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- /* crypto/bn/bn_mul.c */
- /* 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.]
- */
- #ifndef BN_DEBUG
- # undef NDEBUG /* avoid conflicting definitions */
- # define NDEBUG
- #endif
- #include <stdio.h>
- #include <assert.h>
- #include "cryptlib.h"
- #include "bn_lcl.h"
- #if defined(OPENSSL_NO_ASM) || !defined(OPENSSL_BN_ASM_PART_WORDS)
- /* 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. */
- 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)
- {
- #ifdef BN_COUNT
- fprintf(stderr, " bn_sub_part_words %d + %d (dl < 0, c = %d)\n", cl, dl, c);
- #endif
- 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;
- #ifdef BN_COUNT
- fprintf(stderr, " bn_sub_part_words %d + %d (dl > 0, c = %d)\n", cl, dl, c);
- #endif
- 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)
- {
- #ifdef BN_COUNT
- fprintf(stderr, " bn_sub_part_words %d + %d (dl > 0, c == 0)\n", cl, dl);
- #endif
- 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)
- {
- #ifdef BN_COUNT
- fprintf(stderr, " bn_sub_part_words %d + %d (dl > 0, copy)\n", cl, dl);
- #endif
- 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;
- }
- #endif
- BN_ULONG bn_add_part_words(BN_ULONG *r,
- const BN_ULONG *a, const BN_ULONG *b,
- int cl, int dl)
- {
- BN_ULONG c, l, t;
- assert(cl >= 0);
- c = bn_add_words(r, a, b, cl);
- if (dl == 0)
- return c;
- r += cl;
- a += cl;
- b += cl;
- if (dl < 0)
- {
- int save_dl = dl;
- #ifdef BN_COUNT
- fprintf(stderr, " bn_add_part_words %d + %d (dl < 0, c = %d)\n", cl, dl, c);
- #endif
- while (c)
- {
- l=(c+b[0])&BN_MASK2;
- c=(l < c);
- r[0]=l;
- if (++dl >= 0) break;
- l=(c+b[1])&BN_MASK2;
- c=(l < c);
- r[1]=l;
- if (++dl >= 0) break;
- l=(c+b[2])&BN_MASK2;
- c=(l < c);
- r[2]=l;
- if (++dl >= 0) break;
- l=(c+b[3])&BN_MASK2;
- c=(l < c);
- r[3]=l;
- if (++dl >= 0) break;
- save_dl = dl;
- b+=4;
- r+=4;
- }
- if (dl < 0)
- {
- #ifdef BN_COUNT
- fprintf(stderr, " bn_add_part_words %d + %d (dl < 0, c == 0)\n", cl, dl);
- #endif
- if (save_dl < dl)
- {
- switch (dl - save_dl)
- {
- case 1:
- r[1] = b[1];
- if (++dl >= 0) break;
- case 2:
- r[2] = b[2];
- if (++dl >= 0) break;
- case 3:
- r[3] = b[3];
- if (++dl >= 0) break;
- }
- b += 4;
- r += 4;
- }
- }
- if (dl < 0)
- {
- #ifdef BN_COUNT
- fprintf(stderr, " bn_add_part_words %d + %d (dl < 0, copy)\n", cl, dl);
- #endif
- for(;;)
- {
- r[0] = b[0];
- if (++dl >= 0) break;
- r[1] = b[1];
- if (++dl >= 0) break;
- r[2] = b[2];
- if (++dl >= 0) break;
- r[3] = b[3];
- if (++dl >= 0) break;
- b += 4;
- r += 4;
- }
- }
- }
- else
- {
- int save_dl = dl;
- #ifdef BN_COUNT
- fprintf(stderr, " bn_add_part_words %d + %d (dl > 0)\n", cl, dl);
- #endif
- while (c)
- {
- t=(a[0]+c)&BN_MASK2;
- c=(t < c);
- r[0]=t;
- if (--dl <= 0) break;
- t=(a[1]+c)&BN_MASK2;
- c=(t < c);
- r[1]=t;
- if (--dl <= 0) break;
- t=(a[2]+c)&BN_MASK2;
- c=(t < c);
- r[2]=t;
- if (--dl <= 0) break;
- t=(a[3]+c)&BN_MASK2;
- c=(t < c);
- r[3]=t;
- if (--dl <= 0) break;
- save_dl = dl;
- a+=4;
- r+=4;
- }
- #ifdef BN_COUNT
- fprintf(stderr, " bn_add_part_words %d + %d (dl > 0, c == 0)\n", cl, dl);
- #endif
- 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)
- {
- #ifdef BN_COUNT
- fprintf(stderr, " bn_add_part_words %d + %d (dl > 0, copy)\n", cl, dl);
- #endif
- 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;
- }
- #ifdef BN_RECURSION
- /* 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]
- */
- 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;
- # ifdef BN_COUNT
- fprintf(stderr," bn_mul_recursive %d * %d\n",n2,n2);
- # endif
- # ifdef BN_MUL_COMBA
- # if 0
- if (n2 == 4)
- {
- bn_mul_comba4(r,a,b);
- return;
- }
- # endif
- /* 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;
- }
- # endif /* BN_MUL_COMBA */
- /* 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;
- }
- # ifdef BN_MUL_COMBA
- 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
- # endif /* BN_MUL_COMBA */
- {
- 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 */
- 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,zero;
- BN_ULONG ln,lo,*p;
- # ifdef BN_COUNT
- fprintf(stderr," bn_mul_part_recursive (%d+%d) * (%d+%d)\n",
- tna, n, tnb, n);
- # endif
- 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);
- 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;
- }
- /* The zero case isn't yet implemented here. The speedup
- would probably be negligible. */
- # if 0
- if (n == 4)
- {
- bn_mul_comba4(&(t[n2]),t,&(t[n]));
- bn_mul_comba4(r,a,b);
- bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
- memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
- }
- else
- # endif
- 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;
- 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);
- }
- }
- }
- /* a and b must be the same size, which is n2.
- * r needs to be n2 words and t needs to be n2*2
- */
- void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
- BN_ULONG *t)
- {
- int n=n2/2;
- # ifdef BN_COUNT
- fprintf(stderr," bn_mul_low_recursive %d * %d\n",n2,n2);
- # endif
- bn_mul_recursive(r,a,b,n,0,0,&(t[0]));
- if (n >= BN_MUL_LOW_RECURSIVE_SIZE_NORMAL)
- {
- bn_mul_low_recursive(&(t[0]),&(a[0]),&(b[n]),n,&(t[n2]));
- bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
- bn_mul_low_recursive(&(t[0]),&(a[n]),&(b[0]),n,&(t[n2]));
- bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
- }
- else
- {
- bn_mul_low_normal(&(t[0]),&(a[0]),&(b[n]),n);
- bn_mul_low_normal(&(t[n]),&(a[n]),&(b[0]),n);
- bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
- bn_add_words(&(r[n]),&(r[n]),&(t[n]),n);
- }
- }
- /* a and b must be the same size, which is n2.
- * r needs to be n2 words and t needs to be n2*2
- * l is the low words of the output.
- * t needs to be n2*3
- */
- void bn_mul_high(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, BN_ULONG *l, int n2,
- BN_ULONG *t)
- {
- int i,n;
- int c1,c2;
- int neg,oneg,zero;
- BN_ULONG ll,lc,*lp,*mp;
- # ifdef BN_COUNT
- fprintf(stderr," bn_mul_high %d * %d\n",n2,n2);
- # endif
- n=n2/2;
- /* Calculate (al-ah)*(bh-bl) */
- neg=zero=0;
- c1=bn_cmp_words(&(a[0]),&(a[n]),n);
- c2=bn_cmp_words(&(b[n]),&(b[0]),n);
- switch (c1*3+c2)
- {
- case -4:
- bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
- bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
- break;
- case -3:
- zero=1;
- break;
- case -2:
- bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
- bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
- neg=1;
- break;
- case -1:
- case 0:
- case 1:
- zero=1;
- break;
- case 2:
- bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
- bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
- neg=1;
- break;
- case 3:
- zero=1;
- break;
- case 4:
- bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
- bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
- break;
- }
-
- oneg=neg;
- /* t[10] = (a[0]-a[1])*(b[1]-b[0]) */
- /* r[10] = (a[1]*b[1]) */
- # ifdef BN_MUL_COMBA
- if (n == 8)
- {
- bn_mul_comba8(&(t[0]),&(r[0]),&(r[n]));
- bn_mul_comba8(r,&(a[n]),&(b[n]));
- }
- else
- # endif
- {
- bn_mul_recursive(&(t[0]),&(r[0]),&(r[n]),n,0,0,&(t[n2]));
- bn_mul_recursive(r,&(a[n]),&(b[n]),n,0,0,&(t[n2]));
- }
- /* s0 == low(al*bl)
- * s1 == low(ah*bh)+low((al-ah)*(bh-bl))+low(al*bl)+high(al*bl)
- * We know s0 and s1 so the only unknown is high(al*bl)
- * high(al*bl) == s1 - low(ah*bh+s0+(al-ah)*(bh-bl))
- * high(al*bl) == s1 - (r[0]+l[0]+t[0])
- */
- if (l != NULL)
- {
- lp= &(t[n2+n]);
- c1=(int)(bn_add_words(lp,&(r[0]),&(l[0]),n));
- }
- else
- {
- c1=0;
- lp= &(r[0]);
- }
- if (neg)
- neg=(int)(bn_sub_words(&(t[n2]),lp,&(t[0]),n));
- else
- {
- bn_add_words(&(t[n2]),lp,&(t[0]),n);
- neg=0;
- }
- if (l != NULL)
- {
- bn_sub_words(&(t[n2+n]),&(l[n]),&(t[n2]),n);
- }
- else
- {
- lp= &(t[n2+n]);
- mp= &(t[n2]);
- for (i=0; i<n; i++)
- lp[i]=((~mp[i])+1)&BN_MASK2;
- }
- /* s[0] = low(al*bl)
- * t[3] = high(al*bl)
- * t[10] = (a[0]-a[1])*(b[1]-b[0]) neg is the sign
- * r[10] = (a[1]*b[1])
- */
- /* R[10] = al*bl
- * R[21] = al*bl + ah*bh + (a[0]-a[1])*(b[1]-b[0])
- * R[32] = ah*bh
- */
- /* R[1]=t[3]+l[0]+r[0](+-)t[0] (have carry/borrow)
- * R[2]=r[0]+t[3]+r[1](+-)t[1] (have carry/borrow)
- * R[3]=r[1]+(carry/borrow)
- */
- if (l != NULL)
- {
- lp= &(t[n2]);
- c1= (int)(bn_add_words(lp,&(t[n2+n]),&(l[0]),n));
- }
- else
- {
- lp= &(t[n2+n]);
- c1=0;
- }
- c1+=(int)(bn_add_words(&(t[n2]),lp, &(r[0]),n));
- if (oneg)
- c1-=(int)(bn_sub_words(&(t[n2]),&(t[n2]),&(t[0]),n));
- else
- c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),&(t[0]),n));
- c2 =(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n2+n]),n));
- c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(r[n]),n));
- if (oneg)
- c2-=(int)(bn_sub_words(&(r[0]),&(r[0]),&(t[n]),n));
- else
- c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n]),n));
-
- if (c1 != 0) /* Add starting at r[0], could be +ve or -ve */
- {
- i=0;
- if (c1 > 0)
- {
- lc=c1;
- do {
- ll=(r[i]+lc)&BN_MASK2;
- r[i++]=ll;
- lc=(lc > ll);
- } while (lc);
- }
- else
- {
- lc= -c1;
- do {
- ll=r[i];
- r[i++]=(ll-lc)&BN_MASK2;
- lc=(lc > ll);
- } while (lc);
- }
- }
- if (c2 != 0) /* Add starting at r[1] */
- {
- i=n;
- if (c2 > 0)
- {
- lc=c2;
- do {
- ll=(r[i]+lc)&BN_MASK2;
- r[i++]=ll;
- lc=(lc > ll);
- } while (lc);
- }
- else
- {
- lc= -c2;
- do {
- ll=r[i];
- r[i++]=(ll-lc)&BN_MASK2;
- lc=(lc > ll);
- } while (lc);
- }
- }
- }
- #endif /* BN_RECURSION */
- int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
- {
- int ret=0;
- int top,al,bl;
- BIGNUM *rr;
- #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
- int i;
- #endif
- #ifdef BN_RECURSION
- BIGNUM *t=NULL;
- int j=0,k;
- #endif
- #ifdef BN_COUNT
- fprintf(stderr,"BN_mul %d * %d\n",a->top,b->top);
- #endif
- bn_check_top(a);
- bn_check_top(b);
- bn_check_top(r);
- 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;
- #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
- i = al-bl;
- #endif
- #ifdef BN_MUL_COMBA
- if (i == 0)
- {
- # if 0
- if (al == 4)
- {
- if (bn_wexpand(rr,8) == NULL) goto err;
- rr->top=8;
- bn_mul_comba4(rr->d,a->d,b->d);
- goto end;
- }
- # endif
- 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;
- }
- }
- #endif /* BN_MUL_COMBA */
- #ifdef BN_RECURSION
- if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL))
- {
- if (i >= -1 && i <= 1)
- {
- int sav_j =0;
- /* 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);
- }
- sav_j = j;
- j = 1<<(j-1);
- assert(j <= al || j <= bl);
- k = j+j;
- t = BN_CTX_get(ctx);
- if (al > j || bl > j)
- {
- bn_wexpand(t,k*4);
- bn_wexpand(rr,k*4);
- bn_mul_part_recursive(rr->d,a->d,b->d,
- j,al-j,bl-j,t->d);
- }
- else /* al <= j || bl <= j */
- {
- bn_wexpand(t,k*2);
- bn_wexpand(rr,k*2);
- bn_mul_recursive(rr->d,a->d,b->d,
- j,al-j,bl-j,t->d);
- }
- rr->top=top;
- goto end;
- }
- #if 0
- if (i == 1 && !BN_get_flags(b,BN_FLG_STATIC_DATA))
- {
- BIGNUM *tmp_bn = (BIGNUM *)b;
- if (bn_wexpand(tmp_bn,al) == NULL) goto err;
- tmp_bn->d[bl]=0;
- bl++;
- i--;
- }
- else if (i == -1 && !BN_get_flags(a,BN_FLG_STATIC_DATA))
- {
- BIGNUM *tmp_bn = (BIGNUM *)a;
- if (bn_wexpand(tmp_bn,bl) == NULL) goto err;
- tmp_bn->d[al]=0;
- al++;
- i++;
- }
- if (i == 0)
- {
- /* symmetric and > 4 */
- /* 16 or larger */
- j=BN_num_bits_word((BN_ULONG)al);
- j=1<<(j-1);
- k=j+j;
- t = BN_CTX_get(ctx);
- if (al == j) /* exact multiple */
- {
- 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,al,t->d);
- }
- else
- {
- 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,al-j,j,t->d);
- }
- rr->top=top;
- goto end;
- }
- #endif
- }
- #endif /* BN_RECURSION */
- if (bn_wexpand(rr,top) == NULL) goto err;
- rr->top=top;
- bn_mul_normal(rr->d,a->d,al,b->d,bl);
- #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
- end:
- #endif
- bn_correct_top(rr);
- if (r != rr) BN_copy(r,rr);
- ret=1;
- err:
- bn_check_top(r);
- BN_CTX_end(ctx);
- return(ret);
- }
- void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
- {
- BN_ULONG *rr;
- #ifdef BN_COUNT
- fprintf(stderr," bn_mul_normal %d * %d\n",na,nb);
- #endif
- 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)
- {
- #ifdef BN_COUNT
- fprintf(stderr," bn_mul_low_normal %d * %d\n",n,n);
- #endif
- 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;
- }
- }
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