/* crypto/bn/bn_nist.c */

/*

 * Written by Nils Larsch for the OpenSSL project

 */

/* ====================================================================

 * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer. 

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    openssl-core@openssl.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 * ====================================================================

 *

 * This product includes cryptographic software written by Eric Young

 * (eay@cryptsoft.com).  This product includes software written by Tim

 * Hudson (tjh@cryptsoft.com).

 *

 */

 /*

 © Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 */

#include "bn_lcl.h"

#include "cryptlib.h"

#if (defined(SYMBIAN) && (defined(__WINSCW__) || defined(__WINS__)))

#include "libcrypto_wsd_macros.h"

#include "libcrypto_wsd.h"

#endif

#define BN_NIST_192_TOP	(192+BN_BITS2-1)/BN_BITS2

#define BN_NIST_224_TOP	(224+BN_BITS2-1)/BN_BITS2

#define BN_NIST_256_TOP	(256+BN_BITS2-1)/BN_BITS2

#define BN_NIST_384_TOP	(384+BN_BITS2-1)/BN_BITS2

#define BN_NIST_521_TOP	(521+BN_BITS2-1)/BN_BITS2

#if BN_BITS2 == 64

static const BN_ULONG _nist_p_192[] =

	{0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFEULL,

	0xFFFFFFFFFFFFFFFFULL};

static const BN_ULONG _nist_p_224[] =

	{0x0000000000000001ULL,0xFFFFFFFF00000000ULL,

	0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL};

static const BN_ULONG _nist_p_256[] =

	{0xFFFFFFFFFFFFFFFFULL,0x00000000FFFFFFFFULL,

	0x0000000000000000ULL,0xFFFFFFFF00000001ULL};

static const BN_ULONG _nist_p_384[] =

	{0x00000000FFFFFFFFULL,0xFFFFFFFF00000000ULL,

	0xFFFFFFFFFFFFFFFEULL,0xFFFFFFFFFFFFFFFFULL,

	0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL};

static const BN_ULONG _nist_p_521[] =

	{0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,

	0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,

	0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,

	0xFFFFFFFFFFFFFFFFULL,0xFFFFFFFFFFFFFFFFULL,

	0x00000000000001FFULL};

#elif BN_BITS2 == 32

static const BN_ULONG _nist_p_192[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFE,

	0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};

static const BN_ULONG _nist_p_224[] = {0x00000001,0x00000000,0x00000000,

	0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};

static const BN_ULONG _nist_p_256[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,

	0x00000000,0x00000000,0x00000000,0x00000001,0xFFFFFFFF};

static const BN_ULONG _nist_p_384[] = {0xFFFFFFFF,0x00000000,0x00000000,

	0xFFFFFFFF,0xFFFFFFFE,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,

	0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF};

static const BN_ULONG _nist_p_521[] = {0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,

	0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,

	0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,0xFFFFFFFF,

	0xFFFFFFFF,0x000001FF};

#elif BN_BITS2 == 16

static const BN_ULONG _nist_p_192[] = {0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFE,

	0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF};

static const BN_ULONG _nist_p_224[] = {0x0001,0x0000,0x0000,0x0000,0x0000,

	0x0000,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF};

static const BN_ULONG _nist_p_256[] = {0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,

	0xFFFF,0x0000,0x0000,0x0000,0x0000,0x0000,0x0000,0x0001,0x0000,0xFFFF,

	0xFFFF};

static const BN_ULONG _nist_p_384[] = {0xFFFF,0xFFFF,0x0000,0x0000,0x0000,

	0x0000,0xFFFF,0xFFFF,0xFFFE,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,

	0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF};

static const BN_ULONG _nist_p_521[] = {0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,

	0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,

	0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,

	0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0xFFFF,0x01FF};

#elif BN_BITS2 == 8

static const BN_ULONG _nist_p_192[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFE,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF};

static const BN_ULONG _nist_p_224[] = {0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00,

	0x00,0x00,0x00,0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};

static const BN_ULONG _nist_p_256[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,

	0x00,0x00,0x01,0x00,0x00,0x00,0xFF,0xFF,0xFF,0xFF};

static const BN_ULONG _nist_p_384[] = {0xFF,0xFF,0xFF,0xFF,0x00,0x00,0x00,0x00,

	0x00,0x00,0x00,0x00,0xFF,0xFF,0xFF,0xFF,0xFE,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};

static const BN_ULONG _nist_p_521[] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,

	0xFF,0x01};

#endif

EXPORT_C const BIGNUM *BN_get0_nist_prime_192(void)

	{

#ifndef EMULATOR	

	static BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192,

		BN_NIST_192_TOP, BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA };

#else

	static const BIGNUM const_nist_192 = { (BN_ULONG *)_nist_p_192,

		BN_NIST_192_TOP, BN_NIST_192_TOP, 0, BN_FLG_STATIC_DATA };

#endif	

	return &const_nist_192;

	}

EXPORT_C const BIGNUM *BN_get0_nist_prime_224(void)

	{

#ifndef EMULATOR		

	static BIGNUM const_nist_224 = { (BN_ULONG *)_nist_p_224,

		BN_NIST_224_TOP, BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA };

#else

    static const  BIGNUM const_nist_224 = { (BN_ULONG *)_nist_p_224,

		BN_NIST_224_TOP, BN_NIST_224_TOP, 0, BN_FLG_STATIC_DATA };

#endif		

	return &const_nist_224;

	}

EXPORT_C const BIGNUM *BN_get0_nist_prime_256(void)

	{

#ifndef EMULATOR		

	static BIGNUM const_nist_256 = { (BN_ULONG *)_nist_p_256,

		BN_NIST_256_TOP, BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA };

#else		

    static const BIGNUM const_nist_256 = { (BN_ULONG *)_nist_p_256,

		BN_NIST_256_TOP, BN_NIST_256_TOP, 0, BN_FLG_STATIC_DATA };

#endif		

	return &const_nist_256;

	}

EXPORT_C const BIGNUM *BN_get0_nist_prime_384(void)

	{

#ifndef EMULATOR		

	static BIGNUM const_nist_384 = { (BN_ULONG *)_nist_p_384,

		BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };

#else

    static const BIGNUM const_nist_384 = { (BN_ULONG *)_nist_p_384,

		BN_NIST_384_TOP, BN_NIST_384_TOP, 0, BN_FLG_STATIC_DATA };

#endif		

	return &const_nist_384;

	}

EXPORT_C const BIGNUM *BN_get0_nist_prime_521(void)

	{

#ifndef EMULATOR		

	static BIGNUM const_nist_521 = { (BN_ULONG *)_nist_p_521,

		BN_NIST_521_TOP, BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA };

#else

	static const BIGNUM const_nist_521 = { (BN_ULONG *)_nist_p_521,

		BN_NIST_521_TOP, BN_NIST_521_TOP, 0, BN_FLG_STATIC_DATA };

#endif		

	return &const_nist_521;

	}

/* some misc internal functions */

#if BN_BITS2 != 64

#ifndef EMULATOR

static BN_ULONG _256_data[BN_NIST_256_TOP*6];

static int _is_set_256_data = 0;

static void _init_256_data(void);

static BN_ULONG _384_data[BN_NIST_384_TOP*8];

static int _is_set_384_data = 0;

static void _init_384_data(void);

#else

GET_STATIC_ARRAY_FROM_TLS(_256_data,bn_nist,BN_ULONG)

#define _256_data (GET_WSD_VAR_NAME(_256_data,bn_nist, s)())

GET_STATIC_VAR_FROM_TLS(_is_set_256_data,bn_nist,int)

#define _is_set_256_data (*GET_WSD_VAR_NAME(_is_set_256_data,bn_nist, s)())

GET_STATIC_ARRAY_FROM_TLS(_384_data,bn_nist,BN_ULONG)

#define _384_data (GET_WSD_VAR_NAME(_384_data,bn_nist, s)())

GET_STATIC_VAR_FROM_TLS(_is_set_384_data,bn_nist,int)

#define _is_set_384_data (*GET_WSD_VAR_NAME(_is_set_384_data,bn_nist, s)())

#endif

#endif

#define BN_NIST_ADD_ONE(a)	while (!(++(*(a)))) ++(a);

static void nist_cp_bn_0(BN_ULONG *buf, BN_ULONG *a, int top, int max)

        {

	int i;

        BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);

        for (i = (top); i != 0; i--)

                *_tmp1++ = *_tmp2++;

        for (i = (max) - (top); i != 0; i--)

                *_tmp1++ = (BN_ULONG) 0;

        }

static void nist_cp_bn(BN_ULONG *buf, BN_ULONG *a, int top)

        { 

	int i;

        BN_ULONG *_tmp1 = (buf), *_tmp2 = (a);

        for (i = (top); i != 0; i--)

                *_tmp1++ = *_tmp2++;

        }

#if BN_BITS2 == 64

#define bn_cp_64(to, n, from, m)	(to)[n] = (from)[m];

#define bn_64_set_0(to, n)		(to)[n] = (BN_ULONG)0;

/* TBD */

#define bn_cp_32(to, n, from, m)	(to)[n] = (from)[m];

#define bn_32_set_0(to, n)		(to)[n] = (BN_ULONG)0;

#else

#define bn_cp_64(to, n, from, m) \

	{ \

	bn_cp_32(to, (n)*2, from, (m)*2); \

	bn_cp_32(to, (n)*2+1, from, (m)*2+1); \

	}

#define bn_64_set_0(to, n) \

	{ \

	bn_32_set_0(to, (n)*2); \

	bn_32_set_0(to, (n)*2+1); \

	}

#if BN_BITS2 == 32

#define bn_cp_32(to, n, from, m)	(to)[n] = (from)[m];

#define bn_32_set_0(to, n)		(to)[n] = (BN_ULONG)0;

#elif BN_BITS2 == 16

#define bn_cp_32(to, n, from, m) \

	{ \

	(to)[(n)*2]   = (from)[(m)*2];  \

	(to)[(n)*2+1] = (from)[(m)*2+1];\

	}

#define bn_32_set_0(to, n) { (to)[(n)*2] = 0; (to)[(n)*2+1] = 0; }

#elif BN_BITS2 == 8

#define bn_cp_32(to, n, from, m) \

	{ \

	(to)[(n)*4]   = (from)[(m)*4];  \

	(to)[(n)*4+1] = (from)[(m)*4+1];\

	(to)[(n)*4+2] = (from)[(m)*4+2];\

	(to)[(n)*4+3] = (from)[(m)*4+3];\

	}

#define bn_32_set_0(to, n) \

	{ (to)[(n)*4]   = (BN_ULONG)0; (to)[(n)*4+1] = (BN_ULONG)0; \

	  (to)[(n)*4+2] = (BN_ULONG)0; (to)[(n)*4+3] = (BN_ULONG)0; }

#endif

#endif /* BN_BITS2 != 64 */

#define nist_set_192(to, from, a1, a2, a3) \

	{ \

	if (a3 != 0) bn_cp_64(to, 0, from, (a3) - 3) else bn_64_set_0(to, 0)\

	bn_cp_64(to, 1, from, (a2) - 3) \

	if (a1 != 0) bn_cp_64(to, 2, from, (a1) - 3) else bn_64_set_0(to, 2)\

	}

EXPORT_C int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,

	BN_CTX *ctx)

	{

	int      top = a->top, i;

	BN_ULONG carry = 0;

	register BN_ULONG *r_d, *a_d = a->d;

	BN_ULONG t_d[BN_NIST_192_TOP],

	         buf[BN_NIST_192_TOP];

	i = BN_ucmp(field, a);

	if (i == 0)

		{

		BN_zero(r);

		return 1;

		}

	else if (i > 0)

		return (r == a) ? 1 : (BN_copy(r ,a) != NULL);

	if (top == BN_NIST_192_TOP)

		return BN_usub(r, a, field);

	if (r != a)

		{

		if (!bn_wexpand(r, BN_NIST_192_TOP))

			return 0;

		r_d = r->d;

		nist_cp_bn(r_d, a_d, BN_NIST_192_TOP);

		}

	else

		r_d = a_d;

	nist_cp_bn_0(buf, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP, BN_NIST_192_TOP);

#if defined(OPENSSL_SYS_VMS) && defined(__DECC)

# pragma message save

# pragma message disable BADSUBSCRIPT

#endif

	nist_set_192(t_d, buf, 0, 3, 3);

	if (bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP))

		++carry;

	nist_set_192(t_d, buf, 4, 4, 0);

	if (bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP))

		++carry;

#if defined(OPENSSL_SYS_VMS) && defined(__DECC)

# pragma message restore

#endif

	nist_set_192(t_d, buf, 5, 5, 5)

	if (bn_add_words(r_d, r_d, t_d, BN_NIST_192_TOP))

		++carry;

	while (carry)

		{

		if (bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP))

			--carry; 

		}

	r->top = BN_NIST_192_TOP;

	bn_correct_top(r);

	if (BN_ucmp(r, field) >= 0)

		{

		bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP);

		bn_correct_top(r);

		}

	bn_check_top(r);

	return 1;

	}

#define nist_set_224(to, from, a1, a2, a3, a4, a5, a6, a7) \

	{ \

	if (a7 != 0) bn_cp_32(to, 0, from, (a7) - 7) else bn_32_set_0(to, 0)\

	if (a6 != 0) bn_cp_32(to, 1, from, (a6) - 7) else bn_32_set_0(to, 1)\

	if (a5 != 0) bn_cp_32(to, 2, from, (a5) - 7) else bn_32_set_0(to, 2)\

	if (a4 != 0) bn_cp_32(to, 3, from, (a4) - 7) else bn_32_set_0(to, 3)\

	if (a3 != 0) bn_cp_32(to, 4, from, (a3) - 7) else bn_32_set_0(to, 4)\

	if (a2 != 0) bn_cp_32(to, 5, from, (a2) - 7) else bn_32_set_0(to, 5)\

	if (a1 != 0) bn_cp_32(to, 6, from, (a1) - 7) else bn_32_set_0(to, 6)\

	}

EXPORT_C int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,

	BN_CTX *ctx)

	{

#if BN_BITS2 != 64

	int	top = a->top, i;

	int	carry = 0;

	BN_ULONG *r_d, *a_d = a->d;

	BN_ULONG t_d[BN_NIST_224_TOP],

	         buf[BN_NIST_224_TOP];

	i = BN_ucmp(field, a);

	if (i == 0)

		{

		BN_zero(r);

		return 1;

		}

	else if (i > 0)

		return (r == a)? 1 : (BN_copy(r ,a) != NULL);

	if (top == BN_NIST_224_TOP)

		return BN_usub(r, a, field);

	if (r != a)

		{

		if (!bn_wexpand(r, BN_NIST_224_TOP))

			return 0;

		r_d = r->d;

		nist_cp_bn(r_d, a_d, BN_NIST_224_TOP);

		}

	else

		r_d = a_d;

	nist_cp_bn_0(buf, a_d + BN_NIST_224_TOP, top - BN_NIST_224_TOP, BN_NIST_224_TOP);

	nist_set_224(t_d, buf, 10, 9, 8, 7, 0, 0, 0);

	if (bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP))

		++carry;

	nist_set_224(t_d, buf, 0, 13, 12, 11, 0, 0, 0);

	if (bn_add_words(r_d, r_d, t_d, BN_NIST_224_TOP))

		++carry;

	nist_set_224(t_d, buf, 13, 12, 11, 10, 9, 8, 7);

	if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP))

		--carry;

	nist_set_224(t_d, buf, 0, 0, 0, 0, 13, 12, 11);

	if (bn_sub_words(r_d, r_d, t_d, BN_NIST_224_TOP))

		--carry;

	if (carry > 0)

		while (carry)

			{

			if (bn_sub_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP))

				--carry;

			}

	else if (carry < 0)

		while (carry)

			{

			if (bn_add_words(r_d,r_d,_nist_p_224,BN_NIST_224_TOP))

				++carry;

			}

	r->top = BN_NIST_224_TOP;

	bn_correct_top(r);

	if (BN_ucmp(r, field) >= 0)

		{

		bn_sub_words(r_d, r_d, _nist_p_224, BN_NIST_224_TOP);

		bn_correct_top(r);

		}

	bn_check_top(r);

	return 1;

#else

	return 0;

#endif

	}

#if BN_BITS2 != 64

static void _init_256_data(void)

	{

	int	i;

	BN_ULONG *tmp1 = _256_data;

	const BN_ULONG *tmp2 = tmp1;

	memcpy(tmp1, _nist_p_256, BN_NIST_256_TOP * sizeof(BN_ULONG));

	tmp1 += BN_NIST_256_TOP;

	for (i=0; i<5; i++)

		{

		bn_add_words(tmp1, _nist_p_256, tmp2, BN_NIST_256_TOP);

		tmp2  = tmp1;

		tmp1 += BN_NIST_256_TOP;

		}

	_is_set_256_data = 1;

	}

#endif

#define nist_set_256(to, from, a1, a2, a3, a4, a5, a6, a7, a8) \

	{ \

	if (a8 != 0) bn_cp_32(to, 0, from, (a8) - 8) else bn_32_set_0(to, 0)\

	if (a7 != 0) bn_cp_32(to, 1, from, (a7) - 8) else bn_32_set_0(to, 1)\

	if (a6 != 0) bn_cp_32(to, 2, from, (a6) - 8) else bn_32_set_0(to, 2)\

	if (a5 != 0) bn_cp_32(to, 3, from, (a5) - 8) else bn_32_set_0(to, 3)\

	if (a4 != 0) bn_cp_32(to, 4, from, (a4) - 8) else bn_32_set_0(to, 4)\

	if (a3 != 0) bn_cp_32(to, 5, from, (a3) - 8) else bn_32_set_0(to, 5)\

	if (a2 != 0) bn_cp_32(to, 6, from, (a2) - 8) else bn_32_set_0(to, 6)\

	if (a1 != 0) bn_cp_32(to, 7, from, (a1) - 8) else bn_32_set_0(to, 7)\

	}

EXPORT_C int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,

	BN_CTX *ctx)

	{

#if BN_BITS2 != 64

	int	i, top = a->top;

	int	carry = 0;

	register BN_ULONG *a_d = a->d, *r_d;

	BN_ULONG t_d[BN_NIST_256_TOP],

	         t_d2[BN_NIST_256_TOP],

	         buf[BN_NIST_256_TOP];

	if (!_is_set_256_data)

		{

		CRYPTO_w_lock(CRYPTO_LOCK_BN);

		if (!_is_set_256_data)

			_init_256_data();

		CRYPTO_w_unlock(CRYPTO_LOCK_BN);

		}

	i = BN_ucmp(field, a);

	if (i == 0)

		{

		BN_zero(r);

		return 1;

		}

	else if (i > 0)

		return (r == a)? 1 : (BN_copy(r ,a) != NULL);