1 /*
2 * Copyright 2017-2022 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright 2014-2016 Cryptography Research, Inc.
4 *
5 * Licensed under the Apache License 2.0 (the "License"). You may not use
6 * this file except in compliance with the License. You can obtain a copy
7 * in the file LICENSE in the source distribution or at
8 * https://www.openssl.org/source/license.html
9 *
10 * Originally written by Mike Hamburg
11 */
12
13 #ifndef OSSL_CRYPTO_EC_CURVE448_ARCH_64_F_IMPL_H
14 # define OSSL_CRYPTO_EC_CURVE448_ARCH_64_F_IMPL_H
15
16 # define GF_HEADROOM 9999 /* Everything is reduced anyway */
17 # define FIELD_LITERAL(a,b,c,d,e,f,g,h) {{a,b,c,d,e,f,g,h}}
18
19 # define LIMB_PLACE_VALUE(i) 56
20
gf_add_RAW(gf out,const gf a,const gf b)21 void gf_add_RAW(gf out, const gf a, const gf b)
22 {
23 unsigned int i;
24
25 for (i = 0; i < NLIMBS; i++)
26 out->limb[i] = a->limb[i] + b->limb[i];
27
28 gf_weak_reduce(out);
29 }
30
gf_sub_RAW(gf out,const gf a,const gf b)31 void gf_sub_RAW(gf out, const gf a, const gf b)
32 {
33 uint64_t co1 = ((1ULL << 56) - 1) * 2, co2 = co1 - 2;
34 unsigned int i;
35
36 for (i = 0; i < NLIMBS; i++)
37 out->limb[i] = a->limb[i] - b->limb[i] + ((i == NLIMBS / 2) ? co2 : co1);
38
39 gf_weak_reduce(out);
40 }
41
gf_bias(gf a,int amt)42 void gf_bias(gf a, int amt)
43 {
44 }
45
gf_weak_reduce(gf a)46 void gf_weak_reduce(gf a)
47 {
48 uint64_t mask = (1ULL << 56) - 1;
49 uint64_t tmp = a->limb[NLIMBS - 1] >> 56;
50 unsigned int i;
51
52 a->limb[NLIMBS / 2] += tmp;
53 for (i = NLIMBS - 1; i > 0; i--)
54 a->limb[i] = (a->limb[i] & mask) + (a->limb[i - 1] >> 56);
55 a->limb[0] = (a->limb[0] & mask) + tmp;
56 }
57
58 #endif /* OSSL_CRYPTO_EC_CURVE448_ARCH_64_F_IMPL_H */
59