inline bool XMVerifyCPUSupport()

in Inc/DirectXMathMisc.inl [1972:2042]

• 61 lines of code
• 21 McCabe index (conditional complexity)

inline bool XMVerifyCPUSupport() noexcept
{
#if defined(_XM_SSE_INTRINSICS_) && !defined(_XM_NO_INTRINSICS_)
    int CPUInfo[4] = { -1 };
#if defined(__clang__) || defined(__GNUC__)
    __cpuid(0, CPUInfo[0], CPUInfo[1], CPUInfo[2], CPUInfo[3]);
#else
    __cpuid(CPUInfo, 0);
#endif

#ifdef __AVX2__
    if (CPUInfo[0] < 7)
        return false;
#else
    if (CPUInfo[0] < 1)
        return false;
#endif

#if defined(__clang__) || defined(__GNUC__)
    __cpuid(1, CPUInfo[0], CPUInfo[1], CPUInfo[2], CPUInfo[3]);
#else
    __cpuid(CPUInfo, 1);
#endif

#if defined(__AVX2__) || defined(_XM_AVX2_INTRINSICS_)
    // The compiler can emit FMA3 instructions even without explicit intrinsics use
    if ((CPUInfo[2] & 0x38081001) != 0x38081001)
        return false; // No F16C/AVX/OSXSAVE/SSE4.1/FMA3/SSE3 support
#elif defined(_XM_FMA3_INTRINSICS_) && defined(_XM_F16C_INTRINSICS_)
    if ((CPUInfo[2] & 0x38081001) != 0x38081001)
        return false; // No F16C/AVX/OSXSAVE/SSE4.1/FMA3/SSE3 support
#elif defined(_XM_FMA3_INTRINSICS_)
    if ((CPUInfo[2] & 0x18081001) != 0x18081001)
        return false; // No AVX/OSXSAVE/SSE4.1/FMA3/SSE3 support
#elif defined(_XM_F16C_INTRINSICS_)
    if ((CPUInfo[2] & 0x38080001) != 0x38080001)
        return false; // No F16C/AVX/OSXSAVE/SSE4.1/SSE3 support
#elif defined(__AVX__) || defined(_XM_AVX_INTRINSICS_)
    if ((CPUInfo[2] & 0x18080001) != 0x18080001)
        return false; // No AVX/OSXSAVE/SSE4.1/SSE3 support
#elif defined(_XM_SSE4_INTRINSICS_)
    if ((CPUInfo[2] & 0x80001) != 0x80001)
        return false; // No SSE3/SSE4.1 support
#elif defined(_XM_SSE3_INTRINSICS_)
    if (!(CPUInfo[2] & 0x1))
        return false; // No SSE3 support
#endif

    // The x64 processor model requires SSE2 support, but no harm in checking
    if ((CPUInfo[3] & 0x6000000) != 0x6000000)
        return false; // No SSE2/SSE support

#if defined(__AVX2__) || defined(_XM_AVX2_INTRINSICS_)
#if defined(__clang__) || defined(__GNUC__)
    __cpuid_count(7, 0, CPUInfo[0], CPUInfo[1], CPUInfo[2], CPUInfo[3]);
#else
    __cpuidex(CPUInfo, 7, 0);
#endif
    if (!(CPUInfo[1] & 0x20))
        return false; // No AVX2 support
#endif

    return true;
#elif defined(_XM_ARM_NEON_INTRINSICS_) && !defined(_XM_NO_INTRINSICS_)
    // ARM-NEON support is required for the Windows on ARM platform
    return true;
#else
    // No intrinsics path always supported
    return true;
#endif
}