Determine processor support for SSE2?

Question

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)
         


        

Answer 1

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.

Answer 2

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

Answer 3

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;

Answer 4

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.