crypto/ec/curve448/arch_32/f_impl32.c

   1 /*
   2  * Copyright 2017-2021 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright 2014 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 #include "e_os.h"
  14 #include "openssl/macros.h"
  15 #include "internal/numbers.h"
  16
  17 #ifdef UINT128_MAX
  18 /* We have support for 128 bit ints, so do nothing here */
  19 NON_EMPTY_TRANSLATION_UNIT
  20 #else
  21
  22 # include "../field.h"
  23
  24 void gf_mul(gf_s * RESTRICT cs, const gf as, const gf bs)
  25 {
  26     const uint32_t *a = as->limb, *b = bs->limb;
  27     uint32_t *c = cs->limb;
  28     uint64_t accum0 = 0, accum1 = 0, accum2 = 0;
  29     uint32_t mask = (1 << 28) - 1;
  30     uint32_t aa[8], bb[8];
  31     int i, j;
  32
  33     for (i = 0; i < 8; i++) {
  34         aa[i] = a[i] + a[i + 8];
  35         bb[i] = b[i] + b[i + 8];
  36     }
  37
  38     for (j = 0; j < 8; j++) {
  39         accum2 = 0;
  40         for (i = 0; i < j + 1; i++) {
  41             accum2 += widemul(a[j - i], b[i]);
  42             accum1 += widemul(aa[j - i], bb[i]);
  43             accum0 += widemul(a[8 + j - i], b[8 + i]);
  44         }
  45         accum1 -= accum2;
  46         accum0 += accum2;
  47         accum2 = 0;
  48         for (i = j + 1; i < 8; i++) {
  49             accum0 -= widemul(a[8 + j - i], b[i]);
  50             accum2 += widemul(aa[8 + j - i], bb[i]);
  51             accum1 += widemul(a[16 + j - i], b[8 + i]);
  52         }
  53         accum1 += accum2;
  54         accum0 += accum2;
  55         c[j] = ((uint32_t)(accum0)) & mask;
  56         c[j + 8] = ((uint32_t)(accum1)) & mask;
  57         accum0 >>= 28;
  58         accum1 >>= 28;
  59     }
  60
  61     accum0 += accum1;
  62     accum0 += c[8];
  63     accum1 += c[0];
  64     c[8] = ((uint32_t)(accum0)) & mask;
  65     c[0] = ((uint32_t)(accum1)) & mask;
  66
  67     accum0 >>= 28;
  68     accum1 >>= 28;
  69     c[9] += ((uint32_t)(accum0));
  70     c[1] += ((uint32_t)(accum1));
  71 }
  72
  73 void gf_mulw_unsigned(gf_s * RESTRICT cs, const gf as, uint32_t b)
  74 {
  75     const uint32_t *a = as->limb;
  76     uint32_t *c = cs->limb;
  77     uint64_t accum0 = 0, accum8 = 0;
  78     uint32_t mask = (1 << 28) - 1;
  79     int i;
  80
  81     assert(b <= mask);
  82
  83     for (i = 0; i < 8; i++) {
  84         accum0 += widemul(b, a[i]);
  85         accum8 += widemul(b, a[i + 8]);
  86         c[i] = accum0 & mask;
  87         accum0 >>= 28;
  88         c[i + 8] = accum8 & mask;
  89         accum8 >>= 28;
  90     }
  91
  92     accum0 += accum8 + c[8];
  93     c[8] = ((uint32_t)accum0) & mask;
  94     c[9] += (uint32_t)(accum0 >> 28);
  95
  96     accum8 += c[0];
  97     c[0] = ((uint32_t)accum8) & mask;
  98     c[1] += (uint32_t)(accum8 >> 28);
  99 }
 100
 101 void gf_sqr(gf_s * RESTRICT cs, const gf as)
 102 {
 103     gf_mul(cs, as, as);         /* Performs better with a dedicated square */
 104 }
 105 #endif