + r[1] = (t - c) & BN_MASK2; + if (t != 0) { + c = 0; + } + if (--dl <= 0) { + break; + } + + t = a[2]; + r[2] = (t - c) & BN_MASK2; + if (t != 0) { + c = 0; + } + if (--dl <= 0) { + break; + } + + t = a[3]; + r[3] = (t - c) & BN_MASK2; + if (t != 0) { + c = 0; + } + if (--dl <= 0) { + break; + } + + save_dl = dl; + a += 4; + r += 4; + } + if (dl > 0) { + if (save_dl > dl) { + switch (save_dl - dl) { + case 1: + r[1] = a[1]; + if (--dl <= 0) { + break; + } + case 2: + r[2] = a[2]; + if (--dl <= 0) { + break; + } + case 3: + r[3] = a[3]; + if (--dl <= 0) { + break; + } + } + a += 4; + r += 4; + } + } + + if (dl > 0) { + for (;;) { + r[0] = a[0]; + if (--dl <= 0) { + break; + } + r[1] = a[1]; + if (--dl <= 0) { + break; + } + r[2] = a[2]; + if (--dl <= 0) { + break; + } + r[3] = a[3]; + if (--dl <= 0) { + break; + } + + a += 4; + r += 4; + } + } + } + + return c; +} +#else +/* On other platforms the function is defined in asm. */ +BN_ULONG bn_sub_part_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b, + int cl, int dl); +#endif + +/* Karatsuba recursive multiplication algorithm + * (cf. Knuth, The Art of Computer Programming, Vol. 2) */ + +/* r is 2*n2 words in size, + * a and b are both n2 words in size. + * n2 must be a power of 2. + * We multiply and return the result. + * t must be 2*n2 words in size + * We calculate + * a[0]*b[0] + * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0]) + * a[1]*b[1] + */ +/* dnX may not be positive, but n2/2+dnX has to be */ +static void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2, + int dna, int dnb, BN_ULONG *t) { + int n = n2 / 2, c1, c2; + int tna = n + dna, tnb = n + dnb; + unsigned int neg, zero; + BN_ULONG ln, lo, *p; + + /* Only call bn_mul_comba 8 if n2 == 8 and the + * two arrays are complete [steve] + */ + if (n2 == 8 && dna == 0 && dnb == 0) { + bn_mul_comba8(r, a, b); + return; + } + + /* Else do normal multiply */ + if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL) { + bn_mul_normal(r, a, n2 + dna, b, n2 + dnb); + if ((dna + dnb) < 0) + memset(&r[2 * n2 + dna + dnb], 0, sizeof(BN_ULONG) * -(dna + dnb)); + return; + } + + /* r=(a[0]-a[1])*(b[1]-b[0]) */ + c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna); + c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n); + zero = neg = 0; + switch (c1 * 3 + c2) { + case -4: + bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */ + bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */ + break; + case -3: + zero = 1; + break; + case -2: + bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */ + bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); /* + */ + neg = 1; + break; + case -1: + case 0: + case 1: + zero = 1; + break; + case 2: + bn_sub_part_words(t, a, &(a[n]), tna, n - tna); /* + */ + bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */ + neg = 1; + break; + case 3: + zero = 1; + break; + case 4: + bn_sub_part_words(t, a, &(a[n]), tna, n - tna); + bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); + break; + } + + if (n == 4 && dna == 0 && dnb == 0) { + /* XXX: bn_mul_comba4 could take extra args to do this well */ + if (!zero) { + bn_mul_comba4(&(t[n2]), t, &(t[n])); + } else { + memset(&(t[n2]), 0, 8 * sizeof(BN_ULONG)); + } + + bn_mul_comba4(r, a, b); + bn_mul_comba4(&(r[n2]), &(a[n]), &(b[n])); + } else if (n == 8 && dna == 0 && dnb == 0) { + /* XXX: bn_mul_comba8 could take extra args to do this well */ + if (!zero) { + bn_mul_comba8(&(t[n2]), t, &(t[n])); + } else { + memset(&(t[n2]), 0, 16 * sizeof(BN_ULONG)); + } + + bn_mul_comba8(r, a, b); + bn_mul_comba8(&(r[n2]), &(a[n]), &(b[n])); + } else { + p = &(t[n2 * 2]); + if (!zero) { + bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p); + } else { + memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG)); + } + bn_mul_recursive(r, a, b, n, 0, 0, p); + bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), n, dna, dnb, p); + } + + /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign + * r[10] holds (a[0]*b[0]) + * r[32] holds (b[1]*b[1]) */ + + c1 = (int)(bn_add_words(t, r, &(r[n2]), n2)); + + if (neg) { + /* if t[32] is negative */ + c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2)); + } else { + /* Might have a carry */ + c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2)); + } + + /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1]) + * r[10] holds (a[0]*b[0]) + * r[32] holds (b[1]*b[1]) + * c1 holds the carry bits */ + c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2)); + if (c1) { + p = &(r[n + n2]); + lo = *p; + ln = (lo + c1) & BN_MASK2; + *p = ln; + + /* The overflow will stop before we over write + * words we should not overwrite */ + if (ln < (BN_ULONG)c1) { + do { + p++; + lo = *p; + ln = (lo + 1) & BN_MASK2; + *p = ln; + } while (ln == 0); + } + } +} + +/* n+tn is the word length + * t needs to be n*4 is size, as does r */ +/* tnX may not be negative but less than n */ +static void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n, + int tna, int tnb, BN_ULONG *t) { + int i, j, n2 = n * 2; + int c1, c2, neg; + BN_ULONG ln, lo, *p; + + if (n < 8) { + bn_mul_normal(r, a, n + tna, b, n + tnb); + return; + } + + /* r=(a[0]-a[1])*(b[1]-b[0]) */ + c1 = bn_cmp_part_words(a, &(a[n]), tna, n - tna); + c2 = bn_cmp_part_words(&(b[n]), b, tnb, tnb - n); + neg = 0; + switch (c1 * 3 + c2) { + case -4: + bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */ + bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */ + break; + case -3: + /* break; */ + case -2: + bn_sub_part_words(t, &(a[n]), a, tna, tna - n); /* - */ + bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); /* + */ + neg = 1; + break; + case -1: + case 0: + case 1: + /* break; */ + case 2: + bn_sub_part_words(t, a, &(a[n]), tna, n - tna); /* + */ + bn_sub_part_words(&(t[n]), b, &(b[n]), tnb, n - tnb); /* - */ + neg = 1; + break; + case 3: + /* break; */ + case 4: + bn_sub_part_words(t, a, &(a[n]), tna, n - tna); + bn_sub_part_words(&(t[n]), &(b[n]), b, tnb, tnb - n); + break; + } + + if (n == 8) { + bn_mul_comba8(&(t[n2]), t, &(t[n])); + bn_mul_comba8(r, a, b); + bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb); + memset(&(r[n2 + tna + tnb]), 0, sizeof(BN_ULONG) * (n2 - tna - tnb)); + } else { + p = &(t[n2 * 2]); + bn_mul_recursive(&(t[n2]), t, &(t[n]), n, 0, 0, p); + bn_mul_recursive(r, a, b, n, 0, 0, p); + i = n / 2; + /* If there is only a bottom half to the number, + * just do it */ + if (tna > tnb) { + j = tna - i; + } else { + j = tnb - i; + } + + if (j == 0) { + bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, tnb - i, p); + memset(&(r[n2 + i * 2]), 0, sizeof(BN_ULONG) * (n2 - i * 2)); + } else if (j > 0) { + /* eg, n == 16, i == 8 and tn == 11 */ + bn_mul_part_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, tnb - i, p); + memset(&(r[n2 + tna + tnb]), 0, sizeof(BN_ULONG) * (n2 - tna - tnb)); + } else { + /* (j < 0) eg, n == 16, i == 8 and tn == 5 */ + memset(&(r[n2]), 0, sizeof(BN_ULONG) * n2); + if (tna < BN_MUL_RECURSIVE_SIZE_NORMAL && + tnb < BN_MUL_RECURSIVE_SIZE_NORMAL) { + bn_mul_normal(&(r[n2]), &(a[n]), tna, &(b[n]), tnb); + } else { + for (;;) { + i /= 2; + /* these simplified conditions work + * exclusively because difference + * between tna and tnb is 1 or 0 */ + if (i < tna || i < tnb) { + bn_mul_part_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, + tnb - i, p); + break; + } else if (i == tna || i == tnb) { + bn_mul_recursive(&(r[n2]), &(a[n]), &(b[n]), i, tna - i, tnb - i, + p); + break; + } + } + } + } + } + + /* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign + * r[10] holds (a[0]*b[0]) + * r[32] holds (b[1]*b[1]) + */ + + c1 = (int)(bn_add_words(t, r, &(r[n2]), n2)); + + if (neg) { + /* if t[32] is negative */ + c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2)); + } else { + /* Might have a carry */ + c1 += (int)(bn_add_words(&(t[n2]), &(t[n2]), t, n2)); + } + + /* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1]) + * r[10] holds (a[0]*b[0]) + * r[32] holds (b[1]*b[1]) + * c1 holds the carry bits */ + c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2)); + if (c1) { + p = &(r[n + n2]); + lo = *p; + ln = (lo + c1) & BN_MASK2; + *p = ln; + + /* The overflow will stop before we over write + * words we should not overwrite */ + if (ln < (BN_ULONG)c1) { + do { + p++; + lo = *p; + ln = (lo + 1) & BN_MASK2; + *p = ln; + } while (ln == 0); + } + } +} + +int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx) { + int ret = 0; + int top, al, bl; + BIGNUM *rr; + int i; + BIGNUM *t = NULL; + int j = 0, k; + + al = a->top; + bl = b->top; + + if ((al == 0) || (bl == 0)) { + BN_zero(r); + return 1; + } + top = al + bl; + + BN_CTX_start(ctx); + if ((r == a) || (r == b)) { + if ((rr = BN_CTX_get(ctx)) == NULL) { + goto err; + } + } else { + rr = r; + } + rr->neg = a->neg ^ b->neg; + + i = al - bl; + if (i == 0) { + if (al == 8) { + if (bn_wexpand(rr, 16) == NULL) { + goto err; + } + rr->top = 16; + bn_mul_comba8(rr->d, a->d, b->d); + goto end; + } + } + + if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL)) { + if (i >= -1 && i <= 1) { + /* Find out the power of two lower or equal + to the longest of the two numbers */ + if (i >= 0) { + j = BN_num_bits_word((BN_ULONG)al); + } + if (i == -1) { + j = BN_num_bits_word((BN_ULONG)bl); + } + j = 1 << (j - 1); + assert(j <= al || j <= bl); + k = j + j; + t = BN_CTX_get(ctx); + if (t == NULL) { + goto err; + } + if (al > j || bl > j) { + if (bn_wexpand(t, k * 4) == NULL) { + goto err; + } + if (bn_wexpand(rr, k * 4) == NULL) { + goto err; + } + bn_mul_part_recursive(rr->d, a->d, b->d, j, al - j, bl - j, t->d); + } else { + /* al <= j || bl <= j */ + if (bn_wexpand(t, k * 2) == NULL) { + goto err; + } + if (bn_wexpand(rr, k * 2) == NULL) { + goto err; + } + bn_mul_recursive(rr->d, a->d, b->d, j, al - j, bl - j, t->d); + } + rr->top = top; + goto end; + } + } + + if (bn_wexpand(rr, top) == NULL) { + goto err; + } + rr->top = top; + bn_mul_normal(rr->d, a->d, al, b->d, bl); + +end: + bn_correct_top(rr); + if (r != rr) { + BN_copy(r, rr); + } + ret = 1; + +err: + BN_CTX_end(ctx); + return ret; +} + +/* tmp must have 2*n words */ +static void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp) { + int i, j, max; + const BN_ULONG *ap; + BN_ULONG *rp; + + max = n * 2; + ap = a; + rp = r; + rp[0] = rp[max - 1] = 0; + rp++; + j = n; + + if (--j > 0) { + ap++; + rp[j] = bn_mul_words(rp, ap, j, ap[-1]); + rp += 2; + } + + for (i = n - 2; i > 0; i--) { + j--; + ap++; + rp[j] = bn_mul_add_words(rp, ap, j, ap[-1]); + rp += 2; + } + + bn_add_words(r, r, r, max); + + /* There will not be a carry */ + + bn_sqr_words(tmp, a, n); + + bn_add_words(r, r, tmp, max); +} + +/* r is 2*n words in size, + * a and b are both n words in size. (There's not actually a 'b' here ...) + * n must be a power of 2. + * We multiply and return the result. + * t must be 2*n words in size + * We calculate + * a[0]*b[0] + * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0]) + * a[1]*b[1] + */ +static void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t) { + int n = n2 / 2; + int zero, c1; + BN_ULONG ln, lo, *p; + + if (n2 == 4) { + bn_sqr_comba4(r, a); + return; + } else if (n2 == 8) { + bn_sqr_comba8(r, a); + return; + } + if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL) { + bn_sqr_normal(r, a, n2, t); + return; + } + /* r=(a[0]-a[1])*(a[1]-a[0]) */ + c1 = bn_cmp_words(a, &(a[n]), n); + zero = 0; + if (c1 > 0) { + bn_sub_words(t, a, &(a[n]), n); + } else if (c1 < 0) { + bn_sub_words(t, &(a[n]), a, n); + } else { + zero = 1; + } + + /* The result will always be negative unless it is zero */ + p = &(t[n2 * 2]); + + if (!zero) { + bn_sqr_recursive(&(t[n2]), t, n, p); + } else { + memset(&(t[n2]), 0, n2 * sizeof(BN_ULONG)); + } + bn_sqr_recursive(r, a, n, p); + bn_sqr_recursive(&(r[n2]), &(a[n]), n, p); + + /* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero + * r[10] holds (a[0]*b[0]) + * r[32] holds (b[1]*b[1]) */ + + c1 = (int)(bn_add_words(t, r, &(r[n2]), n2)); + + /* t[32] is negative */ + c1 -= (int)(bn_sub_words(&(t[n2]), t, &(t[n2]), n2)); + + /* t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1]) + * r[10] holds (a[0]*a[0]) + * r[32] holds (a[1]*a[1]) + * c1 holds the carry bits */ + c1 += (int)(bn_add_words(&(r[n]), &(r[n]), &(t[n2]), n2)); + if (c1) { + p = &(r[n + n2]); + lo = *p; + ln = (lo + c1) & BN_MASK2; + *p = ln; + + /* The overflow will stop before we over write + * words we should not overwrite */ + if (ln < (BN_ULONG)c1) { + do { + p++; + lo = *p; + ln = (lo + 1) & BN_MASK2; + *p = ln; + } while (ln == 0); + } + } +} + +int BN_mul_word(BIGNUM *bn, BN_ULONG w) { + BN_ULONG ll; + + w &= BN_MASK2; + if (!bn->top) { + return 1; + } + + if (w == 0) { + BN_zero(bn); + return 1; + } + + ll = bn_mul_words(bn->d, bn->d, bn->top, w); + if (ll) { + if (bn_wexpand(bn, bn->top + 1) == NULL) { + return 0; + } + bn->d[bn->top++] = ll; + } + + return 1; +} + +int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx) { + int max, al; + int ret = 0; + BIGNUM *tmp, *rr; + + al = a->top; + if (al <= 0) { + r->top = 0; + r->neg = 0; + return 1; + } + + BN_CTX_start(ctx); + rr = (a != r) ? r : BN_CTX_get(ctx); + tmp = BN_CTX_get(ctx); + if (!rr || !tmp) { + goto err; + } + + max = 2 * al; /* Non-zero (from above) */ + if (bn_wexpand(rr, max) == NULL) { + goto err; + } + + if (al == 4) { + bn_sqr_comba4(rr->d, a->d); + } else if (al == 8) { + bn_sqr_comba8(rr->d, a->d); + } else { + if (al < BN_SQR_RECURSIVE_SIZE_NORMAL) { + BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL * 2]; + bn_sqr_normal(rr->d, a->d, al, t); + } else { + int j, k; + + j = BN_num_bits_word((BN_ULONG)al); + j = 1 << (j - 1); + k = j + j; + if (al == j) { + if (bn_wexpand(tmp, k * 2) == NULL) { + goto err; + } + bn_sqr_recursive(rr->d, a->d, al, tmp->d); + } else { + if (bn_wexpand(tmp, max) == NULL) { + goto err; + } + bn_sqr_normal(rr->d, a->d, al, tmp->d); + } + } + } + + rr->neg = 0; + /* If the most-significant half of the top word of 'a' is zero, then + * the square of 'a' will max-1 words. */ + if (a->d[al - 1] == (a->d[al - 1] & BN_MASK2l)) { + rr->top = max - 1; + } else { + rr->top = max; + } + + if (rr != r) { + BN_copy(r, rr); + } + ret = 1; + +err: + BN_CTX_end(ctx); + return ret; +} |