crypto/ec/curve448/word.h

   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 #ifndef OSSL_CRYPTO_EC_CURVE448_WORD_H
  14 # define OSSL_CRYPTO_EC_CURVE448_WORD_H
  15
  16 # include <string.h>
  17 # include <assert.h>
  18 # include <stdlib.h>
  19 # include <openssl/e_os2.h>
  20 # include "curve448utils.h"
  21
  22 # ifdef INT128_MAX
  23 #  include "arch_64/arch_intrinsics.h"
  24 # else
  25 #  include "arch_32/arch_intrinsics.h"
  26 # endif
  27
  28 # if (ARCH_WORD_BITS == 64)
  29 typedef uint64_t word_t, mask_t;
  30 typedef uint128_t dword_t;
  31 typedef int32_t hsword_t;
  32 typedef int64_t sword_t;
  33 typedef int128_t dsword_t;
  34 # elif (ARCH_WORD_BITS == 32)
  35 typedef uint32_t word_t, mask_t;
  36 typedef uint64_t dword_t;
  37 typedef int16_t hsword_t;
  38 typedef int32_t sword_t;
  39 typedef int64_t dsword_t;
  40 # else
  41 #  error "For now, we only support 32- and 64-bit architectures."
  42 # endif
  43
  44 /*
  45  * Scalar limbs are keyed off of the API word size instead of the arch word
  46  * size.
  47  */
  48 # if C448_WORD_BITS == 64
  49 #  define SC_LIMB(x) (x)
  50 # elif C448_WORD_BITS == 32
  51 #  define SC_LIMB(x) ((uint32_t)(x)),((x) >> 32)
  52 # else
  53 #  error "For now we only support 32- and 64-bit architectures."
  54 # endif
  55
  56 /*
  57  * The plan on booleans: The external interface uses c448_bool_t, but this
  58  * might be a different size than our particular arch's word_t (and thus
  59  * mask_t).  Also, the caller isn't guaranteed to pass it as nonzero.  So
  60  * bool_to_mask converts word sizes and checks nonzero. On the flip side,
  61  * mask_t is always -1 or 0, but it might be a different size than
  62  * c448_bool_t. On the third hand, we have success vs boolean types, but
  63  * that's handled in common.h: it converts between c448_bool_t and
  64  * c448_error_t.
  65  */
  66 static ossl_inline c448_bool_t mask_to_bool(mask_t m)
  67 {
  68     return (c448_sword_t)(sword_t)m;
  69 }
  70
  71 static ossl_inline mask_t bool_to_mask(c448_bool_t m)
  72 {
  73     /* On most arches this will be optimized to a simple cast. */
  74     mask_t ret = 0;
  75     unsigned int i;
  76     unsigned int limit = sizeof(c448_bool_t) / sizeof(mask_t);
  77
  78     if (limit < 1)
  79         limit = 1;
  80     for (i = 0; i < limit; i++)
  81         ret |= ~word_is_zero(m >> (i * 8 * sizeof(word_t)));
  82
  83     return ret;
  84 }
  85
  86 #endif                          /* OSSL_CRYPTO_EC_CURVE448_WORD_H */