Determine processor support for SSE2?

问题:

I need to do determine processor support for SSE2 prior installing a software. From what I understand, I came up with this:

bool TestSSE2(char * szErrorMsg)
{
    __try 
    {
        __asm 
        {
              xorpd xmm0, xmm0        // executing SSE2 instruction
        }
    }
        #pragma warning (suppress: 6320)
        __except (EXCEPTION_EXECUTE_HANDLER) 
        {
            if (_exception_code() == STATUS_ILLEGAL_INSTRUCTION) 
            {
                _tcscpy_s(szErrorMsg,MSGSIZE, _T("Streaming SIMD Extensions 2(SSE2) is not supported by the CPU.\r\n Unable to launch APP"));
                return false;

            }
        _tcscpy_s(szErrorMsg,MSGSIZE, _T("Streaming SIMD Extensions 2(SSE2) is not supported by the CPU.\r\n Unable to launch APP"));
        return false;
        }   
    return true;
}

Would this work? I'm not really sure how to test, since my CPU supports it, so I don't get false from the function call.

How do I determine processor support for SSE2?

回答1:

Call CPUID with eax = 1 to load the feature flags in to edx. Bit 26 is set if SSE2 is available. Some code for demonstration purposes, using MSVC++ inline assembly (only for x86 and not portable!):

inline unsigned int get_cpu_feature_flags()
{
    unsigned int features;

    __asm
    {
        // Save registers
        push    eax
        push    ebx
        push    ecx
        push    edx

        // Get the feature flags (eax=1) from edx
        mov     eax, 1
        cpuid
        mov     features, edx

        // Restore registers
        pop     edx
        pop     ecx
        pop     ebx
        pop     eax
    }

    return features;
}

// Bit 26 for SSE2 support
static const bool cpu_supports_sse2 = (cpu_feature_flags & 0x04000000)!=0;

回答2:

I found this one by accident in the MSDN:

BOOL sse2supported = ::IsProcessorFeaturePresent( PF_XMMI64_INSTRUCTIONS_AVAILABLE );

Windows-only, but if you are not interested in anything cross-platform, very simple.

回答3:

The most basic way to check for SSE2 support is by using the CPUID instruction (on platforms where it is available). Either using inline assembly or using compiler intrinsics.

回答4:

You can use the _cpuid function. All is explained in the MSDN.