/* $Id$ */
/*
 * Copyright (C) 1998-2002 RSA Security Inc. All rights reserved.
 *
 * This work contains proprietary information of RSA Security.
 * Distribution is limited to authorized licensees of RSA
 * Security. Any unauthorized reproduction, distribution or
 * modification of this work is strictly prohibited.
 *
 */

#include "bn_lcl.h"

#if !(defined(NO_SPLIT) &&  defined(SPLIT_FILE))
#ifdef NO_SPLIT
#define SPLIT_BN_2s_COMP
#define SPLIT_BN_MUL_REC_WORDS
#define SPLIT_BN_SQR_REC_WORDS
#endif /* NO_SPLIT */

#ifdef SPLIT_BN_2s_COMP
void bn_2s_comp(r,a,n)
BN_ULONG *r,*a;
int n;
	{
	BN_ULONG l;
	int i;

	for (i=0; i<n; i++)
		{
		l=a[i];
		l= ~l+1;
		r[i]=l;
		if (l != 0) break;
		}
#if 1
	for (i++; i<n; i++)
		{
		r[i]= ~a[i];
		}
#else
	for (i+=4; i<n; i+=4)
		{
		r[i-3]= ~a[i-3];
		r[i-2]= ~a[i-2];
		r[i-1]= ~a[i-1];
		r[i  ]= ~a[i  ];
		}
	for (i-=3; i<n; i++)
		{
		r[i]= ~a[i];
		}
#endif
	}
#endif

#ifdef SPLIT_BN_MUL_REC_WORDS
/* t needs to be 2*n words */
void bn_mul_rec_words(r,a,b,tt,rec)
BN_ULONG *r,*a,*b,*tt;
BN_REC *rec;
	{
	int n=rec->n;
	int n2=n/2;
	int c1,neg=0;


	if (rec->depth == 0)
		{
		/* t needs to have space for 4*n words
		 * The multiply needs to be a n2*n2 -> n
		 */
#ifndef NOPROTO
		void (PRE_CCONV CCONV *rmul)(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b);
#else
		void (PRE_CCONV CCONV *rmul)();
#endif
		rmul=rec->mul;

#ifdef _EXTRA_ARG_
                /* THIS IS WRONG - there is no extra int arg on the end */
		rmul(&(r[0]),&(a[0]),&(b[0]),n2);
		rmul(&(r[n]),&(a[n2]),&(b[n2]),n2);
#else
		rmul(&(r[0]),&(a[0]),&(b[0]));
		rmul(&(r[n]),&(a[n2]),&(b[n2]));
#endif

		if (bn_sub_words(&(tt[n+0]), &(a[0]),&(a[n2]),n2))
			{
			bn_2s_comp(&(tt[n+ 0]),&(tt[n+ 0]),n2);
			neg=1;
			}
		else
			neg=0;
		if (bn_sub_words(&(tt[n+n2]),&(b[n2]),&(b[0]),n2))
			{
			neg^=1;
			bn_2s_comp(&(tt[n+n2]),&(tt[n+n2]),n2);
			}

#ifdef _EXTRA_ARG_
		rmul(&(tt[0]),&(tt[n+0]),&(tt[n+n2]),n2);
#else
		rmul(&(tt[0]),&(tt[n+0]),&(tt[n+n2]));
#endif
		}
	else	/* Leaf node */
		{
		/* t has 4*n words taken per call.
		 * Since n is half the size per call, we need
		 * 6*n words for our current level and all sub levels
		 * The multiply needs to be a n2*n2 -> n
		 */
		rec->depth--;
		rec->n=n2;
		bn_mul_rec_words(&(r[0]), &(a[0]), &(b[0]),    &(tt[n+n]),rec);
		bn_mul_rec_words(&(r[n]), &(a[n2]),&(b[n2]),   &(tt[n+n]),rec);

		neg=0;
		if (bn_sub_words(&(tt[n+0]), &(a[0]),&(a[n2]),n2))
			{
			bn_2s_comp(&(tt[n+ 0]),&(tt[n+ 0]),n2);
			neg=1;
			}
		else
			neg=0;
		if (bn_sub_words(&(tt[n+n2]),&(b[n2]),&(b[0]),n2))
			{
			neg^=1;
			bn_2s_comp(&(tt[n+n2]),&(tt[n+n2]),n2);
			}

		bn_mul_rec_words(&(tt[0]),&(tt[n]),&(tt[n+n2]),&(tt[n+n]),rec);
		rec->n=n;
		rec->depth++;
		}

	c1=bn_add_words(&(tt[n]),&(r[0]),&(r[n]),n);

	if (neg)
		c1-=bn_sub_words(&(tt[0]),&(tt[n]),&(tt[0]),n);
	else
		c1+=bn_add_words(&(tt[0]),&(tt[n]),&(tt[0]),n);
	tt[n]=c1;
	c1=bn_add_words(&(r[n2]),&(r[n2]),&(tt[0]),n+1); 
	if (c1)
		{
		tt= &(r[n+n2+1]);
		do	{
			} while (++(*(tt++)) == 0);
		}
	}
#endif

#ifdef SPLIT_BN_SQR_REC_WORDS
/* tt needs to be 3*n words */
void bn_sqr_rec_words(r,a,tt,rec)
BN_ULONG *r,*a,*tt;
BN_REC *rec;
	{
	int n=rec->n;
	int n2=n/2;
	int c1;

	if (rec->depth == 0)
		{
		/* t needs to have space for 4*n words
		 * The multiply needs to be a n2*n2 -> n
		 */
#ifndef NOPROTO
		void (PRE_CCONV CCONV *rsqr)(BN_ULONG *r, BN_ULONG *a);
#else
		void (PRE_CCONV CCONV *rsqr)();
#endif

		rsqr=rec->sqr;

#ifdef _EXTRA_ARG_
                /* THIS IS WRONG - there is no extra int arg on the end */
		rsqr(&(r[0]), &(a[0]), n2);
		rsqr(&(r[n]), &(a[n2]),n2);
#else
		rsqr(&(r[0]), &(a[0]));
		rsqr(&(r[n]), &(a[n2]));
#endif

		if (bn_sub_words(&(tt[n+0]), &(a[0]),&(a[n2]),n2))
			bn_2s_comp(&(tt[n+0]),&tt[n+0], n2);

#ifdef _EXTRA_ARG_
		rsqr(&(tt[0]),&(tt[n]), n2);
#else
		rsqr(&(tt[0]),&(tt[n]));
#endif

		}
	else	/* Leaf node */
		{
		/* t has 4*n words taken per call.
		 * Since n is half the size per call, we need
		 * 6*n words for our current level and all sub levels
		 * The multiply needs to be a n2*n2 -> n
		 */
		rec->depth--;
		rec->n=n2;
		bn_sqr_rec_words(&(r[0]), &(a[0]), &(tt[n+n]),rec);
		bn_sqr_rec_words(&(r[n]), &(a[n2]),&(tt[n+n]),rec);

		if (bn_sub_words(&(tt[n+0]), &(a[0]),&(a[n2]),n2))
			bn_2s_comp(&(tt[n+0]),&tt[n+0], n2);
		bn_sqr_rec_words(&(tt[0]),&(tt[n]),&(tt[n+n]),rec);

		rec->n=n;
		rec->depth++;
		}

	c1=bn_add_words(&(tt[n]),&(r[0]),&(r[n]),n);
	c1-=bn_sub_words(&(tt[0]),&(tt[n]),&(tt[0]),n);

	tt[n]=c1;
	c1=bn_add_words(&(r[n2]),&(r[n2]),&(tt[0]),n+1); 
	if (c1)
		{
		tt= &(r[n+n2+1]);
		do	{
			} while (++(*(tt++)) == 0);
		}
	}
#endif

#endif /* !NO_SPLIT || !SPLIT_FILE */