X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Fbn%2Fbn_mul.c;h=a0e9ec3b4694cb896a565f2953c56f53eef1da1c;hp=3c8bf23a705f89d94911e39874794b7ba77b6b92;hb=7e4cae1d2f555cbe9226b377aff4b56c9f7ddd4d;hpb=eda1f21f1af8b6f77327e7b37573af9c1ba73726

diff --git a/crypto/bn/bn_mul.c b/crypto/bn/bn_mul.c
index 3c8bf23a70..a0e9ec3b46 100644
--- a/crypto/bn/bn_mul.c
+++ b/crypto/bn/bn_mul.c
@@ -1,5 +1,5 @@
 /* crypto/bn/bn_mul.c */
-/* Copyright (C) 1995-1997 Eric Young (eay@cryptsoft.com)
+/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
  * This package is an SSL implementation written
@@ -56,44 +56,1116 @@
  * [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"
 
-/* r must be different to a and b */
-int BN_mul(r, a, b)
-BIGNUM *r;
-BIGNUM *a;
-BIGNUM *b;
+#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]
+ */
+/* dnX may not be positive, but n2/2+dnX has to be */
+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 * %d%+d\n",n2,dna,n2,dnb);
+# 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 */
+/* tnX may not be negative but less than n */
+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",
+		n, tna, n, tnb);
+# 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;
+					/* 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);
+			}
+		}
+	}
+
+/* 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;
-	int max,al,bl;
-	BN_ULONG *ap,*bp,*rp;
+#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))
 		{
-		r->top=0;
+		BN_zero(r);
 		return(1);
 		}
+	top=al+bl;
 
-	max=(al+bl);
-	if (bn_expand(r,(max)*BN_BITS2) == NULL) return(0);
-	r->top=max;
-	r->neg=a->neg^b->neg;
-	ap=a->d;
-	bp=b->d;
-	rp=r->d;
+	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;
 
-	rp[al]=bn_mul_word(rp,ap,al,*(bp++));
-	rp++;
-	for (i=1; i<bl; i++)
+#if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
+	i = al-bl;
+#endif
+#ifdef BN_MUL_COMBA
+	if (i == 0)
 		{
-		rp[al]=bn_mul_add_word(rp,ap,al,*(bp++));
-		rp++;
+# 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;
+			}
 		}
-	if (r->d[max-1] == 0) r->top--;
-	return(1);
+#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 (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 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;
+		}
+	}