| 1 | // endian/detail/intrinsic.hpp -------------------------------------------------------// |
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| 2 | |
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| 3 | // Copyright (C) 2012 David Stone |
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| 4 | // Copyright Beman Dawes 2013 |
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| 5 | |
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| 6 | // Distributed under the Boost Software License, Version 1.0. |
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| 7 | // http://www.boost.org/LICENSE_1_0.txt |
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| 8 | |
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| 9 | #ifndef BOOST_ENDIAN_INTRINSIC_HPP |
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| 10 | #define BOOST_ENDIAN_INTRINSIC_HPP |
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| 11 | |
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| 12 | // Allow user to force BOOST_ENDIAN_NO_INTRINSICS in case they aren't available for a |
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| 13 | // particular platform/compiler combination. Please report such platform/compiler |
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| 14 | // combinations to the Boost mailing list. |
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| 15 | #ifndef BOOST_ENDIAN_NO_INTRINSICS |
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| 16 | |
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| 17 | #ifndef __has_builtin // Optional of course |
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| 18 | #define __has_builtin(x) 0 // Compatibility with non-clang compilers |
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| 19 | #endif |
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| 20 | |
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| 21 | #if defined(_MSC_VER) && ( !defined(__clang__) || defined(__c2__) ) |
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| 22 | // Microsoft documents these as being compatible since Windows 95 and specifically |
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| 23 | // lists runtime library support since Visual Studio 2003 (aka 7.1). |
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| 24 | // Clang/c2 uses the Microsoft rather than GCC intrinsics, so we check for |
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| 25 | // defined(_MSC_VER) before defined(__clang__) |
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| 26 | # define BOOST_ENDIAN_INTRINSIC_MSG "cstdlib _byteswap_ushort, etc." |
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| 27 | # include <cstdlib> |
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| 28 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) _byteswap_ushort(x) |
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| 29 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_4(x) _byteswap_ulong(x) |
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| 30 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_8(x) _byteswap_uint64(x) |
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| 31 | |
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| 32 | // GCC and Clang recent versions provide intrinsic byte swaps via builtins |
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| 33 | #elif (defined(__clang__) && __has_builtin(__builtin_bswap32) && __has_builtin(__builtin_bswap64)) \ |
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| 34 | || (defined(__GNUC__ ) && \ |
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| 35 | (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))) |
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| 36 | # define BOOST_ENDIAN_INTRINSIC_MSG "__builtin_bswap16, etc." |
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| 37 | // prior to 4.8, gcc did not provide __builtin_bswap16 on some platforms so we emulate it |
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| 38 | // see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52624 |
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| 39 | // Clang has a similar problem, but their feature test macros make it easier to detect |
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| 40 | # if (defined(__clang__) && __has_builtin(__builtin_bswap16)) \ |
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| 41 | || (defined(__GNUC__) &&(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8))) |
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| 42 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) __builtin_bswap16(x) |
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| 43 | # else |
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| 44 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) __builtin_bswap32((x) << 16) |
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| 45 | # endif |
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| 46 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_4(x) __builtin_bswap32(x) |
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| 47 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_8(x) __builtin_bswap64(x) |
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| 48 | |
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| 49 | # define BOOST_ENDIAN_CONSTEXPR_INTRINSICS |
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| 50 | |
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| 51 | // Linux systems provide the byteswap.h header, with |
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| 52 | #elif defined(__linux__) |
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| 53 | // don't check for obsolete forms defined(linux) and defined(__linux) on the theory that |
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| 54 | // compilers that predefine only these are so old that byteswap.h probably isn't present. |
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| 55 | # define BOOST_ENDIAN_INTRINSIC_MSG "byteswap.h bswap_16, etc." |
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| 56 | # include <byteswap.h> |
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| 57 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_2(x) bswap_16(x) |
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| 58 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_4(x) bswap_32(x) |
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| 59 | # define BOOST_ENDIAN_INTRINSIC_BYTE_SWAP_8(x) bswap_64(x) |
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| 60 | |
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| 61 | #else |
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| 62 | # define BOOST_ENDIAN_NO_INTRINSICS |
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| 63 | # define BOOST_ENDIAN_INTRINSIC_MSG "no byte swap intrinsics" |
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| 64 | #endif |
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| 65 | |
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| 66 | #elif !defined(BOOST_ENDIAN_INTRINSIC_MSG) |
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| 67 | # define BOOST_ENDIAN_INTRINSIC_MSG "no byte swap intrinsics" |
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| 68 | #endif // BOOST_ENDIAN_NO_INTRINSICS |
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| 69 | #endif // BOOST_ENDIAN_INTRINSIC_HPP |
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| 70 | |
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