How to check aes-ni are supported by CPU?

Question

I searching for solution, how to check aes-ni are available on CPU. I need to put this information in my application, so i'm not looking for any CPU-Z, bash commands or something. I know that it is seen as aes flag. I have no idea how to check it in assembly or c. Main application is written in C#, but it doesn't matter.

Answer 1

This information is returned by the cpuid instruction. Pass in eax=1 and bit #25 in ecx will show support. See the intel instruction set reference for more details. Sample code:

mov eax, 1
cpuid
test ecx, 1<<25
jz no_aesni

Also, you might just try executing it and catch the exception.

Answer 2

In visual C++

static bool GetNNICapability()
{
    unsigned int b;

    __asm
    {
        mov     eax, 1
        cpuid
        mov     b, ecx
    }

    return (b & (1 << 25)) != 0;
}