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** 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.

#ifndef SQLITE_HWTIME_H

#define SQLITE_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(SQLITE_HWTIME_H) */