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detect_mmx.cpp

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/***************************************************************************
 *
 * DetectMMX.cpp
 * by Darryl Agostinelli March 4, 2000
 *
 * Code was adopted from Intel web page
 *
 */

#include "Core/precomp.h"
#include "API/Core/System/system.h"
#include "API/Core/System/cl_assert.h"

static bool do_mmx_test();

bool CL_System::detect_mmx()
{
        static bool has_mmx = false;
        static bool first_time = true;
        
        if (first_time)
        {
                first_time = false;
                has_mmx = do_mmx_test();
        }
        
        return has_mmx;
}

static bool do_mmx_test()
{
#ifdef USE_I386_ASSEMBLER
#ifdef __MSC__
        unsigned long RegEDX;

        try 
        {
                _asm
                {
                        mov eax, 1                      // set up CPUID to return processor version and features
                                                                //      0 = vendor string, 1 = version info, 2 = cache info
                        CPUID                           // code bytes = 0fh,  0a2h
                        mov RegEDX, edx         // features returned in edx
                }
        }
        catch(...)                                      // catch everything
        {
                return false;           // processor does not support CPUID
        }

        if (RegEDX & 0x800000)          // bit 23 is set for MMX technology
        {
                try { _asm {emms} }             // try executing the MMX instruction "emms"
                catch(...) { return false; }
        }
        else
                return false;           // processor supports CPUID but does not support MMX technology

        // if we get here, it means the processor has MMX technology but
        // floating-point emulation is on; so MMX technology is unavailable

        return true;
#elif  __GNUC__

        int edx=0;
        try 
        {
                asm(
                                "mov 1,%%eax \n" //Get ready for CPUID
                                "CPUID \n" //Access CPUID
                                :"=d"(edx) 
                         );
        }
        catch(...) //Catch all
        {
                return false;
        }
        if (edx & 0x800000)
        {
                try{ asm("emms"); }
                catch(...) {return false;}
        }
        else
                return false;
        
        return true;
#elif __BORLANDC__

//This is for detecting assembly when using the Borland compilers
//If you do not have TASM then this will not compile
//If you do have TASM then uncomment the code below, otherwise ignore it

        #ifdef USE_TASM
        int RegEDX=0;
        try
  {
        asm
    {
        mov eax, 1
      CPUID
      mov RegEDX, edx
    }
  }
  catch(...) {return false;}

  if (RegEDX & 0x800000)
  {
        try{asm{emms}}
                catch(...) {return false;}
  }
  else
        return false;
  return true;
#else

        std::cout<<"Support to detect this has not been compiled in.  Please check source(detect_mmx.cpp)"<<std::endl;
  return false;
#endif //Endif USE_TASM

#else

        cl_info(0, "CL_System::detect_mmx() not implemented under your OS/Compiler/Architecture.");
        return false;

#endif

#else
        return false;
#endif //End USE_I386_ASSEMBLER
}

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