Within my c++ program is there a way to check if the CPU has AES-NI

Question

I want to be able to check if a CPU has AES-NI available to it with C++ code on windows. (MinGW GCC)

I found a solution to this written in C# with visual studio.

Test for AES-NI instructions from C#

 private static bool IsAESNIPresent()
 {
    byte[] sn = new byte[16]; // !!! Here were 8 bytes

    if (!ExecuteCode(ref sn))
        return false;

    var ecx = BitConverter.ToUInt32(sn, 8);
    return (ecx & (1 << 25)) != 0;
 }

Is there an easy way to do the same with c++? (GCC)

Answer 1

There is some code in pycrypto that seems to be applicable. I took the essential parts of the code for testing:

#include <cpuid.h>
#include <stdint.h>
#include <stdio.h>

int main()
{
    uint32_t eax, ebx, ecx, edx;

    eax = ebx = ecx = edx = 0;
    __get_cpuid(1, &eax, &ebx, &ecx, &edx);
    printf("%08x %08x %08x %08x\n", eax, ebx, ecx, edx);
    printf("Has AES-NI: %d\n", (ecx & bit_AES) > 0);

    return 0;
}

The results seem to correspond with the information provided by /proc/cpuinfo or information provided by intel web pages.

For other capabilities, see clang documentation

Answer 2

For giggles you can do this...

int have_aes_ni = (((int(*)())"1\xc0\xb0\1\xf\xa2\x89\xc8\xc3")()>>25)&1;

...but you'll have to pass /SECTION:.data,RWE to the linker and you will be frowned upon by your professional colleagues. You can brag about how your code also works in Linux as Security escorts you out of the facility.

On Windows since Visual C++ 2005 you can do something like

#include<intrin.h>

...

  int regs[4];
  __cpuid( regs, 1 );
  int have_aes_ni = ( regs[2] >> 25 ) & 1;

EDIT: I didn't catch that you were using mingw, where intrin.h may not be available. In that case, J J. Hakala's answer is probably better.