/*
 * Copyright 2014-2016 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright (c) 2014, Intel Corporation. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (the "License").  You may not use
 * this file except in compliance with the License.  You can obtain a copy
 * in the file LICENSE in the source distribution or at
 * https://www.openssl.org/source/license.html
 *
 * Originally written by Shay Gueron (1, 2), and Vlad Krasnov (1)
 * (1) Intel Corporation, Israel Development Center, Haifa, Israel
 * (2) University of Haifa, Israel
 *
 * Reference:
 * S.Gueron and V.Krasnov, "Fast Prime Field Elliptic Curve Cryptography with
 *                          256 Bit Primes"
 */

#ifndef OPENSSL_HEADER_EC_P256_X86_64_H
#define OPENSSL_HEADER_EC_P256_X86_64_H

#include <ring-core/base.h>

#include "p256_shared.h"

#include "../bn/internal.h"

#if defined(OPENSSL_USE_NISTZ256)

// ecp_nistz256_neg sets |res| to -|a| mod P.
void ecp_nistz256_neg(BN_ULONG res[P256_LIMBS], const BN_ULONG a[P256_LIMBS]);

// ecp_nistz256_mul_mont sets |res| to |a| * |b| * 2^-256 mod P.
void ecp_nistz256_mul_mont(BN_ULONG res[P256_LIMBS],
                           const BN_ULONG a[P256_LIMBS],
                           const BN_ULONG b[P256_LIMBS]);

// ecp_nistz256_sqr_mont sets |res| to |a| * |a| * 2^-256 mod P.
void ecp_nistz256_sqr_mont(BN_ULONG res[P256_LIMBS],
                           const BN_ULONG a[P256_LIMBS]);


// P-256 scalar operations.
//
// The following functions compute modulo N, where N is the order of P-256. They
// take fully-reduced inputs and give fully-reduced outputs.

// ecp_nistz256_ord_mul_mont sets |res| to |a| * |b| where inputs and outputs
// are in Montgomery form. That is, |res| is |a| * |b| * 2^-256 mod N.
void ecp_nistz256_ord_mul_mont(BN_ULONG res[P256_LIMBS],
                               const BN_ULONG a[P256_LIMBS],
                               const BN_ULONG b[P256_LIMBS]);

// ecp_nistz256_ord_sqr_mont sets |res| to |a|^(2*|rep|) where inputs and
// outputs are in Montgomery form. That is, |res| is
// (|a| * 2^-256)^(2*|rep|) * 2^256 mod N.
void ecp_nistz256_ord_sqr_mont(BN_ULONG res[P256_LIMBS],
                               const BN_ULONG a[P256_LIMBS], BN_ULONG rep);



// P-256 point operations.
//
// The following functions may be used in-place. All coordinates are in the
// Montgomery domain.

// A P256_POINT_AFFINE represents a P-256 point in affine coordinates. Infinity
// is encoded as (0, 0).
typedef struct {
  BN_ULONG X[P256_LIMBS];
  BN_ULONG Y[P256_LIMBS];
} P256_POINT_AFFINE;

// ecp_nistz256_select_w5 sets |*val| to |in_t[index-1]| if 1 <= |index| <= 16
// and all zeros (the point at infinity) if |index| is 0. This is done in
// constant time.
void ecp_nistz256_select_w5(P256_POINT *val, const P256_POINT in_t[16],
                            int index);

// ecp_nistz256_select_w7 sets |*val| to |in_t[index-1]| if 1 <= |index| <= 64
// and all zeros (the point at infinity) if |index| is 0. This is done in
// constant time.
void ecp_nistz256_select_w7(P256_POINT_AFFINE *val,
                            const P256_POINT_AFFINE in_t[64],
                            int index);

// ecp_nistz256_point_double sets |r| to |a| doubled.
void ecp_nistz256_point_double(P256_POINT *r, const P256_POINT *a);

// ecp_nistz256_point_add adds |a| to |b| and places the result in |r|.
void ecp_nistz256_point_add(P256_POINT *r, const P256_POINT *a,
                            const P256_POINT *b);

// ecp_nistz256_point_add_affine adds |a| to |b| and places the result in
// |r|. |a| and |b| must not represent the same point unless they are both
// infinity.
void ecp_nistz256_point_add_affine(P256_POINT *r, const P256_POINT *a,
                                   const P256_POINT_AFFINE *b);

#endif /* defined(OPENSSL_USE_NISTZ256) */

#endif  // OPENSSL_HEADER_EC_P256_X86_64_H
