sl@0: /* crypto/bn/bn_mul.c */
sl@0: /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
sl@0:  * All rights reserved.
sl@0:  *
sl@0:  * This package is an SSL implementation written
sl@0:  * by Eric Young (eay@cryptsoft.com).
sl@0:  * The implementation was written so as to conform with Netscapes SSL.
sl@0:  * 
sl@0:  * This library is free for commercial and non-commercial use as long as
sl@0:  * the following conditions are aheared to.  The following conditions
sl@0:  * apply to all code found in this distribution, be it the RC4, RSA,
sl@0:  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
sl@0:  * included with this distribution is covered by the same copyright terms
sl@0:  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
sl@0:  * 
sl@0:  * Copyright remains Eric Young's, and as such any Copyright notices in
sl@0:  * the code are not to be removed.
sl@0:  * If this package is used in a product, Eric Young should be given attribution
sl@0:  * as the author of the parts of the library used.
sl@0:  * This can be in the form of a textual message at program startup or
sl@0:  * in documentation (online or textual) provided with the package.
sl@0:  * 
sl@0:  * Redistribution and use in source and binary forms, with or without
sl@0:  * modification, are permitted provided that the following conditions
sl@0:  * are met:
sl@0:  * 1. Redistributions of source code must retain the copyright
sl@0:  *    notice, this list of conditions and the following disclaimer.
sl@0:  * 2. Redistributions in binary form must reproduce the above copyright
sl@0:  *    notice, this list of conditions and the following disclaimer in the
sl@0:  *    documentation and/or other materials provided with the distribution.
sl@0:  * 3. All advertising materials mentioning features or use of this software
sl@0:  *    must display the following acknowledgement:
sl@0:  *    "This product includes cryptographic software written by
sl@0:  *     Eric Young (eay@cryptsoft.com)"
sl@0:  *    The word 'cryptographic' can be left out if the rouines from the library
sl@0:  *    being used are not cryptographic related :-).
sl@0:  * 4. If you include any Windows specific code (or a derivative thereof) from 
sl@0:  *    the apps directory (application code) you must include an acknowledgement:
sl@0:  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
sl@0:  * 
sl@0:  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
sl@0:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
sl@0:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
sl@0:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
sl@0:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
sl@0:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
sl@0:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
sl@0:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
sl@0:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
sl@0:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
sl@0:  * SUCH DAMAGE.
sl@0:  * 
sl@0:  * The licence and distribution terms for any publically available version or
sl@0:  * derivative of this code cannot be changed.  i.e. this code cannot simply be
sl@0:  * copied and put under another distribution licence
sl@0:  * [including the GNU Public Licence.]
sl@0:  */
sl@0: 
sl@0: #ifndef BN_DEBUG
sl@0: # undef NDEBUG /* avoid conflicting definitions */
sl@0: # define NDEBUG
sl@0: #endif
sl@0: 
sl@0: #include <stdio.h>
sl@0: #include <assert.h>
sl@0: #include "cryptlib.h"
sl@0: #include "bn_lcl.h"
sl@0: 
sl@0: #if defined(OPENSSL_NO_ASM) || !defined(OPENSSL_BN_ASM_PART_WORDS)
sl@0: /* Here follows specialised variants of bn_add_words() and
sl@0:    bn_sub_words().  They have the property performing operations on
sl@0:    arrays of different sizes.  The sizes of those arrays is expressed through
sl@0:    cl, which is the common length ( basicall, min(len(a),len(b)) ), and dl,
sl@0:    which is the delta between the two lengths, calculated as len(a)-len(b).
sl@0:    All lengths are the number of BN_ULONGs...  For the operations that require
sl@0:    a result array as parameter, it must have the length cl+abs(dl).
sl@0:    These functions should probably end up in bn_asm.c as soon as there are
sl@0:    assembler counterparts for the systems that use assembler files.  */
sl@0: 
sl@0: EXPORT_C BN_ULONG bn_sub_part_words(BN_ULONG *r,
sl@0: 	const BN_ULONG *a, const BN_ULONG *b,
sl@0: 	int cl, int dl)
sl@0: 	{
sl@0: 	BN_ULONG c, t;
sl@0: 
sl@0: 	assert(cl >= 0);
sl@0: 	c = bn_sub_words(r, a, b, cl);
sl@0: 
sl@0: 	if (dl == 0)
sl@0: 		return c;
sl@0: 
sl@0: 	r += cl;
sl@0: 	a += cl;
sl@0: 	b += cl;
sl@0: 
sl@0: 	if (dl < 0)
sl@0: 		{
sl@0: #ifdef BN_COUNT
sl@0: 		fprintf(stderr, "  bn_sub_part_words %d + %d (dl < 0, c = %d)\n", cl, dl, c);
sl@0: #endif
sl@0: 		for (;;)
sl@0: 			{
sl@0: 			t = b[0];
sl@0: 			r[0] = (0-t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=1;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			t = b[1];
sl@0: 			r[1] = (0-t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=1;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			t = b[2];
sl@0: 			r[2] = (0-t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=1;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			t = b[3];
sl@0: 			r[3] = (0-t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=1;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			b += 4;
sl@0: 			r += 4;
sl@0: 			}
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		int save_dl = dl;
sl@0: #ifdef BN_COUNT
sl@0: 		fprintf(stderr, "  bn_sub_part_words %d + %d (dl > 0, c = %d)\n", cl, dl, c);
sl@0: #endif
sl@0: 		while(c)
sl@0: 			{
sl@0: 			t = a[0];
sl@0: 			r[0] = (t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=0;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			t = a[1];
sl@0: 			r[1] = (t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=0;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			t = a[2];
sl@0: 			r[2] = (t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=0;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			t = a[3];
sl@0: 			r[3] = (t-c)&BN_MASK2;
sl@0: 			if (t != 0) c=0;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			save_dl = dl;
sl@0: 			a += 4;
sl@0: 			r += 4;
sl@0: 			}
sl@0: 		if (dl > 0)
sl@0: 			{
sl@0: #ifdef BN_COUNT
sl@0: 			fprintf(stderr, "  bn_sub_part_words %d + %d (dl > 0, c == 0)\n", cl, dl);
sl@0: #endif
sl@0: 			if (save_dl > dl)
sl@0: 				{
sl@0: 				switch (save_dl - dl)
sl@0: 					{
sl@0: 				case 1:
sl@0: 					r[1] = a[1];
sl@0: 					if (--dl <= 0) break;
sl@0: 				case 2:
sl@0: 					r[2] = a[2];
sl@0: 					if (--dl <= 0) break;
sl@0: 				case 3:
sl@0: 					r[3] = a[3];
sl@0: 					if (--dl <= 0) break;
sl@0: 					}
sl@0: 				a += 4;
sl@0: 				r += 4;
sl@0: 				}
sl@0: 			}
sl@0: 		if (dl > 0)
sl@0: 			{
sl@0: #ifdef BN_COUNT
sl@0: 			fprintf(stderr, "  bn_sub_part_words %d + %d (dl > 0, copy)\n", cl, dl);
sl@0: #endif
sl@0: 			for(;;)
sl@0: 				{
sl@0: 				r[0] = a[0];
sl@0: 				if (--dl <= 0) break;
sl@0: 				r[1] = a[1];
sl@0: 				if (--dl <= 0) break;
sl@0: 				r[2] = a[2];
sl@0: 				if (--dl <= 0) break;
sl@0: 				r[3] = a[3];
sl@0: 				if (--dl <= 0) break;
sl@0: 
sl@0: 				a += 4;
sl@0: 				r += 4;
sl@0: 				}
sl@0: 			}
sl@0: 		}
sl@0: 	return c;
sl@0: 	}
sl@0: #endif
sl@0: 
sl@0: EXPORT_C BN_ULONG bn_add_part_words(BN_ULONG *r,
sl@0: 	const BN_ULONG *a, const BN_ULONG *b,
sl@0: 	int cl, int dl)
sl@0: 	{
sl@0: 	BN_ULONG c, l, t;
sl@0: 
sl@0: 	assert(cl >= 0);
sl@0: 	c = bn_add_words(r, a, b, cl);
sl@0: 
sl@0: 	if (dl == 0)
sl@0: 		return c;
sl@0: 
sl@0: 	r += cl;
sl@0: 	a += cl;
sl@0: 	b += cl;
sl@0: 
sl@0: 	if (dl < 0)
sl@0: 		{
sl@0: 		int save_dl = dl;
sl@0: #ifdef BN_COUNT
sl@0: 		fprintf(stderr, "  bn_add_part_words %d + %d (dl < 0, c = %d)\n", cl, dl, c);
sl@0: #endif
sl@0: 		while (c)
sl@0: 			{
sl@0: 			l=(c+b[0])&BN_MASK2;
sl@0: 			c=(l < c);
sl@0: 			r[0]=l;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			l=(c+b[1])&BN_MASK2;
sl@0: 			c=(l < c);
sl@0: 			r[1]=l;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			l=(c+b[2])&BN_MASK2;
sl@0: 			c=(l < c);
sl@0: 			r[2]=l;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			l=(c+b[3])&BN_MASK2;
sl@0: 			c=(l < c);
sl@0: 			r[3]=l;
sl@0: 			if (++dl >= 0) break;
sl@0: 
sl@0: 			save_dl = dl;
sl@0: 			b+=4;
sl@0: 			r+=4;
sl@0: 			}
sl@0: 		if (dl < 0)
sl@0: 			{
sl@0: #ifdef BN_COUNT
sl@0: 			fprintf(stderr, "  bn_add_part_words %d + %d (dl < 0, c == 0)\n", cl, dl);
sl@0: #endif
sl@0: 			if (save_dl < dl)
sl@0: 				{
sl@0: 				switch (dl - save_dl)
sl@0: 					{
sl@0: 				case 1:
sl@0: 					r[1] = b[1];
sl@0: 					if (++dl >= 0) break;
sl@0: 				case 2:
sl@0: 					r[2] = b[2];
sl@0: 					if (++dl >= 0) break;
sl@0: 				case 3:
sl@0: 					r[3] = b[3];
sl@0: 					if (++dl >= 0) break;
sl@0: 					}
sl@0: 				b += 4;
sl@0: 				r += 4;
sl@0: 				}
sl@0: 			}
sl@0: 		if (dl < 0)
sl@0: 			{
sl@0: #ifdef BN_COUNT
sl@0: 			fprintf(stderr, "  bn_add_part_words %d + %d (dl < 0, copy)\n", cl, dl);
sl@0: #endif
sl@0: 			for(;;)
sl@0: 				{
sl@0: 				r[0] = b[0];
sl@0: 				if (++dl >= 0) break;
sl@0: 				r[1] = b[1];
sl@0: 				if (++dl >= 0) break;
sl@0: 				r[2] = b[2];
sl@0: 				if (++dl >= 0) break;
sl@0: 				r[3] = b[3];
sl@0: 				if (++dl >= 0) break;
sl@0: 
sl@0: 				b += 4;
sl@0: 				r += 4;
sl@0: 				}
sl@0: 			}
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		int save_dl = dl;
sl@0: #ifdef BN_COUNT
sl@0: 		fprintf(stderr, "  bn_add_part_words %d + %d (dl > 0)\n", cl, dl);
sl@0: #endif
sl@0: 		while (c)
sl@0: 			{
sl@0: 			t=(a[0]+c)&BN_MASK2;
sl@0: 			c=(t < c);
sl@0: 			r[0]=t;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			t=(a[1]+c)&BN_MASK2;
sl@0: 			c=(t < c);
sl@0: 			r[1]=t;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			t=(a[2]+c)&BN_MASK2;
sl@0: 			c=(t < c);
sl@0: 			r[2]=t;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			t=(a[3]+c)&BN_MASK2;
sl@0: 			c=(t < c);
sl@0: 			r[3]=t;
sl@0: 			if (--dl <= 0) break;
sl@0: 
sl@0: 			save_dl = dl;
sl@0: 			a+=4;
sl@0: 			r+=4;
sl@0: 			}
sl@0: #ifdef BN_COUNT
sl@0: 		fprintf(stderr, "  bn_add_part_words %d + %d (dl > 0, c == 0)\n", cl, dl);
sl@0: #endif
sl@0: 		if (dl > 0)
sl@0: 			{
sl@0: 			if (save_dl > dl)
sl@0: 				{
sl@0: 				switch (save_dl - dl)
sl@0: 					{
sl@0: 				case 1:
sl@0: 					r[1] = a[1];
sl@0: 					if (--dl <= 0) break;
sl@0: 				case 2:
sl@0: 					r[2] = a[2];
sl@0: 					if (--dl <= 0) break;
sl@0: 				case 3:
sl@0: 					r[3] = a[3];
sl@0: 					if (--dl <= 0) break;
sl@0: 					}
sl@0: 				a += 4;
sl@0: 				r += 4;
sl@0: 				}
sl@0: 			}
sl@0: 		if (dl > 0)
sl@0: 			{
sl@0: #ifdef BN_COUNT
sl@0: 			fprintf(stderr, "  bn_add_part_words %d + %d (dl > 0, copy)\n", cl, dl);
sl@0: #endif
sl@0: 			for(;;)
sl@0: 				{
sl@0: 				r[0] = a[0];
sl@0: 				if (--dl <= 0) break;
sl@0: 				r[1] = a[1];
sl@0: 				if (--dl <= 0) break;
sl@0: 				r[2] = a[2];
sl@0: 				if (--dl <= 0) break;
sl@0: 				r[3] = a[3];
sl@0: 				if (--dl <= 0) break;
sl@0: 
sl@0: 				a += 4;
sl@0: 				r += 4;
sl@0: 				}
sl@0: 			}
sl@0: 		}
sl@0: 	return c;
sl@0: 	}
sl@0: 
sl@0: #ifdef BN_RECURSION
sl@0: /* Karatsuba recursive multiplication algorithm
sl@0:  * (cf. Knuth, The Art of Computer Programming, Vol. 2) */
sl@0: 
sl@0: /* r is 2*n2 words in size,
sl@0:  * a and b are both n2 words in size.
sl@0:  * n2 must be a power of 2.
sl@0:  * We multiply and return the result.
sl@0:  * t must be 2*n2 words in size
sl@0:  * We calculate
sl@0:  * a[0]*b[0]
sl@0:  * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
sl@0:  * a[1]*b[1]
sl@0:  */
sl@0: EXPORT_C void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
sl@0: 	int dna, int dnb, BN_ULONG *t)
sl@0: 	{
sl@0: 	int n=n2/2,c1,c2;
sl@0: 	int tna=n+dna, tnb=n+dnb;
sl@0: 	unsigned int neg,zero;
sl@0: 	BN_ULONG ln,lo,*p;
sl@0: 
sl@0: # ifdef BN_COUNT
sl@0: 	fprintf(stderr," bn_mul_recursive %d * %d\n",n2,n2);
sl@0: # endif
sl@0: # ifdef BN_MUL_COMBA
sl@0: #  if 0
sl@0: 	if (n2 == 4)
sl@0: 		{
sl@0: 		bn_mul_comba4(r,a,b);
sl@0: 		return;
sl@0: 		}
sl@0: #  endif
sl@0: 	/* Only call bn_mul_comba 8 if n2 == 8 and the
sl@0: 	 * two arrays are complete [steve]
sl@0: 	 */
sl@0: 	if (n2 == 8 && dna == 0 && dnb == 0)
sl@0: 		{
sl@0: 		bn_mul_comba8(r,a,b);
sl@0: 		return; 
sl@0: 		}
sl@0: # endif /* BN_MUL_COMBA */
sl@0: 	/* Else do normal multiply */
sl@0: 	if (n2 < BN_MUL_RECURSIVE_SIZE_NORMAL)
sl@0: 		{
sl@0: 		bn_mul_normal(r,a,n2+dna,b,n2+dnb);
sl@0: 		if ((dna + dnb) < 0)
sl@0: 			memset(&r[2*n2 + dna + dnb], 0,
sl@0: 				sizeof(BN_ULONG) * -(dna + dnb));
sl@0: 		return;
sl@0: 		}
sl@0: 	/* r=(a[0]-a[1])*(b[1]-b[0]) */
sl@0: 	c1=bn_cmp_part_words(a,&(a[n]),tna,n-tna);
sl@0: 	c2=bn_cmp_part_words(&(b[n]),b,tnb,tnb-n);
sl@0: 	zero=neg=0;
sl@0: 	switch (c1*3+c2)
sl@0: 		{
sl@0: 	case -4:
sl@0: 		bn_sub_part_words(t,      &(a[n]),a,      tna,tna-n); /* - */
sl@0: 		bn_sub_part_words(&(t[n]),b,      &(b[n]),tnb,n-tnb); /* - */
sl@0: 		break;
sl@0: 	case -3:
sl@0: 		zero=1;
sl@0: 		break;
sl@0: 	case -2:
sl@0: 		bn_sub_part_words(t,      &(a[n]),a,      tna,tna-n); /* - */
sl@0: 		bn_sub_part_words(&(t[n]),&(b[n]),b,      tnb,tnb-n); /* + */
sl@0: 		neg=1;
sl@0: 		break;
sl@0: 	case -1:
sl@0: 	case 0:
sl@0: 	case 1:
sl@0: 		zero=1;
sl@0: 		break;
sl@0: 	case 2:
sl@0: 		bn_sub_part_words(t,      a,      &(a[n]),tna,n-tna); /* + */
sl@0: 		bn_sub_part_words(&(t[n]),b,      &(b[n]),tnb,n-tnb); /* - */
sl@0: 		neg=1;
sl@0: 		break;
sl@0: 	case 3:
sl@0: 		zero=1;
sl@0: 		break;
sl@0: 	case 4:
sl@0: 		bn_sub_part_words(t,      a,      &(a[n]),tna,n-tna);
sl@0: 		bn_sub_part_words(&(t[n]),&(b[n]),b,      tnb,tnb-n);
sl@0: 		break;
sl@0: 		}
sl@0: 
sl@0: # ifdef BN_MUL_COMBA
sl@0: 	if (n == 4 && dna == 0 && dnb == 0) /* XXX: bn_mul_comba4 could take
sl@0: 					       extra args to do this well */
sl@0: 		{
sl@0: 		if (!zero)
sl@0: 			bn_mul_comba4(&(t[n2]),t,&(t[n]));
sl@0: 		else
sl@0: 			memset(&(t[n2]),0,8*sizeof(BN_ULONG));
sl@0: 		
sl@0: 		bn_mul_comba4(r,a,b);
sl@0: 		bn_mul_comba4(&(r[n2]),&(a[n]),&(b[n]));
sl@0: 		}
sl@0: 	else if (n == 8 && dna == 0 && dnb == 0) /* XXX: bn_mul_comba8 could
sl@0: 						    take extra args to do this
sl@0: 						    well */
sl@0: 		{
sl@0: 		if (!zero)
sl@0: 			bn_mul_comba8(&(t[n2]),t,&(t[n]));
sl@0: 		else
sl@0: 			memset(&(t[n2]),0,16*sizeof(BN_ULONG));
sl@0: 		
sl@0: 		bn_mul_comba8(r,a,b);
sl@0: 		bn_mul_comba8(&(r[n2]),&(a[n]),&(b[n]));
sl@0: 		}
sl@0: 	else
sl@0: # endif /* BN_MUL_COMBA */
sl@0: 		{
sl@0: 		p= &(t[n2*2]);
sl@0: 		if (!zero)
sl@0: 			bn_mul_recursive(&(t[n2]),t,&(t[n]),n,0,0,p);
sl@0: 		else
sl@0: 			memset(&(t[n2]),0,n2*sizeof(BN_ULONG));
sl@0: 		bn_mul_recursive(r,a,b,n,0,0,p);
sl@0: 		bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),n,dna,dnb,p);
sl@0: 		}
sl@0: 
sl@0: 	/* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
sl@0: 	 * r[10] holds (a[0]*b[0])
sl@0: 	 * r[32] holds (b[1]*b[1])
sl@0: 	 */
sl@0: 
sl@0: 	c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
sl@0: 
sl@0: 	if (neg) /* if t[32] is negative */
sl@0: 		{
sl@0: 		c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		/* Might have a carry */
sl@0: 		c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2));
sl@0: 		}
sl@0: 
sl@0: 	/* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
sl@0: 	 * r[10] holds (a[0]*b[0])
sl@0: 	 * r[32] holds (b[1]*b[1])
sl@0: 	 * c1 holds the carry bits
sl@0: 	 */
sl@0: 	c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
sl@0: 	if (c1)
sl@0: 		{
sl@0: 		p= &(r[n+n2]);
sl@0: 		lo= *p;
sl@0: 		ln=(lo+c1)&BN_MASK2;
sl@0: 		*p=ln;
sl@0: 
sl@0: 		/* The overflow will stop before we over write
sl@0: 		 * words we should not overwrite */
sl@0: 		if (ln < (BN_ULONG)c1)
sl@0: 			{
sl@0: 			do	{
sl@0: 				p++;
sl@0: 				lo= *p;
sl@0: 				ln=(lo+1)&BN_MASK2;
sl@0: 				*p=ln;
sl@0: 				} while (ln == 0);
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: /* n+tn is the word length
sl@0:  * t needs to be n*4 is size, as does r */
sl@0: EXPORT_C void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
sl@0: 	     int tna, int tnb, BN_ULONG *t)
sl@0: 	{
sl@0: 	int i,j,n2=n*2;
sl@0: 	int c1,c2,neg,zero;
sl@0: 	BN_ULONG ln,lo,*p;
sl@0: 
sl@0: # ifdef BN_COUNT
sl@0: 	fprintf(stderr," bn_mul_part_recursive (%d+%d) * (%d+%d)\n",
sl@0: 		tna, n, tnb, n);
sl@0: # endif
sl@0: 	if (n < 8)
sl@0: 		{
sl@0: 		bn_mul_normal(r,a,n+tna,b,n+tnb);
sl@0: 		return;
sl@0: 		}
sl@0: 
sl@0: 	/* r=(a[0]-a[1])*(b[1]-b[0]) */
sl@0: 	c1=bn_cmp_part_words(a,&(a[n]),tna,n-tna);
sl@0: 	c2=bn_cmp_part_words(&(b[n]),b,tnb,tnb-n);
sl@0: 	zero=neg=0;
sl@0: 	switch (c1*3+c2)
sl@0: 		{
sl@0: 	case -4:
sl@0: 		bn_sub_part_words(t,      &(a[n]),a,      tna,tna-n); /* - */
sl@0: 		bn_sub_part_words(&(t[n]),b,      &(b[n]),tnb,n-tnb); /* - */
sl@0: 		break;
sl@0: 	case -3:
sl@0: 		zero=1;
sl@0: 		/* break; */
sl@0: 	case -2:
sl@0: 		bn_sub_part_words(t,      &(a[n]),a,      tna,tna-n); /* - */
sl@0: 		bn_sub_part_words(&(t[n]),&(b[n]),b,      tnb,tnb-n); /* + */
sl@0: 		neg=1;
sl@0: 		break;
sl@0: 	case -1:
sl@0: 	case 0:
sl@0: 	case 1:
sl@0: 		zero=1;
sl@0: 		/* break; */
sl@0: 	case 2:
sl@0: 		bn_sub_part_words(t,      a,      &(a[n]),tna,n-tna); /* + */
sl@0: 		bn_sub_part_words(&(t[n]),b,      &(b[n]),tnb,n-tnb); /* - */
sl@0: 		neg=1;
sl@0: 		break;
sl@0: 	case 3:
sl@0: 		zero=1;
sl@0: 		/* break; */
sl@0: 	case 4:
sl@0: 		bn_sub_part_words(t,      a,      &(a[n]),tna,n-tna);
sl@0: 		bn_sub_part_words(&(t[n]),&(b[n]),b,      tnb,tnb-n);
sl@0: 		break;
sl@0: 		}
sl@0: 		/* The zero case isn't yet implemented here. The speedup
sl@0: 		   would probably be negligible. */
sl@0: # if 0
sl@0: 	if (n == 4)
sl@0: 		{
sl@0: 		bn_mul_comba4(&(t[n2]),t,&(t[n]));
sl@0: 		bn_mul_comba4(r,a,b);
sl@0: 		bn_mul_normal(&(r[n2]),&(a[n]),tn,&(b[n]),tn);
sl@0: 		memset(&(r[n2+tn*2]),0,sizeof(BN_ULONG)*(n2-tn*2));
sl@0: 		}
sl@0: 	else
sl@0: # endif
sl@0: 	if (n == 8)
sl@0: 		{
sl@0: 		bn_mul_comba8(&(t[n2]),t,&(t[n]));
sl@0: 		bn_mul_comba8(r,a,b);
sl@0: 		bn_mul_normal(&(r[n2]),&(a[n]),tna,&(b[n]),tnb);
sl@0: 		memset(&(r[n2+tna+tnb]),0,sizeof(BN_ULONG)*(n2-tna-tnb));
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		p= &(t[n2*2]);
sl@0: 		bn_mul_recursive(&(t[n2]),t,&(t[n]),n,0,0,p);
sl@0: 		bn_mul_recursive(r,a,b,n,0,0,p);
sl@0: 		i=n/2;
sl@0: 		/* If there is only a bottom half to the number,
sl@0: 		 * just do it */
sl@0: 		if (tna > tnb)
sl@0: 			j = tna - i;
sl@0: 		else
sl@0: 			j = tnb - i;
sl@0: 		if (j == 0)
sl@0: 			{
sl@0: 			bn_mul_recursive(&(r[n2]),&(a[n]),&(b[n]),
sl@0: 				i,tna-i,tnb-i,p);
sl@0: 			memset(&(r[n2+i*2]),0,sizeof(BN_ULONG)*(n2-i*2));
sl@0: 			}
sl@0: 		else if (j > 0) /* eg, n == 16, i == 8 and tn == 11 */
sl@0: 				{
sl@0: 				bn_mul_part_recursive(&(r[n2]),&(a[n]),&(b[n]),
sl@0: 					i,tna-i,tnb-i,p);
sl@0: 				memset(&(r[n2+tna+tnb]),0,
sl@0: 					sizeof(BN_ULONG)*(n2-tna-tnb));
sl@0: 				}
sl@0: 		else /* (j < 0) eg, n == 16, i == 8 and tn == 5 */
sl@0: 			{
sl@0: 			memset(&(r[n2]),0,sizeof(BN_ULONG)*n2);
sl@0: 			if (tna < BN_MUL_RECURSIVE_SIZE_NORMAL
sl@0: 				&& tnb < BN_MUL_RECURSIVE_SIZE_NORMAL)
sl@0: 				{
sl@0: 				bn_mul_normal(&(r[n2]),&(a[n]),tna,&(b[n]),tnb);
sl@0: 				}
sl@0: 			else
sl@0: 				{
sl@0: 				for (;;)
sl@0: 					{
sl@0: 					i/=2;
sl@0: 					if (i <= tna && tna == tnb)
sl@0: 						{
sl@0: 						bn_mul_recursive(&(r[n2]),
sl@0: 							&(a[n]),&(b[n]),
sl@0: 							i,tna-i,tnb-i,p);
sl@0: 						break;
sl@0: 						}
sl@0: 					else if (i < tna || i < tnb)
sl@0: 						{
sl@0: 						bn_mul_part_recursive(&(r[n2]),
sl@0: 							&(a[n]),&(b[n]),
sl@0: 							i,tna-i,tnb-i,p);
sl@0: 						break;
sl@0: 						}
sl@0: 					}
sl@0: 				}
sl@0: 			}
sl@0: 		}
sl@0: 
sl@0: 	/* t[32] holds (a[0]-a[1])*(b[1]-b[0]), c1 is the sign
sl@0: 	 * r[10] holds (a[0]*b[0])
sl@0: 	 * r[32] holds (b[1]*b[1])
sl@0: 	 */
sl@0: 
sl@0: 	c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
sl@0: 
sl@0: 	if (neg) /* if t[32] is negative */
sl@0: 		{
sl@0: 		c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		/* Might have a carry */
sl@0: 		c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),t,n2));
sl@0: 		}
sl@0: 
sl@0: 	/* t[32] holds (a[0]-a[1])*(b[1]-b[0])+(a[0]*b[0])+(a[1]*b[1])
sl@0: 	 * r[10] holds (a[0]*b[0])
sl@0: 	 * r[32] holds (b[1]*b[1])
sl@0: 	 * c1 holds the carry bits
sl@0: 	 */
sl@0: 	c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
sl@0: 	if (c1)
sl@0: 		{
sl@0: 		p= &(r[n+n2]);
sl@0: 		lo= *p;
sl@0: 		ln=(lo+c1)&BN_MASK2;
sl@0: 		*p=ln;
sl@0: 
sl@0: 		/* The overflow will stop before we over write
sl@0: 		 * words we should not overwrite */
sl@0: 		if (ln < (BN_ULONG)c1)
sl@0: 			{
sl@0: 			do	{
sl@0: 				p++;
sl@0: 				lo= *p;
sl@0: 				ln=(lo+1)&BN_MASK2;
sl@0: 				*p=ln;
sl@0: 				} while (ln == 0);
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: /* a and b must be the same size, which is n2.
sl@0:  * r needs to be n2 words and t needs to be n2*2
sl@0:  */
sl@0: EXPORT_C void bn_mul_low_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
sl@0: 	     BN_ULONG *t)
sl@0: 	{
sl@0: 	int n=n2/2;
sl@0: 
sl@0: # ifdef BN_COUNT
sl@0: 	fprintf(stderr," bn_mul_low_recursive %d * %d\n",n2,n2);
sl@0: # endif
sl@0: 
sl@0: 	bn_mul_recursive(r,a,b,n,0,0,&(t[0]));
sl@0: 	if (n >= BN_MUL_LOW_RECURSIVE_SIZE_NORMAL)
sl@0: 		{
sl@0: 		bn_mul_low_recursive(&(t[0]),&(a[0]),&(b[n]),n,&(t[n2]));
sl@0: 		bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
sl@0: 		bn_mul_low_recursive(&(t[0]),&(a[n]),&(b[0]),n,&(t[n2]));
sl@0: 		bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		bn_mul_low_normal(&(t[0]),&(a[0]),&(b[n]),n);
sl@0: 		bn_mul_low_normal(&(t[n]),&(a[n]),&(b[0]),n);
sl@0: 		bn_add_words(&(r[n]),&(r[n]),&(t[0]),n);
sl@0: 		bn_add_words(&(r[n]),&(r[n]),&(t[n]),n);
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: /* a and b must be the same size, which is n2.
sl@0:  * r needs to be n2 words and t needs to be n2*2
sl@0:  * l is the low words of the output.
sl@0:  * t needs to be n2*3
sl@0:  */
sl@0: EXPORT_C void bn_mul_high(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, BN_ULONG *l, int n2,
sl@0: 	     BN_ULONG *t)
sl@0: 	{
sl@0: 	int i,n;
sl@0: 	int c1,c2;
sl@0: 	int neg,oneg,zero;
sl@0: 	BN_ULONG ll,lc,*lp,*mp;
sl@0: 
sl@0: # ifdef BN_COUNT
sl@0: 	fprintf(stderr," bn_mul_high %d * %d\n",n2,n2);
sl@0: # endif
sl@0: 	n=n2/2;
sl@0: 
sl@0: 	/* Calculate (al-ah)*(bh-bl) */
sl@0: 	neg=zero=0;
sl@0: 	c1=bn_cmp_words(&(a[0]),&(a[n]),n);
sl@0: 	c2=bn_cmp_words(&(b[n]),&(b[0]),n);
sl@0: 	switch (c1*3+c2)
sl@0: 		{
sl@0: 	case -4:
sl@0: 		bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
sl@0: 		bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
sl@0: 		break;
sl@0: 	case -3:
sl@0: 		zero=1;
sl@0: 		break;
sl@0: 	case -2:
sl@0: 		bn_sub_words(&(r[0]),&(a[n]),&(a[0]),n);
sl@0: 		bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
sl@0: 		neg=1;
sl@0: 		break;
sl@0: 	case -1:
sl@0: 	case 0:
sl@0: 	case 1:
sl@0: 		zero=1;
sl@0: 		break;
sl@0: 	case 2:
sl@0: 		bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
sl@0: 		bn_sub_words(&(r[n]),&(b[0]),&(b[n]),n);
sl@0: 		neg=1;
sl@0: 		break;
sl@0: 	case 3:
sl@0: 		zero=1;
sl@0: 		break;
sl@0: 	case 4:
sl@0: 		bn_sub_words(&(r[0]),&(a[0]),&(a[n]),n);
sl@0: 		bn_sub_words(&(r[n]),&(b[n]),&(b[0]),n);
sl@0: 		break;
sl@0: 		}
sl@0: 		
sl@0: 	oneg=neg;
sl@0: 	/* t[10] = (a[0]-a[1])*(b[1]-b[0]) */
sl@0: 	/* r[10] = (a[1]*b[1]) */
sl@0: # ifdef BN_MUL_COMBA
sl@0: 	if (n == 8)
sl@0: 		{
sl@0: 		bn_mul_comba8(&(t[0]),&(r[0]),&(r[n]));
sl@0: 		bn_mul_comba8(r,&(a[n]),&(b[n]));
sl@0: 		}
sl@0: 	else
sl@0: # endif
sl@0: 		{
sl@0: 		bn_mul_recursive(&(t[0]),&(r[0]),&(r[n]),n,0,0,&(t[n2]));
sl@0: 		bn_mul_recursive(r,&(a[n]),&(b[n]),n,0,0,&(t[n2]));
sl@0: 		}
sl@0: 
sl@0: 	/* s0 == low(al*bl)
sl@0: 	 * s1 == low(ah*bh)+low((al-ah)*(bh-bl))+low(al*bl)+high(al*bl)
sl@0: 	 * We know s0 and s1 so the only unknown is high(al*bl)
sl@0: 	 * high(al*bl) == s1 - low(ah*bh+s0+(al-ah)*(bh-bl))
sl@0: 	 * high(al*bl) == s1 - (r[0]+l[0]+t[0])
sl@0: 	 */
sl@0: 	if (l != NULL)
sl@0: 		{
sl@0: 		lp= &(t[n2+n]);
sl@0: 		c1=(int)(bn_add_words(lp,&(r[0]),&(l[0]),n));
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		c1=0;
sl@0: 		lp= &(r[0]);
sl@0: 		}
sl@0: 
sl@0: 	if (neg)
sl@0: 		neg=(int)(bn_sub_words(&(t[n2]),lp,&(t[0]),n));
sl@0: 	else
sl@0: 		{
sl@0: 		bn_add_words(&(t[n2]),lp,&(t[0]),n);
sl@0: 		neg=0;
sl@0: 		}
sl@0: 
sl@0: 	if (l != NULL)
sl@0: 		{
sl@0: 		bn_sub_words(&(t[n2+n]),&(l[n]),&(t[n2]),n);
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		lp= &(t[n2+n]);
sl@0: 		mp= &(t[n2]);
sl@0: 		for (i=0; i<n; i++)
sl@0: 			lp[i]=((~mp[i])+1)&BN_MASK2;
sl@0: 		}
sl@0: 
sl@0: 	/* s[0] = low(al*bl)
sl@0: 	 * t[3] = high(al*bl)
sl@0: 	 * t[10] = (a[0]-a[1])*(b[1]-b[0]) neg is the sign
sl@0: 	 * r[10] = (a[1]*b[1])
sl@0: 	 */
sl@0: 	/* R[10] = al*bl
sl@0: 	 * R[21] = al*bl + ah*bh + (a[0]-a[1])*(b[1]-b[0])
sl@0: 	 * R[32] = ah*bh
sl@0: 	 */
sl@0: 	/* R[1]=t[3]+l[0]+r[0](+-)t[0] (have carry/borrow)
sl@0: 	 * R[2]=r[0]+t[3]+r[1](+-)t[1] (have carry/borrow)
sl@0: 	 * R[3]=r[1]+(carry/borrow)
sl@0: 	 */
sl@0: 	if (l != NULL)
sl@0: 		{
sl@0: 		lp= &(t[n2]);
sl@0: 		c1= (int)(bn_add_words(lp,&(t[n2+n]),&(l[0]),n));
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		lp= &(t[n2+n]);
sl@0: 		c1=0;
sl@0: 		}
sl@0: 	c1+=(int)(bn_add_words(&(t[n2]),lp,  &(r[0]),n));
sl@0: 	if (oneg)
sl@0: 		c1-=(int)(bn_sub_words(&(t[n2]),&(t[n2]),&(t[0]),n));
sl@0: 	else
sl@0: 		c1+=(int)(bn_add_words(&(t[n2]),&(t[n2]),&(t[0]),n));
sl@0: 
sl@0: 	c2 =(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n2+n]),n));
sl@0: 	c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(r[n]),n));
sl@0: 	if (oneg)
sl@0: 		c2-=(int)(bn_sub_words(&(r[0]),&(r[0]),&(t[n]),n));
sl@0: 	else
sl@0: 		c2+=(int)(bn_add_words(&(r[0]),&(r[0]),&(t[n]),n));
sl@0: 	
sl@0: 	if (c1 != 0) /* Add starting at r[0], could be +ve or -ve */
sl@0: 		{
sl@0: 		i=0;
sl@0: 		if (c1 > 0)
sl@0: 			{
sl@0: 			lc=c1;
sl@0: 			do	{
sl@0: 				ll=(r[i]+lc)&BN_MASK2;
sl@0: 				r[i++]=ll;
sl@0: 				lc=(lc > ll);
sl@0: 				} while (lc);
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			lc= -c1;
sl@0: 			do	{
sl@0: 				ll=r[i];
sl@0: 				r[i++]=(ll-lc)&BN_MASK2;
sl@0: 				lc=(lc > ll);
sl@0: 				} while (lc);
sl@0: 			}
sl@0: 		}
sl@0: 	if (c2 != 0) /* Add starting at r[1] */
sl@0: 		{
sl@0: 		i=n;
sl@0: 		if (c2 > 0)
sl@0: 			{
sl@0: 			lc=c2;
sl@0: 			do	{
sl@0: 				ll=(r[i]+lc)&BN_MASK2;
sl@0: 				r[i++]=ll;
sl@0: 				lc=(lc > ll);
sl@0: 				} while (lc);
sl@0: 			}
sl@0: 		else
sl@0: 			{
sl@0: 			lc= -c2;
sl@0: 			do	{
sl@0: 				ll=r[i];
sl@0: 				r[i++]=(ll-lc)&BN_MASK2;
sl@0: 				lc=(lc > ll);
sl@0: 				} while (lc);
sl@0: 			}
sl@0: 		}
sl@0: 	}
sl@0: #endif /* BN_RECURSION */
sl@0: 
sl@0: EXPORT_C int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
sl@0: 	{
sl@0: 	int ret=0;
sl@0: 	int top,al,bl;
sl@0: 	BIGNUM *rr;
sl@0: #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
sl@0: 	int i;
sl@0: #endif
sl@0: #ifdef BN_RECURSION
sl@0: 	BIGNUM *t=NULL;
sl@0: 	int j=0,k;
sl@0: #endif
sl@0: 
sl@0: #ifdef BN_COUNT
sl@0: 	fprintf(stderr,"BN_mul %d * %d\n",a->top,b->top);
sl@0: #endif
sl@0: 
sl@0: 	bn_check_top(a);
sl@0: 	bn_check_top(b);
sl@0: 	bn_check_top(r);
sl@0: 
sl@0: 	al=a->top;
sl@0: 	bl=b->top;
sl@0: 
sl@0: 	if ((al == 0) || (bl == 0))
sl@0: 		{
sl@0: 		BN_zero(r);
sl@0: 		return(1);
sl@0: 		}
sl@0: 	top=al+bl;
sl@0: 
sl@0: 	BN_CTX_start(ctx);
sl@0: 	if ((r == a) || (r == b))
sl@0: 		{
sl@0: 		if ((rr = BN_CTX_get(ctx)) == NULL) goto err;
sl@0: 		}
sl@0: 	else
sl@0: 		rr = r;
sl@0: 	rr->neg=a->neg^b->neg;
sl@0: 
sl@0: #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
sl@0: 	i = al-bl;
sl@0: #endif
sl@0: #ifdef BN_MUL_COMBA
sl@0: 	if (i == 0)
sl@0: 		{
sl@0: # if 0
sl@0: 		if (al == 4)
sl@0: 			{
sl@0: 			if (bn_wexpand(rr,8) == NULL) goto err;
sl@0: 			rr->top=8;
sl@0: 			bn_mul_comba4(rr->d,a->d,b->d);
sl@0: 			goto end;
sl@0: 			}
sl@0: # endif
sl@0: 		if (al == 8)
sl@0: 			{
sl@0: 			if (bn_wexpand(rr,16) == NULL) goto err;
sl@0: 			rr->top=16;
sl@0: 			bn_mul_comba8(rr->d,a->d,b->d);
sl@0: 			goto end;
sl@0: 			}
sl@0: 		}
sl@0: #endif /* BN_MUL_COMBA */
sl@0: #ifdef BN_RECURSION
sl@0: 	if ((al >= BN_MULL_SIZE_NORMAL) && (bl >= BN_MULL_SIZE_NORMAL))
sl@0: 		{
sl@0: 		if (i >= -1 && i <= 1)
sl@0: 			{
sl@0: 			int sav_j =0;
sl@0: 			/* Find out the power of two lower or equal
sl@0: 			   to the longest of the two numbers */
sl@0: 			if (i >= 0)
sl@0: 				{
sl@0: 				j = BN_num_bits_word((BN_ULONG)al);
sl@0: 				}
sl@0: 			if (i == -1)
sl@0: 				{
sl@0: 				j = BN_num_bits_word((BN_ULONG)bl);
sl@0: 				}
sl@0: 			sav_j = j;
sl@0: 			j = 1<<(j-1);
sl@0: 			assert(j <= al || j <= bl);
sl@0: 			k = j+j;
sl@0: 			t = BN_CTX_get(ctx);
sl@0: 			if (al > j || bl > j)
sl@0: 				{
sl@0: 				bn_wexpand(t,k*4);
sl@0: 				bn_wexpand(rr,k*4);
sl@0: 				bn_mul_part_recursive(rr->d,a->d,b->d,
sl@0: 					j,al-j,bl-j,t->d);
sl@0: 				}
sl@0: 			else	/* al <= j || bl <= j */
sl@0: 				{
sl@0: 				bn_wexpand(t,k*2);
sl@0: 				bn_wexpand(rr,k*2);
sl@0: 				bn_mul_recursive(rr->d,a->d,b->d,
sl@0: 					j,al-j,bl-j,t->d);
sl@0: 				}
sl@0: 			rr->top=top;
sl@0: 			goto end;
sl@0: 			}
sl@0: #if 0
sl@0: 		if (i == 1 && !BN_get_flags(b,BN_FLG_STATIC_DATA))
sl@0: 			{
sl@0: 			BIGNUM *tmp_bn = (BIGNUM *)b;
sl@0: 			if (bn_wexpand(tmp_bn,al) == NULL) goto err;
sl@0: 			tmp_bn->d[bl]=0;
sl@0: 			bl++;
sl@0: 			i--;
sl@0: 			}
sl@0: 		else if (i == -1 && !BN_get_flags(a,BN_FLG_STATIC_DATA))
sl@0: 			{
sl@0: 			BIGNUM *tmp_bn = (BIGNUM *)a;
sl@0: 			if (bn_wexpand(tmp_bn,bl) == NULL) goto err;
sl@0: 			tmp_bn->d[al]=0;
sl@0: 			al++;
sl@0: 			i++;
sl@0: 			}
sl@0: 		if (i == 0)
sl@0: 			{
sl@0: 			/* symmetric and > 4 */
sl@0: 			/* 16 or larger */
sl@0: 			j=BN_num_bits_word((BN_ULONG)al);
sl@0: 			j=1<<(j-1);
sl@0: 			k=j+j;
sl@0: 			t = BN_CTX_get(ctx);
sl@0: 			if (al == j) /* exact multiple */
sl@0: 				{
sl@0: 				if (bn_wexpand(t,k*2) == NULL) goto err;
sl@0: 				if (bn_wexpand(rr,k*2) == NULL) goto err;
sl@0: 				bn_mul_recursive(rr->d,a->d,b->d,al,t->d);
sl@0: 				}
sl@0: 			else
sl@0: 				{
sl@0: 				if (bn_wexpand(t,k*4) == NULL) goto err;
sl@0: 				if (bn_wexpand(rr,k*4) == NULL) goto err;
sl@0: 				bn_mul_part_recursive(rr->d,a->d,b->d,al-j,j,t->d);
sl@0: 				}
sl@0: 			rr->top=top;
sl@0: 			goto end;
sl@0: 			}
sl@0: #endif
sl@0: 		}
sl@0: #endif /* BN_RECURSION */
sl@0: 	if (bn_wexpand(rr,top) == NULL) goto err;
sl@0: 	rr->top=top;
sl@0: 	bn_mul_normal(rr->d,a->d,al,b->d,bl);
sl@0: 
sl@0: #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
sl@0: end:
sl@0: #endif
sl@0: 	bn_correct_top(rr);
sl@0: 	if (r != rr) BN_copy(r,rr);
sl@0: 	ret=1;
sl@0: err:
sl@0: 	bn_check_top(r);
sl@0: 	BN_CTX_end(ctx);
sl@0: 	return(ret);
sl@0: 	}
sl@0: 
sl@0: EXPORT_C void bn_mul_normal(BN_ULONG *r, BN_ULONG *a, int na, BN_ULONG *b, int nb)
sl@0: 	{
sl@0: 	BN_ULONG *rr;
sl@0: 
sl@0: #ifdef BN_COUNT
sl@0: 	fprintf(stderr," bn_mul_normal %d * %d\n",na,nb);
sl@0: #endif
sl@0: 
sl@0: 	if (na < nb)
sl@0: 		{
sl@0: 		int itmp;
sl@0: 		BN_ULONG *ltmp;
sl@0: 
sl@0: 		itmp=na; na=nb; nb=itmp;
sl@0: 		ltmp=a;   a=b;   b=ltmp;
sl@0: 
sl@0: 		}
sl@0: 	rr= &(r[na]);
sl@0: 	if (nb <= 0)
sl@0: 		{
sl@0: 		(void)bn_mul_words(r,a,na,0);
sl@0: 		return;
sl@0: 		}
sl@0: 	else
sl@0: 		rr[0]=bn_mul_words(r,a,na,b[0]);
sl@0: 
sl@0: 	for (;;)
sl@0: 		{
sl@0: 		if (--nb <= 0) return;
sl@0: 		rr[1]=bn_mul_add_words(&(r[1]),a,na,b[1]);
sl@0: 		if (--nb <= 0) return;
sl@0: 		rr[2]=bn_mul_add_words(&(r[2]),a,na,b[2]);
sl@0: 		if (--nb <= 0) return;
sl@0: 		rr[3]=bn_mul_add_words(&(r[3]),a,na,b[3]);
sl@0: 		if (--nb <= 0) return;
sl@0: 		rr[4]=bn_mul_add_words(&(r[4]),a,na,b[4]);
sl@0: 		rr+=4;
sl@0: 		r+=4;
sl@0: 		b+=4;
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: EXPORT_C void bn_mul_low_normal(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
sl@0: 	{
sl@0: #ifdef BN_COUNT
sl@0: 	fprintf(stderr," bn_mul_low_normal %d * %d\n",n,n);
sl@0: #endif
sl@0: 	bn_mul_words(r,a,n,b[0]);
sl@0: 
sl@0: 	for (;;)
sl@0: 		{
sl@0: 		if (--n <= 0) return;
sl@0: 		bn_mul_add_words(&(r[1]),a,n,b[1]);
sl@0: 		if (--n <= 0) return;
sl@0: 		bn_mul_add_words(&(r[2]),a,n,b[2]);
sl@0: 		if (--n <= 0) return;
sl@0: 		bn_mul_add_words(&(r[3]),a,n,b[3]);
sl@0: 		if (--n <= 0) return;
sl@0: 		bn_mul_add_words(&(r[4]),a,n,b[4]);
sl@0: 		r+=4;
sl@0: 		b+=4;
sl@0: 		}
sl@0: 	}