cpuid_features.c

#if defined(__GNUC__)
    #include <stdint.h>
    #include <cpuid.h>
#elif defined(_WIN32)
    #include <intrin.h>
    typedef unsigned __int32 uint32_t;
#endif
#include <stdio.h>

/**
 * Calls cpuid with op and store results of eax,ebx,ecx,edx
 * \param op cpuid function (eax input)
 * \param eax content of eax after the call to cpuid
 * \param ebx content of ebx after the call to cpuid
 * \param ecx content of ecx after the call to cpuid
 * \param edx content of edx after the call to cpuid
 */
void cpuid( uint32_t op, uint32_t* eax, uint32_t* ebx, uint32_t* ecx, uint32_t* edx )
{
#if defined(__GNUC__)
  uint32_t r_eax;
  uint32_t r_ebx;
  uint32_t r_ecx;
  uint32_t r_edx;
  // GCC won't allow us to clobber EBX since its used to store the GOT. So we need to
  // lie to GCC and backup/restore EBX without declaring it as clobbered.
  asm volatile( "pushl %%ebx   \n\t"
                "cpuid         \n\t"
                "movl %%ebx, %1\n\t"
                "popl %%ebx    \n\t"
                : "=a"(r_eax), "=r"(r_ebx), "=c"(r_ecx), "=d"(r_edx)
                : "a"(op)
                : "cc" );
  *eax = r_eax;
  *ebx = r_ebx;
  *ecx = r_ecx;
  *edx = r_edx;
#elif defined(_WIN32)
  // MSVC provides a __cpuid function
  int regs[4];
  __cpuid( regs, op );
  *eax = (uint32_t)regs[0];
  *ebx = (uint32_t)regs[1];
  *ecx = (uint32_t)regs[2];
  *edx = (uint32_t)regs[3];
#endif
}

void
print_feature( uint32_t test, const char* name )
{
  printf("%s - %s\n", (test)?"YES":"NO ", name );
}

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

  cpuid( 0, &eax, &ebx, &ecx, &edx );
  uint32_t ids = eax;

  cpuid( 0x80000000, &eax, &ebx, &ecx, &edx );
  uint32_t ex_ids = eax;

  if ( ids >= 1 )
  {
    cpuid( 1, &eax, &ebx, &ecx, &edx );
    print_feature( edx &  (1<< 0), "FPU       (Floating-point Unit on-chip)");
    print_feature( edx &  (1<< 1), "VME       (Virtual Mode Extension)");
    print_feature( edx &  (1<< 2), "DE        (Debugging Extension)");
    print_feature( edx &  (1<< 3), "PSE       (Page Size Extension)");
    print_feature( edx &  (1<< 4), "TSC       (Time Stamp Counter)");
    print_feature( edx &  (1<< 5), "MSR       (Model Specific Registers)");
    print_feature( edx &  (1<< 6), "PAE       (Physical Address Extension)");
    print_feature( edx &  (1<< 7), "MCE       (Machine Check Exception)");
    print_feature( edx &  (1<< 8), "CX8       (CMPXCHG8 Instructions)");
    print_feature( edx &  (1<< 9), "APIC      (On-chip APIC hardware)");
    print_feature( edx &  (1<<11), "SEP       (Fast System Call)");
    print_feature( edx &  (1<<12), "MTRR      (Memory type Range Registers)");
    print_feature( edx &  (1<<13), "PGE       (Page Global Enable)");
    print_feature( edx &  (1<<14), "MCA       (Machine Check Architecture)");
    print_feature( edx &  (1<<15), "CMOV      (Conditional Move Instruction)");
    print_feature( edx &  (1<<16), "PAT       (Page Attribute Table)");
    print_feature( edx &  (1<<17), "PSE36     (36bit Page Size Extension");
    print_feature( edx &  (1<<18), "PSN       (Processor Serial Number)");
    print_feature( edx &  (1<<19), "CLFSH     (CFLUSH Instruction)");
    print_feature( edx &  (1<<21), "DS        (Debug Store)");
    print_feature( edx &  (1<<22), "ACPI      (Thermal Monitor & Software Controlled Clock)");
    print_feature( edx &  (1<<23), "MMX       (Multi-Media Extension)");
    print_feature( edx &  (1<<24), "FXSR      (Fast Floating Point Save & Restore)");
    print_feature( edx &  (1<<25), "SSE       (Streaming SIMD Extension 1)");
    print_feature( edx &  (1<<26), "SSE2      (Streaming SIMD Extension 2)");
    print_feature( edx &  (1<<27), "SS        (Self Snoop)");
    print_feature( edx &  (1<<28), "HTT       (Hyper Threading Technology)");
    print_feature( edx &  (1<<29), "TM        (Thermal Monitor)");
    print_feature( edx &  (1<<31), "PBE       (Pend Break Enabled)");
    print_feature( ecx &  (1<< 0), "SSE3      (Streaming SMD Extension 3)");
    print_feature( ecx &  (1<< 3), "MW        (Monitor Wait Instruction");
    print_feature( ecx &  (1<< 4), "CPL       (CPL-qualified Debug Store)");
    print_feature( ecx &  (1<< 5), "VMX       (Virtual Machine Extensions)");
    print_feature( ecx &  (1<< 7), "EST       (Enchanced Speed Test)");
    print_feature( ecx &  (1<< 8), "TM2       (Thermal Monitor 2)");
    print_feature( ecx &  (1<< 9), "SSSE3     (Supplemental Streaming SIMD Extensions 3)");
    print_feature( ecx &  (1<<10), "L1        (L1 Context ID)");
    print_feature( ecx &  (1<<12), "FMA3      (Fused Multiply-Add 3-operand Form)");
    print_feature( ecx &  (1<<13), "CAE       (Compare And Exchange 16B)");
    print_feature( ecx &  (1<<19), "SSE41     (Streaming SIMD Extensions 4.1)");
    print_feature( ecx &  (1<<20), "SSE42     (Streaming SIMD Extensions 4.2)");
    print_feature( ecx &  (1<<25), "AES       (Advanced Encryption Standard)");
    print_feature( ecx &  (1<<28), "AVX       (Advanced Vector Extensions)");
    print_feature( ecx &  (1<<30), "RDRAND    (Random Number Generator)");
  }
  if ( ids >= 7 )
  {
    cpuid( 7, &eax, &ebx, &ecx, &edx );
    print_feature( ebx &  (1<< 5), "AVX2      (Advanced Vector Extensions 2)");
    print_feature( ebx &  (1<< 3), "BMI1      (Bit Manipulations Instruction Set 1)");
    print_feature( ebx &  (1<< 8), "BMI2      (Bit Manipulations Instruction Set 2)");
    print_feature( ebx &  (1<<19), "ADX       (Multi-Precision Add-Carry Instruction Extensions)");
    print_feature( ebx &  (1<<16), "AVX512F   (512-bit extensions to Advanced Vector Extensions Foundation)");
    print_feature( ebx &  (1<<26), "AVX512PFI (512-bit extensions to Advanced Vector Extensions Prefetch Instructions)");
    print_feature( ebx &  (1<<27), "AVX512ERI (512-bit extensions to Advanced Vector Extensions Exponential and Reciprocal Instructions)");
    print_feature( ebx &  (1<<28), "AVX512CDI (512-bit extensions to Advanced Vector Extensions Conflict Detection Instructions)");
    print_feature( ebx &  (1<<29), "SHA       (Secure Hash Algorithm)");
  }
  if ( ex_ids >= 0x80000001 )
  {
    cpuid( 0x80000001, &eax, &ebx, &ecx, &edx );
    print_feature( edx &  (1<<29), "X64       (64-bit Extensions)");
    print_feature( ecx &  (1<< 5), "LZCNT     (Leading Zero Bit Count Instruction)");
    print_feature( ecx &  (1<< 6), "SSE4A     (Streaming SIMD Extensions 4a)");
    print_feature( ecx &  (1<<16), "FMA4      (Fused Multiply-Add 4-operand Form)"); 
    print_feature( ecx &  (1<<11), "XOP       (Extended Operations)");
  }

  return 0;
}