/*
Test for 4th generation Intel Core processor family features (e.g. Haswell)
From https://software.intel.com/en-us/articles/how-to-detect-new-instruction-support-in-the-4th-generation-intel-core-processor-family
*/

#include <stdint.h>
#if defined(_MSC_VER)
# include <intrin.h>
#endif

static void run_cpuid(uint32_t eax, uint32_t ecx, uint32_t* abcd)
{
#if defined(_MSC_VER)
    __cpuidex(abcd, eax, ecx);
#else
    uint32_t ebx = 0, edx;
# if defined( __i386__ ) && defined ( __PIC__ )
     /* in case of PIC under 32-bit EBX cannot be clobbered */
    __asm__ ( "movl %%ebx, %%edi \n\t cpuid \n\t xchgl %%ebx, %%edi" : "=D" (ebx),
# else
    __asm__ ( "cpuid" : "+b" (ebx),
# endif
              "+a" (eax), "+c" (ecx), "=d" (edx) );
    abcd[0] = eax; abcd[1] = ebx; abcd[2] = ecx; abcd[3] = edx;
#endif
}

static int check_xcr0_ymm()
{
    uint32_t xcr0;
#if defined(_MSC_VER)
    xcr0 = (uint32_t)_xgetbv(0);  /* min VS2010 SP1 compiler is required */
#else
    __asm__ ("xgetbv" : "=a" (xcr0) : "c" (0) : "%edx" );
#endif
    return ((xcr0 & 6) == 6); /* checking if xmm and ymm state are enabled in XCR0 */
}

int check_4th_gen_intel_core_features()
{
    uint32_t abcd[4];
    uint32_t fma_movbe_osxsave_mask = ((1 << 12) | (1 << 22) | (1 << 27));
    uint32_t avx2_bmi12_mask = (1 << 5) | (1 << 3) | (1 << 8);

    extern int errno;

    /* CPUID.(EAX=01H, ECX=0H):ECX.FMA[bit 12]==1   &&
       CPUID.(EAX=01H, ECX=0H):ECX.MOVBE[bit 22]==1 &&
       CPUID.(EAX=01H, ECX=0H):ECX.OSXSAVE[bit 27]==1 */
    run_cpuid( 1, 0, abcd );

    if (errno)
        return 0;

    if ( (abcd[2] & fma_movbe_osxsave_mask) != fma_movbe_osxsave_mask )
        return 0;

    if ( ! check_xcr0_ymm() )
        return 0;

    /*  CPUID.(EAX=07H, ECX=0H):EBX.AVX2[bit 5]==1  &&
        CPUID.(EAX=07H, ECX=0H):EBX.BMI1[bit 3]==1  &&
        CPUID.(EAX=07H, ECX=0H):EBX.BMI2[bit 8]==1  */
    run_cpuid( 7, 0, abcd );
    if ( (abcd[1] & avx2_bmi12_mask) != avx2_bmi12_mask )
        return 0;

    /* CPUID.(EAX=80000001H):ECX.LZCNT[bit 5]==1 */
    run_cpuid( 0x80000001, 0, abcd );
    if ( (abcd[2] & (1 << 5)) == 0)
        return 0;

    return 1;
}