rt-thread-official/components/external/SQLite-3.8.1/src/hwtime.h

86 lines
2.3 KiB
C

/*
** 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 _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_) */