core/detail/cpu_info.hpp

0001 //
0002 // Copyright (c) 2017 Vinnie Falco (vinnie dot falco at gmail dot com)
0003 //
0004 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0005 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // Official repository: https://github.com/boostorg/beast
0008 //
0009
0010 #ifndef BOOST_BEAST_DETAIL_CPU_INFO_HPP
0011 #define BOOST_BEAST_DETAIL_CPU_INFO_HPP
0012
0013 #include <boost/config.hpp>
0014
0015 #ifndef BOOST_BEAST_NO_INTRINSICS
0016 # if defined(BOOST_MSVC) || ((defined(BOOST_GCC) || defined(BOOST_CLANG)) && defined(__SSE4_2__))
0017 #  define BOOST_BEAST_NO_INTRINSICS 0
0018 # else
0019 #  define BOOST_BEAST_NO_INTRINSICS 1
0020 # endif
0021 #endif
0022
0023 #if ! BOOST_BEAST_NO_INTRINSICS
0024
0025 #ifdef BOOST_MSVC
0026 #include <intrin.h> // __cpuid
0027 #else
0028 #include <cpuid.h>  // __get_cpuid
0029 #endif
0030
0031 namespace boost {
0032 namespace beast {
0033 namespace detail {
0034
0035 /*  Portions from Boost,
0036     Copyright Andrey Semashev 2007 - 2015.
0037 */
0038 template<class = void>
0039 void
0040 cpuid(
0041     std::uint32_t id,
0042     std::uint32_t& eax,
0043     std::uint32_t& ebx,
0044     std::uint32_t& ecx,
0045     std::uint32_t& edx)
0046 {
0047 #ifdef BOOST_MSVC
0048     int regs[4];
0049     __cpuid(regs, id);
0050     eax = regs[0];
0051     ebx = regs[1];
0052     ecx = regs[2];
0053     edx = regs[3];
0054 #else
0055     __get_cpuid(id, &eax, &ebx, &ecx, &edx);
0056 #endif
0057 }
0058
0059 struct cpu_info
0060 {
0061     bool sse42 = false;
0062
0063     cpu_info();
0064 };
0065
0066 inline
0067 cpu_info::
0068 cpu_info()
0069 {
0070     constexpr std::uint32_t SSE42 = 1 << 20;
0071
0072     std::uint32_t eax = 0;
0073     std::uint32_t ebx = 0;
0074     std::uint32_t ecx = 0;
0075     std::uint32_t edx = 0;
0076
0077     cpuid(0, eax, ebx, ecx, edx);
0078     if(eax >= 1)
0079     {
0080         cpuid(1, eax, ebx, ecx, edx);
0081         sse42 = (ecx & SSE42) != 0;
0082     }
0083 }
0084
0085 template<class = void>
0086 cpu_info const&
0087 get_cpu_info()
0088 {
0089     static cpu_info const ci;
0090     return ci;
0091 }
0092
0093 } // detail
0094 } // beast
0095 } // boost
0096
0097 #endif
0098
0099 #endif