src/hwtime.h

   1 /*
   2 ** 2008 May 27
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 ******************************************************************************
  12 **
  13 ** This file contains inline asm code for retrieving "high-performance"
  14 ** counters for x86 and x86_64 class CPUs.
  15 */
  16 #ifndef SQLITE_HWTIME_H
  17 #define SQLITE_HWTIME_H
  18
  19 /*
  20 ** The following routine only works on Pentium-class (or newer) processors.
  21 ** It uses the RDTSC opcode to read the cycle count value out of the
  22 ** processor and returns that value.  This can be used for high-res
  23 ** profiling.
  24 */
  25 #if !defined(__STRICT_ANSI__) && \
  26     (defined(__GNUC__) || defined(_MSC_VER)) && \
  27     (defined(i386) || defined(__i386__) || defined(_M_IX86))
  28
  29   #if defined(__GNUC__)
  30
  31   __inline__ sqlite_uint64 sqlite3Hwtime(void){
  32      unsigned int lo, hi;
  33      __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
  34      return (sqlite_uint64)hi << 32 | lo;
  35   }
  36
  37   #elif defined(_MSC_VER)
  38
  39   __declspec(naked) __inline sqlite_uint64 __cdecl sqlite3Hwtime(void){
  40      __asm {
  41         rdtsc
  42         ret       ; return value at EDX:EAX
  43      }
  44   }
  45
  46   #endif
  47
  48 #elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__x86_64__))
  49
  50   __inline__ sqlite_uint64 sqlite3Hwtime(void){
  51      unsigned int lo, hi;
  52      __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
  53      return (sqlite_uint64)hi << 32 | lo;
  54   }
  55
  56 #elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__ppc__))
  57
  58   __inline__ sqlite_uint64 sqlite3Hwtime(void){
  59       unsigned long long retval;
  60       unsigned long junk;
  61       __asm__ __volatile__ ("\n\
  62           1:      mftbu   %1\n\
  63                   mftb    %L0\n\
  64                   mftbu   %0\n\
  65                   cmpw    %0,%1\n\
  66                   bne     1b"
  67                   : "=r" (retval), "=r" (junk));
  68       return retval;
  69   }
  70
  71 #else
  72
  73   /*
  74   ** asm() is needed for hardware timing support.  Without asm(),
  75   ** disable the sqlite3Hwtime() routine.
  76   **
  77   ** sqlite3Hwtime() is only used for some obscure debugging
  78   ** and analysis configurations, not in any deliverable, so this
  79   ** should not be a great loss.
  80   */
  81   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }
  82
  83 #endif
  84
  85 #endif /* !defined(SQLITE_HWTIME_H) */