/*

 ** 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_) */