/*

** 2008 May 27

**

** The author disclaims copyright to this source code.  In place of

** a legal notice, here is a blessing:

**

**    May you do good and not evil.

**    May you find forgiveness for yourself and forgive others.

**    May you share freely, never taking more than you give.

**

******************************************************************************

**

** This file contains inline asm code for retrieving "high-performance"

** counters for x86 class CPUs.

**

** $Id: hwtime.h,v 1.3 2008/08/01 14:33:15 shane Exp $

*/

#ifndef _HWTIME_H_

#define _HWTIME_H_

/*

** The following routine only works on pentium-class (or newer) processors.

** It uses the RDTSC opcode to read the cycle count value out of the

** processor and returns that value.  This can be used for high-res

** profiling.

*/

#if (defined(__GNUC__) || defined(_MSC_VER)) && \

      (defined(i386) || defined(__i386__) || defined(_M_IX86))

  #if defined(__GNUC__)

  __inline__ sqlite_uint64 sqlite3Hwtime(void){

     unsigned int lo, hi;

     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));

     return (sqlite_uint64)hi << 32 | lo;

  }

  #elif defined(_MSC_VER)

  __declspec(naked) __inline sqlite_uint64 __cdecl sqlite3Hwtime(void){

     __asm {

        rdtsc

        ret       ; return value at EDX:EAX

     }

  }

  #endif

#elif (defined(__GNUC__) && defined(__x86_64__))

  __inline__ sqlite_uint64 sqlite3Hwtime(void){

      unsigned long val;

      __asm__ __volatile__ ("rdtsc" : "=A" (val));

      return val;

  }

#elif (defined(__GNUC__) && defined(__ppc__))

  __inline__ sqlite_uint64 sqlite3Hwtime(void){

      unsigned long long retval;

      unsigned long junk;

      __asm__ __volatile__ ("\n\

          1:      mftbu   %1\n\

                  mftb    %L0\n\

                  mftbu   %0\n\

                  cmpw    %0,%1\n\

                  bne     1b"

                  : "=r" (retval), "=r" (junk));

      return retval;

  }

#else

  #error Need implementation of sqlite3Hwtime() for your platform.

  /*

  ** To compile without implementing sqlite3Hwtime() for your platform,

  ** you can remove the above #error and use the following

  ** stub function.  You will lose timing support for many

  ** of the debugging and testing utilities, but it should at

  ** least compile and run.

  */

  sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }

#endif

#endif /* !defined(_HWTIME_H_) */