static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
	{
	BIGNUM *n;
	BN_ULONG *ap,*np,*rp,n0,v,*nrp;
	int al,nl,max,i,x,ri;

	n= &(mont->N);
	/* mont->ri is the size of mont->N in bits (rounded up
	   to the word size) */
	al=ri=mont->ri/BN_BITS2;

	nl=n->top;
	if ((al == 0) || (nl == 0)) { ret->top=0; return(1); }

	max=(nl+al+1); /* allow for overflow (no?) XXX */
	if (bn_wexpand(r,max) == NULL) return(0);

	r->neg^=n->neg;
	np=n->d;
	rp=r->d;
	nrp= &(r->d[nl]);

	/* clear the top words of T */
#if 1
	for (i=r->top; i<max; i++) /* memset? XXX */
		r->d[i]=0;
#else
	memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG)); 
#endif

	r->top=max;
	n0=mont->n0[0];

#ifdef BN_COUNT
	fprintf(stderr,"word BN_from_montgomery_word %d * %d\n",nl,nl);
#endif
	for (i=0; i<nl; i++)
		{
#ifdef __TANDEM
                {
                   long long t1;
                   long long t2;
                   long long t3;
                   t1 = rp[0] * (n0 & 0177777);
                   t2 = 037777600000l;
                   t2 = n0 & t2;
                   t3 = rp[0] & 0177777;
                   t2 = (t3 * t2) & BN_MASK2;
                   t1 = t1 + t2;
                   v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
                }
#else
		v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
#endif
		nrp++;
		rp++;
		if (((nrp[-1]+=v)&BN_MASK2) >= v)
			continue;
		else
			{
			if (((++nrp[0])&BN_MASK2) != 0) continue;
			if (((++nrp[1])&BN_MASK2) != 0) continue;
			for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
			}
		}
	bn_correct_top(r);
	
	/* mont->ri will be a multiple of the word size */
#if 0
	BN_rshift(ret,r,mont->ri);
#else
	if (r->top < ri)
		{
		ret->top=0;
		return(1);
		}
	al=r->top-ri;
	if (bn_wexpand(ret,al) == NULL) return(0);
	ret->neg=r->neg;
	ret->top=al;

	rp=ret->d;
	ap=&(r->d[ri]);
	al-=4;
	for (i=0; i<al; i+=4)
		{
		BN_ULONG t1,t2,t3,t4;
		
		t1=ap[i+0];
		t2=ap[i+1];
		t3=ap[i+2];
		t4=ap[i+3];
		rp[i+0]=t1;
		rp[i+1]=t2;
		rp[i+2]=t3;
		rp[i+3]=t4;
		}
	al+=4;
	for (; i<al; i++)
		rp[i]=ap[i];
#endif

	if (BN_ucmp(ret, &(mont->N)) >= 0)
		{
		if (!BN_usub(ret,ret,&(mont->N))) return(0);
		}
	bn_check_top(ret);

	return(1);
	}