How to check AES-NI support with __cpuid?

Question

I'm looking for a way to check whether or not does my CPU support AES-NI instructions. I found on the Internet a lot of things, that worked but a lot of them were inline assembly code and since I'm under Microsoft Visual Studio and that I'm compiling in x64, that doesn't work. Visual Studio doesn't support x64 inline assembly code and x64 is crucial to me.

So I found the intrinsic function __cpuid(). The thing is that I don't know a word of assembly / intrinsic uses etc... ( I was just copy-pasting the code I found )

So I'm here to ask you about the code below I wrote on my own using pieces of code of the Internet. The output is "AES-Ni supported" but it doesn't mean that my code is right and really retrieving the AES-NI capacity of my CPU.

int cpuInfo[4] = { -1 };

__cpuid(cpuInfo, 1);
_Bool returned = ((cpuInfo[3] & 0x2000000) != 0);

if (returned == 1)
    printf("AES-NI supported");
else
    printf("AES-NI not-supported");

Answer 1

The AES bit is in ECX (25th bit), so you should use cpuInfo[2].