Support for "multiply high" instruction, see BN_UMULT_HIGH comment in

crypto/bn/bn_lcl.h for further details. It should be noted that for
the moment of this writing the code was tested only on Alpha. If
compiled with DEC C the C implementation exhibits 12% performance
improvement over the crypto/bn/asm/alpha.s (on EV56 box running
AlphaLinux). GNU C is (unfortunately) 8% behind the assembler
implementation. But it's OpenVMS Alpha users who *may* benefit most
as 'apps/openssl speed rsa' exhibits 6 (six) times performance
improvement over the original VMS bignum implementation. Where "*may*"
means "as soon as code is enabled though #define SIXTY_FOUR_BIT and
crypto/bn/asm/vms.mar is skipped."

1 files changed, 61 insertions, 37 deletions

diff --git a/crypto/bn/bn_asm.c b/crypto/bn/bn_asm.c
index 4d3da16a0c..a62fdcf07a 100644
--- a/crypto/bn/bn_asm.c
+++ b/crypto/bn/bn_asm.c
@@ -60,7 +60,7 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-#ifdef BN_LLONG 
+#if defined(BN_LLONG) || defined(BN_UMULT_HIGH)
 
 BN_ULONG bn_mul_add_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
 	{
@@ -69,18 +69,19 @@ BN_ULONG bn_mul_add_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
 	bn_check_num(num);
 	if (num <= 0) return(c1);
 
-	for (;;)
+	while (num&~3)
 		{
 		mul_add(rp[0],ap[0],w,c1);
-		if (--num == 0) break;
 		mul_add(rp[1],ap[1],w,c1);
-		if (--num == 0) break;
 		mul_add(rp[2],ap[2],w,c1);
-		if (--num == 0) break;
 		mul_add(rp[3],ap[3],w,c1);
-		if (--num == 0) break;
-		ap+=4;
-		rp+=4;
+		ap+=4; rp+=4; num-=4;
+		}
+	if (num)
+		{
+		mul_add(rp[0],ap[0],w,c1); if (--num==0) return c1;
+		mul_add(rp[1],ap[1],w,c1); if (--num==0) return c1;
+		mul_add(rp[2],ap[2],w,c1); return c1;
 		}
 	
 	return(c1);
@@ -93,19 +94,19 @@ BN_ULONG bn_mul_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
 	bn_check_num(num);
 	if (num <= 0) return(c1);
 
-	/* for (;;) */
-	while (1) /* circumvent egcs-1.1.2 bug */
+	while (num&~3)
 		{
 		mul(rp[0],ap[0],w,c1);
-		if (--num == 0) break;
 		mul(rp[1],ap[1],w,c1);
-		if (--num == 0) break;
 		mul(rp[2],ap[2],w,c1);
-		if (--num == 0) break;
 		mul(rp[3],ap[3],w,c1);
-		if (--num == 0) break;
-		ap+=4;
-		rp+=4;
+		ap+=4; rp+=4; num-=4;
+		}
+	if (num)
+		{
+		mul(rp[0],ap[0],w,c1); if (--num == 0) return c1;
+		mul(rp[1],ap[1],w,c1); if (--num == 0) return c1;
+		mul(rp[2],ap[2],w,c1);
 		}
 	return(c1);
 	} 
@@ -114,28 +115,19 @@ void bn_sqr_words(BN_ULONG *r, BN_ULONG *a, int n)
         {
 	bn_check_num(n);
 	if (n <= 0) return;
-	for (;;)
+	while (n&~3)
 		{
-		BN_ULLONG t;
-
-		t=(BN_ULLONG)(a[0])*(a[0]);
-		r[0]=Lw(t); r[1]=Hw(t);
-		if (--n == 0) break;
-
-		t=(BN_ULLONG)(a[1])*(a[1]);
-		r[2]=Lw(t); r[3]=Hw(t);
-		if (--n == 0) break;
-
-		t=(BN_ULLONG)(a[2])*(a[2]);
-		r[4]=Lw(t); r[5]=Hw(t);
-		if (--n == 0) break;
-
-		t=(BN_ULLONG)(a[3])*(a[3]);
-		r[6]=Lw(t); r[7]=Hw(t);
-		if (--n == 0) break;
-
-		a+=4;
-		r+=8;
+		sqr(r[0],r[1],a[0]);
+		sqr(r[2],r[3],a[1]);
+		sqr(r[4],r[5],a[2]);
+		sqr(r[6],r[7],a[3]);
+		a+=4; r+=8; n-=4;
+		}
+	if (n)
+		{
+		sqr(r[0],r[1],a[0]); if (--n == 0) return;
+		sqr(r[2],r[3],a[1]); if (--n == 0) return;
+		sqr(r[4],r[5],a[2]);
 		}
 	}
 
@@ -460,6 +452,38 @@ BN_ULONG bn_sub_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
 
 #define sqr_add_c2(a,i,j,c0,c1,c2) \
 	mul_add_c2((a)[i],(a)[j],c0,c1,c2)
+
+#elif defined(BN_UMULT_HIGH)
+
+#define mul_add_c(a,b,c0,c1,c2)	{	\
+	BN_ULONG ta=(a),tb=(b);		\
+	t1 = ta * tb;			\
+	t2 = BN_UMULT_HIGH(ta,tb);	\
+	c0 += t1; t2 += (c0<t1)?1:0;	\
+	c1 += t2; c2 += (c1<t2)?1:0;	\
+	}
+
+#define mul_add_c2(a,b,c0,c1,c2) {	\
+	BN_ULONG ta=(a),tb=(b),t0;	\
+	t1 = BN_UMULT_HIGH(ta,tb);	\
+	t0 = ta * tb;			\
+	t2 = t1+t1; c2 += (t2<t1)?1:0;	\
+	t1 = t0+t0; t2 += (t1<t0)?1:0;	\
+	c0 += t1; t2 += (c0<t1)?1:0;	\
+	c1 += t2; c2 += (c1<t2)?1:0;	\
+	}
+
+#define sqr_add_c(a,i,c0,c1,c2)	{	\
+	BN_ULONG ta=(a)[i];		\
+	t1 = ta * ta;			\
+	t2 = BN_UMULT_HIGH(ta,ta);	\
+	c0 += t1; t2 += (c0<t1)?1:0;	\
+	c1 += t2; c2 += (c1<t2)?1:0;	\
+	}
+
+#define sqr_add_c2(a,i,j,c0,c1,c2)	\
+	mul_add_c2((a)[i],(a)[j],c0,c1,c2)
+
 #else
 #define mul_add_c(a,b,c0,c1,c2) \
 	t1=LBITS(a); t2=HBITS(a); \