crypto/ec/curve448/arch_32/f_impl.h

   1 /*
   2  * Copyright 2017-2018 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 HEADER_ARCH_32_F_IMPL_H
  14 # define HEADER_ARCH_32_F_IMPL_H
  15
  16 # define GF_HEADROOM 2
  17 # define LIMB(x) ((x) & ((1 << 28) - 1)), ((x) >> 28)
  18 # define FIELD_LITERAL(a, b, c, d, e, f, g, h) \
  19     {{LIMB(a), LIMB(b), LIMB(c), LIMB(d), LIMB(e), LIMB(f), LIMB(g), LIMB(h)}}
  20
  21 # define LIMB_PLACE_VALUE(i) 28
  22
  23 void gf_add_RAW(gf out, const gf a, const gf b)
  24 {
  25     unsigned int i;
  26
  27     for (i = 0; i < NLIMBS; i++)
  28         out->limb[i] = a->limb[i] + b->limb[i];
  29 }
  30
  31 void gf_sub_RAW(gf out, const gf a, const gf b)
  32 {
  33     unsigned int i;
  34
  35     for (i = 0; i < NLIMBS; i++)
  36         out->limb[i] = a->limb[i] - b->limb[i];
  37 }
  38
  39 void gf_bias(gf a, int amt)
  40 {
  41     unsigned int i;
  42     uint32_t co1 = ((1 << 28) - 1) * amt, co2 = co1 - amt;
  43
  44     for (i = 0; i < NLIMBS; i++)
  45         a->limb[i] += (i == NLIMBS / 2) ? co2 : co1;
  46 }
  47
  48 void gf_weak_reduce(gf a)
  49 {
  50     uint32_t mask = (1 << 28) - 1;
  51     uint32_t tmp = a->limb[NLIMBS - 1] >> 28;
  52     unsigned int i;
  53
  54     a->limb[NLIMBS / 2] += tmp;
  55     for (i = NLIMBS - 1; i > 0; i--)
  56         a->limb[i] = (a->limb[i] & mask) + (a->limb[i - 1] >> 28);
  57     a->limb[0] = (a->limb[0] & mask) + tmp;
  58 }
  59
  60 #endif                  /* HEADER_ARCH_32_F_IMPL_H */