Reserve for SMALL_FOOTPRINT bn_asm.c. Currently OPENSSL_SMALL_FOOTPRINT
[openssl.git] / crypto / bn / bn_asm.c
index 286a0f1..741cf81 100644 (file)
  * [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"
 
-#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)
+BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w)
        {
        BN_ULONG c1=0;
 
-       bn_check_num(num);
+       assert(num >= 0);
        if (num <= 0) return(c1);
 
-       for (;;)
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       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;
+               }
+#endif
+       while (num)
+               {
+               mul_add(rp[0],ap[0],w,c1);
+               ap++; rp++; num--;
                }
        
        return(c1);
        } 
 
-BN_ULONG bn_mul_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
+BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w)
        {
        BN_ULONG c1=0;
 
-       bn_check_num(num);
+       assert(num >= 0);
        if (num <= 0) return(c1);
 
-       /* for (;;) */
-       while (1) /* circumvent egcs-1.1.2 bug */
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       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;
+               }
+#endif
+       while (num)
+               {
+               mul(rp[0],ap[0],w,c1);
+               ap++; rp++; num--;
                }
        return(c1);
        } 
 
-void bn_sqr_words(BN_ULONG *r, BN_ULONG *a, int n)
+void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n)
         {
-       bn_check_num(n);
+       assert(n >= 0);
        if (n <= 0) return;
-       for (;;)
-               {
-               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;
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (n&~3)
+               {
+               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;
+               }
+#endif
+       while (n)
+               {
+               sqr(r[0],r[1],a[0]);
+               a++; r+=2; n--;
                }
        }
 
-#else
+#else /* !(defined(BN_LLONG) || defined(BN_UMULT_HIGH)) */
 
-BN_ULONG bn_mul_add_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
+BN_ULONG bn_mul_add_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w)
        {
        BN_ULONG c=0;
        BN_ULONG bl,bh;
 
-       bn_check_num(num);
+       assert(num >= 0);
        if (num <= 0) return((BN_ULONG)0);
 
        bl=LBITS(w);
        bh=HBITS(w);
 
-       for (;;)
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (num&~3)
                {
                mul_add(rp[0],ap[0],bl,bh,c);
-               if (--num == 0) break;
                mul_add(rp[1],ap[1],bl,bh,c);
-               if (--num == 0) break;
                mul_add(rp[2],ap[2],bl,bh,c);
-               if (--num == 0) break;
                mul_add(rp[3],ap[3],bl,bh,c);
-               if (--num == 0) break;
-               ap+=4;
-               rp+=4;
+               ap+=4; rp+=4; num-=4;
+               }
+#endif
+       while (num)
+               {
+               mul_add(rp[0],ap[0],bl,bh,c);
+               ap++; rp++; num--;
                }
        return(c);
        } 
 
-BN_ULONG bn_mul_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
+BN_ULONG bn_mul_words(BN_ULONG *rp, const BN_ULONG *ap, int num, BN_ULONG w)
        {
        BN_ULONG carry=0;
        BN_ULONG bl,bh;
 
-       bn_check_num(num);
+       assert(num >= 0);
        if (num <= 0) return((BN_ULONG)0);
 
        bl=LBITS(w);
        bh=HBITS(w);
 
-       for (;;)
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (num&~3)
                {
                mul(rp[0],ap[0],bl,bh,carry);
-               if (--num == 0) break;
                mul(rp[1],ap[1],bl,bh,carry);
-               if (--num == 0) break;
                mul(rp[2],ap[2],bl,bh,carry);
-               if (--num == 0) break;
                mul(rp[3],ap[3],bl,bh,carry);
-               if (--num == 0) break;
-               ap+=4;
-               rp+=4;
+               ap+=4; rp+=4; num-=4;
+               }
+#endif
+       while (num)
+               {
+               mul(rp[0],ap[0],bl,bh,carry);
+               ap++; rp++; num--;
                }
        return(carry);
        } 
 
-void bn_sqr_words(BN_ULONG *r, BN_ULONG *a, int n)
+void bn_sqr_words(BN_ULONG *r, const BN_ULONG *a, int n)
         {
-       bn_check_num(n);
+       assert(n >= 0);
        if (n <= 0) return;
-       for (;;)
+
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (n&~3)
                {
                sqr64(r[0],r[1],a[0]);
-               if (--n == 0) break;
-
                sqr64(r[2],r[3],a[1]);
-               if (--n == 0) break;
-
                sqr64(r[4],r[5],a[2]);
-               if (--n == 0) break;
-
                sqr64(r[6],r[7],a[3]);
-               if (--n == 0) break;
-
-               a+=4;
-               r+=8;
+               a+=4; r+=8; n-=4;
+               }
+#endif
+       while (n)
+               {
+               sqr64(r[0],r[1],a[0]);
+               a++; r+=2; n--;
                }
        }
 
-#endif
+#endif /* !(defined(BN_LLONG) || defined(BN_UMULT_HIGH)) */
 
 #if defined(BN_LLONG) && defined(BN_DIV2W)
 
@@ -229,7 +234,7 @@ BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
 
 #else
 
-/* Divide h-l by d and return the result. */
+/* Divide h,l by d and return the result. */
 /* I need to test this some more :-( */
 BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
        {
@@ -239,13 +244,8 @@ BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
        if (d == 0) return(BN_MASK2);
 
        i=BN_num_bits_word(d);
-       if ((i != BN_BITS2) && (h > (BN_ULONG)1<<i))
-               {
-#if !defined(NO_STDIO) && !defined(WIN16)
-               fprintf(stderr,"Division would overflow (%d)\n",i);
-#endif
-               abort();
-               }
+       assert((i == BN_BITS2) || (h <= (BN_ULONG)1<<i));
+
        i=BN_BITS2-i;
        if (h >= d) h-=d;
 
@@ -264,18 +264,20 @@ BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
                else
                        q=h/dh;
 
+               th=q*dh;
+               tl=dl*q;
                for (;;)
                        {
-                       t=(h-(th=q*dh));
-                       tl=BN_MASK2;
+                       t=h-th;
                        if ((t&BN_MASK2h) ||
-                               ((tl=dl*q) <= (
+                               ((tl) <= (
                                        (t<<BN_BITS4)|
                                        ((l&BN_MASK2h)>>BN_BITS4))))
                                break;
                        q--;
+                       th-=dh;
+                       tl-=dl;
                        }
-               if (tl==BN_MASK2) tl=q*dl;
                t=(tl>>BN_BITS4);
                tl=(tl<<BN_BITS4)&BN_MASK2h;
                th+=t;
@@ -298,54 +300,54 @@ BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
        ret|=q;
        return(ret);
        }
-#endif
+#endif /* !defined(BN_LLONG) && defined(BN_DIV2W) */
 
 #ifdef BN_LLONG
-BN_ULONG bn_add_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
+BN_ULONG bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b, int n)
         {
        BN_ULLONG ll=0;
 
-       bn_check_num(n);
+       assert(n >= 0);
        if (n <= 0) return((BN_ULONG)0);
 
-       for (;;)
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (n&~3)
                {
                ll+=(BN_ULLONG)a[0]+b[0];
                r[0]=(BN_ULONG)ll&BN_MASK2;
                ll>>=BN_BITS2;
-               if (--n <= 0) break;
-
                ll+=(BN_ULLONG)a[1]+b[1];
                r[1]=(BN_ULONG)ll&BN_MASK2;
                ll>>=BN_BITS2;
-               if (--n <= 0) break;
-
                ll+=(BN_ULLONG)a[2]+b[2];
                r[2]=(BN_ULONG)ll&BN_MASK2;
                ll>>=BN_BITS2;
-               if (--n <= 0) break;
-
                ll+=(BN_ULLONG)a[3]+b[3];
                r[3]=(BN_ULONG)ll&BN_MASK2;
                ll>>=BN_BITS2;
-               if (--n <= 0) break;
-
-               a+=4;
-               b+=4;
-               r+=4;
+               a+=4; b+=4; r+=4; n-=4;
+               }
+#endif
+       while (n)
+               {
+               ll+=(BN_ULLONG)a[0]+b[0];
+               r[0]=(BN_ULONG)ll&BN_MASK2;
+               ll>>=BN_BITS2;
+               a++; b++; r++; n--;
                }
        return((BN_ULONG)ll);
        }
-#else
-BN_ULONG bn_add_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
+#else /* !BN_LLONG */
+BN_ULONG bn_add_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b, int n)
         {
        BN_ULONG c,l,t;
 
-       bn_check_num(n);
+       assert(n >= 0);
        if (n <= 0) return((BN_ULONG)0);
 
        c=0;
-       for (;;)
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (n&~3)
                {
                t=a[0];
                t=(t+c)&BN_MASK2;
@@ -353,84 +355,89 @@ BN_ULONG bn_add_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
                l=(t+b[0])&BN_MASK2;
                c+=(l < t);
                r[0]=l;
-               if (--n <= 0) break;
-
                t=a[1];
                t=(t+c)&BN_MASK2;
                c=(t < c);
                l=(t+b[1])&BN_MASK2;
                c+=(l < t);
                r[1]=l;
-               if (--n <= 0) break;
-
                t=a[2];
                t=(t+c)&BN_MASK2;
                c=(t < c);
                l=(t+b[2])&BN_MASK2;
                c+=(l < t);
                r[2]=l;
-               if (--n <= 0) break;
-
                t=a[3];
                t=(t+c)&BN_MASK2;
                c=(t < c);
                l=(t+b[3])&BN_MASK2;
                c+=(l < t);
                r[3]=l;
-               if (--n <= 0) break;
-
-               a+=4;
-               b+=4;
-               r+=4;
+               a+=4; b+=4; r+=4; n-=4;
+               }
+#endif
+       while(n)
+               {
+               t=a[0];
+               t=(t+c)&BN_MASK2;
+               c=(t < c);
+               l=(t+b[0])&BN_MASK2;
+               c+=(l < t);
+               r[0]=l;
+               a++; b++; r++; n--;
                }
        return((BN_ULONG)c);
        }
-#endif
+#endif /* !BN_LLONG */
 
-BN_ULONG bn_sub_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
+BN_ULONG bn_sub_words(BN_ULONG *r, const BN_ULONG *a, const BN_ULONG *b, int n)
         {
        BN_ULONG t1,t2;
        int c=0;
 
-       bn_check_num(n);
+       assert(n >= 0);
        if (n <= 0) return((BN_ULONG)0);
 
-       for (;;)
+#ifndef OPENSSL_SMALL_FOOTPRINT
+       while (n&~3)
                {
                t1=a[0]; t2=b[0];
                r[0]=(t1-t2-c)&BN_MASK2;
                if (t1 != t2) c=(t1 < t2);
-               if (--n <= 0) break;
-
                t1=a[1]; t2=b[1];
                r[1]=(t1-t2-c)&BN_MASK2;
                if (t1 != t2) c=(t1 < t2);
-               if (--n <= 0) break;
-
                t1=a[2]; t2=b[2];
                r[2]=(t1-t2-c)&BN_MASK2;
                if (t1 != t2) c=(t1 < t2);
-               if (--n <= 0) break;
-
                t1=a[3]; t2=b[3];
                r[3]=(t1-t2-c)&BN_MASK2;
                if (t1 != t2) c=(t1 < t2);
-               if (--n <= 0) break;
-
-               a+=4;
-               b+=4;
-               r+=4;
+               a+=4; b+=4; r+=4; n-=4;
+               }
+#endif
+       while (n)
+               {
+               t1=a[0]; t2=b[0];
+               r[0]=(t1-t2-c)&BN_MASK2;
+               if (t1 != t2) c=(t1 < t2);
+               a++; b++; r++; n--;
                }
        return(c);
        }
 
-#ifdef BN_MUL_COMBA
+#if defined(BN_MUL_COMBA) && !defined(OPENSSL_SMALL_FOOTPRINT)
 
 #undef bn_mul_comba8
 #undef bn_mul_comba4
 #undef bn_sqr_comba8
 #undef bn_sqr_comba4
 
+/* mul_add_c(a,b,c0,c1,c2)  -- c+=a*b for three word number c=(c2,c1,c0) */
+/* mul_add_c2(a,b,c0,c1,c2) -- c+=2*a*b for three word number c=(c2,c1,c0) */
+/* sqr_add_c(a,i,c0,c1,c2)  -- c+=a[i]^2 for three word number c=(c2,c1,c0) */
+/* sqr_add_c2(a,i,c0,c1,c2) -- c+=2*a[i]*a[j] for three word number c=(c2,c1,c0) */
+
 #ifdef BN_LLONG
 #define mul_add_c(a,b,c0,c1,c2) \
        t=(BN_ULLONG)a*b; \
@@ -458,7 +465,67 @@ 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)
-#else
+
+#elif defined(BN_UMULT_LOHI)
+
+#define mul_add_c(a,b,c0,c1,c2)        {       \
+       BN_ULONG ta=(a),tb=(b);         \
+       BN_UMULT_LOHI(t1,t2,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;      \
+       BN_UMULT_LOHI(t0,t1,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];             \
+       BN_UMULT_LOHI(t1,t2,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)
+
+#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 /* !BN_LLONG */
 #define mul_add_c(a,b,c0,c1,c2) \
        t1=LBITS(a); t2=HBITS(a); \
        bl=LBITS(b); bh=HBITS(b); \
@@ -485,7 +552,7 @@ 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)
-#endif
+#endif /* !BN_LLONG */
 
 void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
        {
@@ -641,7 +708,7 @@ void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
        r[7]=c2;
        }
 
-void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a)
+void bn_sqr_comba8(BN_ULONG *r, const BN_ULONG *a)
        {
 #ifdef BN_LLONG
        BN_ULLONG t,tt;
@@ -722,7 +789,7 @@ void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a)
        r[15]=c1;
        }
 
-void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a)
+void bn_sqr_comba4(BN_ULONG *r, const BN_ULONG *a)
        {
 #ifdef BN_LLONG
        BN_ULLONG t,tt;
@@ -760,18 +827,95 @@ void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a)
        r[6]=c1;
        r[7]=c2;
        }
+
+#ifdef OPENSSL_BN_ASM_MONT
+/*
+ * This is essentially reference implementation, which may or may not
+ * result in performance improvement. E.g. on IA-32 this does give 40%
+ * faster rsa1024 private key operations and 10% faster rsa4096 ones,
+ * while on AMD64 it improves rsa1024 sign only by 10% and *worsens*
+ * rsa4096 sign by 15%. Once again, it's a reference implementation,
+ * one to be used as start-point for platform-specific assembler.
+ */
+void bn_mul_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp, const BN_ULONG *np,BN_ULONG n0, int num)
+       {
+       BN_ULONG c0,c1,ml,*tp;
+#ifdef mul64
+       BN_ULONG mh;
+#endif
+       volatile BN_ULONG *vp;
+       int i=0,j;
+
+       vp = tp = alloca((num+2)*sizeof(BN_ULONG));
+
+       tp[num]   = bn_mul_words(tp,ap,num,bp[0]);
+       tp[num+1] = 0;
+       goto enter;
+
+       for(i=0;i<num;i++)
+               {
+               c0 = bn_mul_add_words(tp,ap,num,bp[i]);
+               c1 = (tp[num] + c0)&BN_MASK2;
+               tp[num]   = c1;
+               tp[num+1] = (c1<c0?1:0);
+       enter:
+               c1  = tp[0];
+               ml = (c1*n0)&BN_MASK2;
+               c0 = 0;
+#ifdef mul64
+               mh = HBITS(ml);
+               ml = LBITS(ml);
+               mul_add(c1,np[0],ml,mh,c0);
 #else
+               mul_add(c1,ml,np[0],c0);
+#endif
+               for(j=1;j<num;j++)
+                       {
+                       c1 = tp[j];
+#ifdef mul64
+                       mul_add(c1,np[j],ml,mh,c0);
+#else
+                       mul_add(c1,ml,np[j],c0);
+#endif
+                       tp[j-1] = c1&BN_MASK2;
+                       }
+               c1        = (tp[num] + c0)&BN_MASK2;
+               tp[num-1] = c1;
+               tp[num]   = tp[num+1] + (c1<c0?1:0);
+               }
+
+       if (tp[num]!=0 || tp[num-1]>=np[num-1])
+               {
+               c0 = bn_sub_words(rp,tp,np,num);
+               if (tp[num]!=0 || c0==0)
+                       {
+                       for(i=0;i<num+2;i++)    vp[i] = 0;
+                       return;
+                       }
+               }
+       for(i=0;i<num;i++)      rp[i] = tp[i],  vp[i] = 0;
+       vp[num]   = 0;
+       vp[num+1] = 0;
+       }
+
+void bn_sqr_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *np,BN_ULONG n0, int num)
+       {
+       bn_mul_mont(rp,ap,ap,np,n0,num);
+       }
+#endif /* OPENSSL_BN_ASM_MONT */
+
+#else /* !BN_MUL_COMBA */
 
 /* hmm... is it faster just to do a multiply? */
 #undef bn_sqr_comba4
-void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a)
+void bn_sqr_comba4(BN_ULONG *r, const BN_ULONG *a)
        {
        BN_ULONG t[8];
        bn_sqr_normal(r,a,4,t);
        }
 
 #undef bn_sqr_comba8
-void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a)
+void bn_sqr_comba8(BN_ULONG *r, const BN_ULONG *a)
        {
        BN_ULONG t[16];
        bn_sqr_normal(r,a,8,t);
@@ -797,4 +941,49 @@ void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
        r[15]=bn_mul_add_words(&(r[7]),a,8,b[7]);
        }
 
-#endif /* BN_COMBA */
+#ifdef OPENSSL_BN_ASM_MONT
+void bn_mul_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *bp, const BN_ULONG *np,BN_ULONG n0, int num)
+       {
+       BN_ULONG c0,c1,*tp;
+       volatile BN_ULONG *vp;
+       int i=0,j;
+
+       vp = tp = alloca((num+2)*sizeof(BN_ULONG));
+
+       for(i=0;i<=num;i++)     tp[i]=0;
+
+       for(i=0;i<num;i++)
+               {
+               c0         = bn_mul_add_words(tp,ap,num,bp[i]);
+               c1         = tp[num] + c0;
+               tp[num]    = c1;
+               tp[num+1]  = (c1<c0?1:0);
+
+               c0         = bn_mul_add_words(tp,np,num,tp[0]*n0);
+               c1         = tp[num] + c0;
+               tp[num]    = c1;
+               tp[num+1] += (c1<c0?1:0);
+               for(j=0;j<=num;j++)     tp[j]=tp[j+1];
+               }
+
+       if (tp[num]!=0 || tp[num-1]>=np[num-1])
+               {
+               c0 = bn_sub_words(rp,tp,np,num);
+               if (tp[num]!=0 || c0==0)
+                       {
+                       for(i=0;i<num+2;i++)    vp[i] = 0;
+                       return;
+                       }
+               }
+       for(i=0;i<num;i++)      rp[i] = tp[i],  vp[i] = 0;
+       vp[num]   = 0;
+       vp[num+1] = 0;
+       }
+
+void bn_sqr_mont(BN_ULONG *rp, const BN_ULONG *ap, const BN_ULONG *np,BN_ULONG n0, int num)
+       {
+       bn_mul_mont(rp,ap,ap,np,n0,num);
+       }
+#endif /* OPENSSL_BN_ASM_MONT */
+
+#endif /* !BN_MUL_COMBA */