//This file is a copy used for static linking of Overflow applications. If it is
//part of the Overflow code base, then it is released under the LGPL license.
//For more information, see the COPYING file in the Overflow source directory.

// Copyright (C) 2001 InfoSpace Speech Solutions
// author: Jean-Marc Valin


/* 
   These routines perform automatic detection of the SSE and 3DNow! extensions.
   The first way of doing that is to use the "cpuid" instructions and look for 
   the right bits. The other way is to attempt an SSE or 3DNow! instruction
   and check for an illegal instruction. While, the first method looks cleaner,
   the second method is prefered here because it is possible for the CPU to
   support SSE, while the OS doesn't support it. In this case, by only checking 
   the cpuid instruction, you think you can use SSE, while in fact you can't.
   
   SSE (SIMD Streaming Extensions) requires at least Linux 2.4 or Win NT SP6 
   (I don't know about millenium/2000/XP). It is not yet supported on Solaris/x86.
   To compile C/C++ code with SSE assembly on MSVC++, you need the compiler 
   "processor pack". A recent version of binutils (2.10 I think) is required 
   under Linux (that should not be a problem).

   3DNow! does not require OS support, as it is only an extension to MMX.
*/

#include "iextensions.h"
#include <iostream>

using namespace std;

namespace FD {

//@implements core

bool IExtensions::isse=false;
bool IExtensions::i3dnow=false;


void IExtensions::detect()
{
   detectSSE();
   detect3DNow();
}


#ifdef __GNUC__

#if defined (_ENABLE_SSE) || defined (_ENABLE_3DNOW)

#include <setjmp.h>
#include <signal.h>

static jmp_buf env;

/*Catches illegal instructions for SSE/3DNow! checks*/
static void illegal_inst(int sig)
{
   signal (SIGILL, SIG_DFL);
   longjmp(env,1);
}
#endif

#ifdef _ENABLE_SSE
#define CHECK_SSE
void IExtensions::detectSSE()
{
   if (setjmp(env))
   {
      //cerr << "SSE not detected\n";
      isse=false;
      return;
   }
   signal (SIGILL, illegal_inst);
   __asm__ __volatile__ (
      "\txorps %%xmm0, %%xmm0 \n"
      : :
      : "memory"
      );
   signal (SIGILL, SIG_DFL);
   isse=true;
   //cerr << "SSE detected\n";
}
#endif /*_ENABLE_SSE*/

#ifdef _ENABLE_3DNOW
#define CHECK_3DNOW
void IExtensions::detect3DNow()
{
   if (setjmp(env))
   {
      //cerr << "3DNow! not detected\n";
      i3dnow=false;
      return;
   }
   signal (SIGILL, illegal_inst);
   __asm__ __volatile__ (
	"\tpfadd %%mm7, %%mm7 \n"
        "\tfemms \n"
        : : 
	: "st", "st(1)", "st(2)", "st(3)", "st(4)", "st(5)", "st(6)", "st(7)", "memory"
        );
   signal (SIGILL, SIG_DFL);
   i3dnow=true;
   //cerr << "3DNow! detected\n";
}

#endif

#elif defined (WIN32)

#include <excpt.h>

#define STATUS_ILLEGAL_INSTRUCTION       0xC000001DL

/* SSE detection (and hence 3DNow! too) taken from example in Intel's guide*/

#ifdef _ENABLE_SSE
#define CHECK_SSE
void IExtensions::detectSSE()
{
   _try {
      _asm {
	 
	 xorps xmm0, xmm0
	    
	    }
   }
   _except(EXCEPTION_EXECUTE_HANDLER)
      {
	 //fprintf(stdout, "In catch\n");
	 if (_exception_code()==STATUS_ILLEGAL_INSTRUCTION)
	 {
	    //cerr << "SSE not detected\n";
	    isse=false;
	    return;
	 }
      }
   //cerr << "SSE detected\n";
   isse=true;
}
#endif


#ifdef _ENABLE_3DNOW
#define CHECK_3DNOW
void IExtensions::detect3DNow()
{
   _try {
      _asm {
	 
	 pfadd mm7 mm7
	 femms
	    
	    }
   }
   _except(EXCEPTION_EXECUTE_HANDLER)
      {
	 //fprintf(stdout, "In catch\n");
	 if (_exception_code()==STATUS_ILLEGAL_INSTRUCTION)
	 {
	    //cerr << "3DNow! not detected\n";
	    i3dnow=false;
	    return;
	 }
      }
   //cerr << "3DNow! detected\n";
   i3dnow=true;

}
#endif

#else /*WIN32*/


#if (defined (_ENABLE_SSE) || defined (_ENABLE_3DNOW))
#error "SSE and 3DNow! only supported on GCC and MSVC++ (help us get more support). Try disabling _ENABLE_SSE and _ENABLE_3DNOW"
#endif

#endif


#ifndef CHECK_SSE
void IExtensions::detectSSE()
{
   isse=false;
}
#endif /*CHECK_SSE*/

#ifndef CHECK_3DNOW

void IExtensions::detect3DNow()
{
   i3dnow=false;
}

}//namespace FD

#endif /*CHECK_3DNOW*/