ceph/src/boost/libs/config/test/boost_has_int128.ipp

   1 //  (C) Copyright John Maddock 2012.
   2 //  (C) Copyright Dynatrace 2017.
   3 //  Use, modification and distribution are subject to the
   4 //  Boost Software License, Version 1.0. (See accompanying file
   5 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6
   7 //  See http://www.boost.org/libs/config for most recent version.
   8
   9 //  MACRO:         BOOST_HAS_INT128
  10 //  TITLE:         __int128
  11 //  DESCRIPTION:   The platform supports __int128.
  12
  13 #include <cstdlib>
  14 #include <stdio.h>
  15 #include <limits.h>
  16
  17 namespace boost_has_int128{
  18
  19 #ifdef __GNUC__
  20 __extension__ typedef __int128 my_int128_t;
  21 __extension__ typedef unsigned __int128 my_uint128_t;
  22 #else
  23 typedef __int128 my_int128_t;
  24 typedef unsigned __int128 my_uint128_t;
  25 #endif
  26
  27 my_uint128_t volatile g_ui128 = 0;
  28 unsigned long volatile g_ul = 0;
  29
  30 int test()
  31 {
  32    my_int128_t si128 = 0;
  33    (void)&si128;
  34
  35    // Some compilers have seriously broken __int128 implementations, so we need to do a little more than simply check if we can declare variables with __int128...
  36    // #1: check __int128 size
  37    if (sizeof(my_uint128_t) < (128 / CHAR_BIT))
  38    {
  39       fputs("Type too small.", stderr);
  40       return 1;
  41    }
  42
  43    // #2: check result of computation with __int128
  44    my_uint128_t p1 = 1;
  45    my_uint128_t p2 = 1;
  46    unsigned int i = 0;
  47    for (; i < 180; i++)
  48    {
  49       g_ui128 = p1 + p2;
  50       if (g_ui128 < p1)
  51       {
  52          fputs("Unexpected overflow.", stderr);
  53          return 1;
  54       }
  55       p2 = p1;
  56       p1 = g_ui128;
  57    }
  58
  59    g_ul = static_cast<unsigned long>((g_ui128 >> 92) & 0xFFFFFFFFUL);
  60    g_ul -= 1216382273UL;
  61    if (g_ul != 0)
  62    {
  63       fputs("Incorrect computation result.", stderr);
  64       return 1;
  65    }
  66
  67    return 0;
  68 }
  69
  70 }
  71
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