curve448: Rename arch_ref64 to arch_64

[thirdparty/openssl.git] / crypto / ec / curve448 / arch_64 / f_impl.h

/*
 * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
 * Copyright 2014-2016 Cryptography Research, Inc.
 *
 * 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 Mike Hamburg
 */

#define GF_HEADROOM 9999        /* Everything is reduced anyway */
#define FIELD_LITERAL(a,b,c,d,e,f,g,h) {{a,b,c,d,e,f,g,h}}

#define LIMB_PLACE_VALUE(i) 56

void gf_add_RAW(gf out, const gf a, const gf b)
{
    for (unsigned int i = 0; i < 8; i++)
        out->limb[i] = a->limb[i] + b->limb[i];
    gf_weak_reduce(out);
}

void gf_sub_RAW(gf out, const gf a, const gf b)
{
    uint64_t co1 = ((1ull << 56) - 1) * 2, co2 = co1 - 2;

    for (unsigned int i = 0; i < 8; i++)
        out->limb[i] = a->limb[i] - b->limb[i] + ((i == 4) ? co2 : co1);
    gf_weak_reduce(out);
}

void gf_bias(gf a, int amt)
{
    (void)a;
    (void)amt;
}

void gf_weak_reduce(gf a)
{
    uint64_t mask = (1ull << 56) - 1;
    uint64_t tmp = a->limb[7] >> 56;

    a->limb[4] += tmp;
    for (unsigned int i = 7; i > 0; i--)
        a->limb[i] = (a->limb[i] & mask) + (a->limb[i - 1] >> 56);
    a->limb[0] = (a->limb[0] & mask) + tmp;
}