Identify if CPU is x86_64v3 capable

Readme.md

Detect x86_64v3 CPU support

This C++ program printout ends with "x86_64v3 supported" if x86_64v3 is supported. Some Linux distributions such as RHEL 10 require x86_64v3 support.

Works across operating systems and even with Rosetta 2 on Apple Silicon Macs.

Computers with an x86 CPU can build and run this program natively.

cmake -B build
cmake --build build

build/x86cap

Apple Silicon Macs can build and run this program using AppleClang and Rosetta 2.

arch -x86_64 cmake -B build

cmake --build build

build/x86cap

With current Rosetta 2 and M1 Apple Silicon CPU, "v2" is the highest level supported.

Benchmarks

Phoronix has written several articles on benchmarking operating systems with "v3" enabled:

• Ubuntu v3 benchmarks
• CentOS 10 benchmarks

References

• Microsoft code for Windows that we enhanced to check more flags
• CPU level
• CPU feature bit IDs

CMakeLists.txt

cmake_minimum_required(VERSION 3.19...3.31)

project(InstructionSet LANGUAGES CXX)

set(CMAKE_CXX_SCAN_FOR_MODULES OFF)

include(CheckIncludeFileCXX)

set(CMAKE_CXX_STANDARD 11)

message(STATUS "CMAKE_SYSTEM_PROCESSOR: ${CMAKE_SYSTEM_PROCESSOR}")

if(CMAKE_SYSTEM_PROCESSOR MATCHES "^(x86|AMD64)")
  if(WIN32)
    add_executable(InstructionSet windows.cpp)
  else()
    check_include_file_cxx("cpuid.h" HAVE_CPUID)

    if(HAVE_CPUID)
     add_executable(InstructionSet unix.cpp)
    endif()
  endif()
endif()

option(steinwurf "Use Steinwurf's cpuid library" ON)
if(NOT steinwurf)
  return()
endif()


include(FetchContent)

FetchContent_Populate(cpuid_steinwurf
URL https://github.com/steinwurf/cpuid/archive/refs/tags/9.0.1.tar.gz
)

FetchContent_Populate(platform_steinwurf
URL https://github.com/steinwurf/platform/archive/refs/tags/5.1.1.tar.gz
)

set(s ${cpuid_steinwurf_SOURCE_DIR}/src/cpuid)

add_library(cpuid OBJECT ${s}/cpuinfo.cpp ${s}/version.cpp)
target_include_directories(cpuid PUBLIC ${s} ${platform_steinwurf_SOURCE_DIR}/src)

add_executable(x86cap steinwurf.cpp)
target_link_libraries(x86cap PRIVATE cpuid)

file(GENERATE OUTPUT .gitignore CONTENT "*")

steinwurf.cpp

#include <iostream>
#include <cstdlib>

#include <cpuinfo.hpp>

int main()
{
  cpuid::cpuinfo m;

// v2: has all of: cx16 lahf_lm popcnt sse4_1 sse4_2 ssse3
// note: cx16 == cmpxchg16b, lahf_lm == lahf
  if(m.has_sse4_1() && m.has_sse4_2() && m.has_ssse3())
    std::cout << "x86_64v2 supported\n";
// v3: has all of: avx avx2 bmi1 bmi2 f16c fma abm movbe xsave
// note: for Intel, lzcnt is designated for abm

  if(m.has_avx() && m.has_avx2() && m.has_f16c())
    std::cout << "x86_64v3 supported\n";

// v4: has all of: avx512f avx512bw avx512cd avx512dq avx512vl
  if(m.has_avx512_f() && m.has_avx512_bw() && m.has_avx512_cd() && m.has_avx512_dq() && m.has_avx512_vl())
    std::cout << "x86_64v4 supported\n";

  return EXIT_SUCCESS;
}

unix.cpp

// using C++ on Linux, determine the x86_64 instruction set level e.g. v2, v3, or v4

#include <iostream>
#include <cstdint>
#include <cstdlib>
#include <string>
#include <vector>
#include <bitset>

#include <cpuid.h>

int main(){

  unsigned int eax=0, ebx=0, ecx=0, edx=0;

  if (__get_cpuid(0, &eax, &ebx, &ecx, &edx) == 0) {
    std::cerr << "CPUID not supported\n";
    return EXIT_FAILURE;
  }

  unsigned int nIds = eax;

  std::string vendor(reinterpret_cast<const char*>(&ebx), 4);
  vendor += std::string(reinterpret_cast<const char*>(&edx), 4);
  vendor += std::string(reinterpret_cast<const char*>(&ecx), 4);
  std::cout << "Vendor: " << vendor << "\n";

  if (nIds < 1) {
    std::cerr << "CPUID leaf 1 not supported\n";
    return EXIT_FAILURE;
  }

  ebx = 0;
  ecx = 0;
  edx = 0;

  if(__get_cpuid(1, &eax, &ebx, &ecx, &edx) == 0){
    std::cerr << "CPUID 1 not supported\n";
    return EXIT_FAILURE;
  }

  std::bitset<32> const bECX(ecx);

  bool const cx16   = bECX[13];
  if(cx16) std::cout << "CX16 ";

  bool const lahf_lm = bECX[20];
  if (lahf_lm) std::cout << "LAHF_LM ";

  bool const popcnt = bECX[23];
  if (popcnt) std::cout << "POPCNT ";

  bool const sse4_1 = bECX[19];
  if (sse4_1) std::cout << "SSE4.1 ";

  bool const sse4_2 = bECX[20];
  if (sse4_2) std::cout << "SSE4.2 ";

  bool const ssse3 = bECX[9];
  if (ssse3) std::cout << "SSSE3 ";

  bool const avx   = bECX[28];
  if (avx) std::cout << "AVX ";

  bool const avx2  = bECX[5];
  if (avx2) std::cout << "AVX2 ";

  bool const f16c  = bECX[29];
  if (f16c) std::cout << "F16C ";

  bool const fma   = bECX[12];
  if (fma) std::cout << "FMA ";

  bool const abm = bECX[5] && vendor == "AuthenticAMD";
  if (abm) std::cout << "ABM ";

  bool const lzcnt = bECX[5] && vendor == "GenuineIntel";
  if (lzcnt) std::cout << "LZCNT ";

  bool const movbe = bECX[22];
  if (movbe) std::cout << "MOVBE ";

  bool const xsave = bECX[26];
  if (xsave) std::cout << "XSAVE ";

  std::cout << "\n";

  if (cx16 && lahf_lm && popcnt && sse4_1 && sse4_2 && ssse3)
    std::cout << "x86_64v2 supported\n";

  bool v4 = false;

  if(nIds >= 7){

  ebx = 0;
  ecx = 0;
  edx = 0;

  if(__get_cpuid_count(7, 0, &eax, &ebx, &ecx, &edx) == 0){
    std::cerr << "CPUID leaf 7, subleaf 0 not supported\n";
    return EXIT_FAILURE;
  }

  std::bitset<32> const b(ebx);

  bool const bmi1 = b[3];
  if (bmi1) std::cout << "BMI1 ";

  bool const bmi2 = b[8];
  if (bmi2) std::cout << "BMI2 ";

  bool const avx512f = b[16];
  if (avx512f) std::cout << "AVX512F ";

  bool const avx512bw = b[30];
  if (avx512bw) std::cout << "AVX512BW ";

  bool const avx512cd = b[28];
  if (avx512cd) std::cout << "AVX512CD ";

  bool const avx512dq = b[17];
  if (avx512dq) std::cout << "AVX512DQ ";

  bool const avx512vl = b[31];
  if (avx512vl) std::cout << "AVX512VL ";

  // v3: has all of: avx avx2 lzcnt bmi1 bmi2 f16c fma movbe xsave
  // abm = lzcnt & bmi1 & bmi2
  if(avx && avx2 && bmi1 && bmi2 && f16c && fma && (abm || lzcnt) && movbe && xsave)
    std::cout << "\nx86_64v3 supported\n";

  // v4: has all of: avx512f avx512bw avx512cd avx512dq avx512vl
  if (avx512f && avx512bw && avx512cd && avx512dq && avx512vl)
    std::cout << "x86_64v4 supported\n";
  }

  return EXIT_SUCCESS;
}

windows.cpp

// Determine supported x86 CPU instruction set extensions
//
// For x86, x86_64 CPUs on WINDOWS ONLY

#include <iostream>
#include <vector>
#include <bitset>
#include <array>
#include <string>
#include <cstring>

#include <intrin.h>

class InstructionSet
{
    // forward declarations
    class InstructionSet_Internal;

public:
    // getters
    static std::string Vendor(void) { return CPU_Rep.vendor_; }
    static std::string Brand(void) { return CPU_Rep.brand_; }

    static bool SSE3(void) { return CPU_Rep.f_1_ECX_[0]; }
    static bool PCLMULQDQ(void) { return CPU_Rep.f_1_ECX_[1]; }
    static bool MONITOR(void) { return CPU_Rep.f_1_ECX_[3]; }
    static bool SSSE3(void) { return CPU_Rep.f_1_ECX_[9]; }
    static bool FMA(void) { return CPU_Rep.f_1_ECX_[12]; }
    static bool CMPXCHG16B(void) { return CPU_Rep.f_1_ECX_[13]; }
    static bool SSE41(void) { return CPU_Rep.f_1_ECX_[19]; }
    static bool SSE42(void) { return CPU_Rep.f_1_ECX_[20]; }
    static bool MOVBE(void) { return CPU_Rep.f_1_ECX_[22]; }
    static bool POPCNT(void) { return CPU_Rep.f_1_ECX_[23]; }
    static bool AES(void) { return CPU_Rep.f_1_ECX_[25]; }
    static bool XSAVE(void) { return CPU_Rep.f_1_ECX_[26]; }
    static bool OSXSAVE(void) { return CPU_Rep.f_1_ECX_[27]; }
    static bool AVX(void) { return CPU_Rep.f_1_ECX_[28]; }
    static bool F16C(void) { return CPU_Rep.f_1_ECX_[29]; }
    static bool RDRAND(void) { return CPU_Rep.f_1_ECX_[30]; }

    static bool MSR(void) { return CPU_Rep.f_1_EDX_[5]; }
    static bool CX8(void) { return CPU_Rep.f_1_EDX_[8]; }
    static bool SEP(void) { return CPU_Rep.f_1_EDX_[11]; }
    static bool CMOV(void) { return CPU_Rep.f_1_EDX_[15]; }
    static bool CLFSH(void) { return CPU_Rep.f_1_EDX_[19]; }
    static bool MMX(void) { return CPU_Rep.f_1_EDX_[23]; }
    static bool FXSR(void) { return CPU_Rep.f_1_EDX_[24]; }
    static bool SSE(void) { return CPU_Rep.f_1_EDX_[25]; }
    static bool SSE2(void) { return CPU_Rep.f_1_EDX_[26]; }

    static bool FSGSBASE(void) { return CPU_Rep.f_7_EBX_[0]; }
    static bool BMI1(void) { return CPU_Rep.f_7_EBX_[3]; }
    static bool HLE(void) { return CPU_Rep.isIntel_ && CPU_Rep.f_7_EBX_[4]; }
    static bool AVX2(void) { return CPU_Rep.f_7_EBX_[5]; }
    static bool BMI2(void) { return CPU_Rep.f_7_EBX_[8]; }
    static bool ERMS(void) { return CPU_Rep.f_7_EBX_[9]; }
    static bool INVPCID(void) { return CPU_Rep.f_7_EBX_[10]; }
    static bool RTM(void) { return CPU_Rep.isIntel_ && CPU_Rep.f_7_EBX_[11]; }
    static bool AVX512F(void) { return CPU_Rep.f_7_EBX_[16]; }
    static bool RDSEED(void) { return CPU_Rep.f_7_EBX_[18]; }
    static bool ADX(void) { return CPU_Rep.f_7_EBX_[19]; }
    static bool AVX512VL(void) { return CPU_Rep.f_7_EBX_[31]; }
    static bool AVX512PF(void) { return CPU_Rep.f_7_EBX_[26]; }
    static bool AVX512ER(void) { return CPU_Rep.f_7_EBX_[27]; }
    static bool AVX512DQ(void) { return CPU_Rep.f_7_EBX_[17]; }
    static bool AVX512CD(void) { return CPU_Rep.f_7_EBX_[28]; }
    static bool AVX512BW(void) { return CPU_Rep.f_7_EBX_[30]; }
    static bool SHA(void) { return CPU_Rep.f_7_EBX_[29]; }

    static bool PREFETCHWT1(void) { return CPU_Rep.f_7_ECX_[0]; }

    static bool LAHF(void) { return CPU_Rep.f_81_ECX_[0]; }
    static bool LZCNT(void) { return CPU_Rep.isIntel_ && CPU_Rep.f_81_ECX_[5]; }
    static bool ABM(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_ECX_[5]; }
    static bool SSE4a(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_ECX_[6]; }
    static bool XOP(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_ECX_[11]; }
    static bool TBM(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_ECX_[21]; }

    static bool SYSCALL(void) { return CPU_Rep.isIntel_ && CPU_Rep.f_81_EDX_[11]; }
    static bool MMXEXT(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_EDX_[22]; }
    static bool RDTSCP(void) { return CPU_Rep.isIntel_ && CPU_Rep.f_81_EDX_[27]; }
    static bool _3DNOWEXT(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_EDX_[30]; }
    static bool _3DNOW(void) { return CPU_Rep.isAMD_ && CPU_Rep.f_81_EDX_[31]; }

    static bool isIntel(void) { return CPU_Rep.isIntel_; }
    static bool isAMD(void) { return CPU_Rep.isAMD_; }

private:
    static const InstructionSet_Internal CPU_Rep;

    class InstructionSet_Internal
    {
    public:
        InstructionSet_Internal()
            : nIds_{ 0 },
            nExIds_{ 0 },
            isIntel_{ false },
            isAMD_{ false },
            f_1_ECX_{ 0 },
            f_1_EDX_{ 0 },
            f_7_EBX_{ 0 },
            f_7_ECX_{ 0 },
            f_81_ECX_{ 0 },
            f_81_EDX_{ 0 },
            data_{},
            extdata_{}
        {
            //int cpuInfo[4] = {-1};


            // Calling __cpuid with 0x0 as the function_id argument
            // gets the number of the highest valid function ID.
            std::array<int, 4> cpui;
            __cpuid(cpui.data(), 0);

            nIds_ = cpui[0];

            for (int i = 0; i <= nIds_; ++i)
            {
                __cpuidex(cpui.data(), i, 0);
                data_.push_back(cpui);
            }

            // Capture vendor string
            char vendor[0x20];
            memset(vendor, 0, sizeof(vendor));
            *reinterpret_cast<int*>(vendor) = data_[0][1];
            *reinterpret_cast<int*>(vendor + 4) = data_[0][3];
            *reinterpret_cast<int*>(vendor + 8) = data_[0][2];
            vendor_ = vendor;
            if (vendor_ == "GenuineIntel")
            {
                isIntel_ = true;
            }
            else if (vendor_ == "AuthenticAMD")
            {
                isAMD_ = true;
            }

            // load bitset with flags for function 0x00000001
            if (nIds_ >= 1)
            {
                f_1_ECX_ = data_[1][2];
                f_1_EDX_ = data_[1][3];
            }

            // load bitset with flags for function 0x00000007
            if (nIds_ >= 7)
            {
                f_7_EBX_ = data_[7][1];
                f_7_ECX_ = data_[7][2];
            }

            // Calling __cpuid with 0x80000000 as the function_id argument
            // gets the number of the highest valid extended ID.
            __cpuid(cpui.data(), 0x80000000);
            nExIds_ = cpui[0];

            char brand[0x40];
            memset(brand, 0, sizeof(brand));

            for (int i = 0x80000000; i <= nExIds_; ++i)
            {
                __cpuidex(cpui.data(), i, 0);
                extdata_.push_back(cpui);
            }

            // load bitset with flags for function 0x80000001
            if (nExIds_ >= 0x80000001)
            {
                f_81_ECX_ = extdata_[1][2];
                f_81_EDX_ = extdata_[1][3];
            }

            // Interpret CPU brand string if reported
            if (nExIds_ >= 0x80000004)
            {
                memcpy(brand, extdata_[2].data(), sizeof(cpui));
                memcpy(brand + 16, extdata_[3].data(), sizeof(cpui));
                memcpy(brand + 32, extdata_[4].data(), sizeof(cpui));
                brand_ = brand;
            }
        };

        int nIds_;
        int nExIds_;
        std::string vendor_;
        std::string brand_;
        bool isIntel_;
        bool isAMD_;
        std::bitset<32> f_1_ECX_;
        std::bitset<32> f_1_EDX_;
        std::bitset<32> f_7_EBX_;
        std::bitset<32> f_7_ECX_;
        std::bitset<32> f_81_ECX_;
        std::bitset<32> f_81_EDX_;

        std::vector<std::array<int, 4>> data_;
        std::vector<std::array<int, 4>> extdata_;
    };
};

// Initialize static member data
const InstructionSet::InstructionSet_Internal InstructionSet::CPU_Rep;

// Print out supported instruction set extensions
int main()
{
    auto& outstream = std::cout;

    auto support_message = [&outstream](std::string isa_feature, bool is_supported) {
        outstream << isa_feature << (is_supported ? " supported" : " not supported") << std::endl;
    };

    std::cout << InstructionSet::Vendor() << std::endl;
    std::cout << InstructionSet::Brand() << std::endl;

    support_message("3DNOW",       InstructionSet::_3DNOW());
    support_message("3DNOWEXT",    InstructionSet::_3DNOWEXT());
    support_message("ABM",         InstructionSet::ABM());
    support_message("ADX",         InstructionSet::ADX());
    support_message("AES",         InstructionSet::AES());
    support_message("AVX",         InstructionSet::AVX());
    support_message("AVX2",        InstructionSet::AVX2());
    support_message("AVX512CD",    InstructionSet::AVX512CD());
    support_message("AVX512ER",    InstructionSet::AVX512ER());
    support_message("AVX512F",     InstructionSet::AVX512F());
    support_message("AVX512PF",    InstructionSet::AVX512PF());
    support_message("BMI1",        InstructionSet::BMI1());
    support_message("BMI2",        InstructionSet::BMI2());
    support_message("CLFSH",       InstructionSet::CLFSH());
    support_message("CMPXCHG16B",  InstructionSet::CMPXCHG16B());
    support_message("CX8",         InstructionSet::CX8());
    support_message("ERMS",        InstructionSet::ERMS());
    support_message("F16C",        InstructionSet::F16C());
    support_message("FMA",         InstructionSet::FMA());
    support_message("FSGSBASE",    InstructionSet::FSGSBASE());
    support_message("FXSR",        InstructionSet::FXSR());
    support_message("HLE",         InstructionSet::HLE());
    support_message("INVPCID",     InstructionSet::INVPCID());
    support_message("LAHF",        InstructionSet::LAHF());
    support_message("LZCNT",       InstructionSet::LZCNT());
    support_message("MMX",         InstructionSet::MMX());
    support_message("MMXEXT",      InstructionSet::MMXEXT());
    support_message("MONITOR",     InstructionSet::MONITOR());
    support_message("MOVBE",       InstructionSet::MOVBE());
    support_message("MSR",         InstructionSet::MSR());
    support_message("OSXSAVE",     InstructionSet::OSXSAVE());
    support_message("PCLMULQDQ",   InstructionSet::PCLMULQDQ());
    support_message("POPCNT",      InstructionSet::POPCNT());
    support_message("PREFETCHWT1", InstructionSet::PREFETCHWT1());
    support_message("RDRAND",      InstructionSet::RDRAND());
    support_message("RDSEED",      InstructionSet::RDSEED());
    support_message("RDTSCP",      InstructionSet::RDTSCP());
    support_message("RTM",         InstructionSet::RTM());
    support_message("SEP",         InstructionSet::SEP());
    support_message("SHA",         InstructionSet::SHA());
    support_message("SSE",         InstructionSet::SSE());
    support_message("SSE2",        InstructionSet::SSE2());
    support_message("SSE3",        InstructionSet::SSE3());
    support_message("SSE4.1",      InstructionSet::SSE41());
    support_message("SSE4.2",      InstructionSet::SSE42());
    support_message("SSE4a",       InstructionSet::SSE4a());
    support_message("SSSE3",       InstructionSet::SSSE3());
    support_message("SYSCALL",     InstructionSet::SYSCALL());
    support_message("TBM",         InstructionSet::TBM());
    support_message("XOP",         InstructionSet::XOP());
    support_message("XSAVE",       InstructionSet::XSAVE());

  std::cout << "\n";

  // v2: has all of: cx16 lahf_lm popcnt sse4_1 sse4_2 ssse3
  // note: cx16 == cmpxchg16b, lahf_lm == lahf
  if(InstructionSet::CMPXCHG16B() && InstructionSet::LAHF() && InstructionSet::POPCNT() &&
     InstructionSet::SSE41() && InstructionSet::SSE42() && InstructionSet::SSSE3())
    std::cout << "x86_64v2 supported\n";

  // v3: has all of: avx avx2 bmi1 bmi2 f16c fma abm movbe xsave
  // note: for Intel, lzcnt is designated for abm
  if(InstructionSet::AVX() && InstructionSet::AVX2() && InstructionSet::BMI1() &&
     InstructionSet::BMI2() && InstructionSet::F16C() && InstructionSet::FMA() &&
     InstructionSet::MOVBE() && InstructionSet::XSAVE() &&
     ((InstructionSet::isAMD() && InstructionSet::ABM()) || (InstructionSet::isIntel() && InstructionSet::LZCNT())))
    std::cout << "x86_64v3 supported\n";

  // v4: has all of: avx512f avx512bw avx512cd avx512dq avx512vl
    if(InstructionSet::AVX512F() && InstructionSet::AVX512CD() && InstructionSet::AVX512BW() &&
         InstructionSet::AVX512DQ() && InstructionSet::AVX512VL())
        std::cout << "x86_64v4 supported\n";

  return 0;
}