*** thread_nt.h	Fri Oct 26 21:03:09 2007
--- Python-2.5.1/Python/thread_nt.h	Fri Oct 26 21:03:34 2007
***************
*** 1,9 ****
--- 1,10 ----
  
  /* This code implemented by Dag.Gruneau@elsa.preseco.comm.se */
  /* Fast NonRecursiveMutex support by Yakov Markovitch, markovitch@iso.ru */
  /* Eliminated some memory leaks, gsw@agere.com */
+ /* Nixed InterlockedCompareExchange emulation (x86_64:1, Win95:0), warren@delsci.com */
  
  #include <windows.h>
  #include <limits.h>
  #ifdef HAVE_PROCESS_H
  #include <process.h>
***************
*** 13,88 ****
  	LONG   owned ;
  	DWORD  thread_id ;
  	HANDLE hevent ;
  } NRMUTEX, *PNRMUTEX ;
  
- typedef PVOID WINAPI interlocked_cmp_xchg_t(PVOID *dest, PVOID exc, PVOID comperand) ;
- 
- /* Sorry mate, but we haven't got InterlockedCompareExchange in Win95! */
- static PVOID WINAPI
- interlocked_cmp_xchg(PVOID *dest, PVOID exc, PVOID comperand)
- {
- 	static LONG spinlock = 0 ;
- 	PVOID result ;
- 	DWORD dwSleep = 0;
- 
- 	/* Acqire spinlock (yielding control to other threads if cant aquire for the moment) */
- 	while(InterlockedExchange(&spinlock, 1))
- 	{
- 		// Using Sleep(0) can cause a priority inversion.
- 		// Sleep(0) only yields the processor if there's
- 		// another thread of the same priority that's
- 		// ready to run.  If a high-priority thread is
- 		// trying to acquire the lock, which is held by
- 		// a low-priority thread, then the low-priority
- 		// thread may never get scheduled and hence never
- 		// free the lock.  NT attempts to avoid priority
- 		// inversions by temporarily boosting the priority
- 		// of low-priority runnable threads, but the problem
- 		// can still occur if there's a medium-priority
- 		// thread that's always runnable.  If Sleep(1) is used,
- 		// then the thread unconditionally yields the CPU.  We
- 		// only do this for the second and subsequent even
- 		// iterations, since a millisecond is a long time to wait
- 		// if the thread can be scheduled in again sooner
- 		// (~100,000 instructions).
- 		// Avoid priority inversion: 0, 1, 0, 1,...
- 		Sleep(dwSleep);
- 		dwSleep = !dwSleep;
- 	}
- 	result = *dest ;
- 	if (result == comperand)
- 		*dest = exc ;
- 	/* Release spinlock */
- 	spinlock = 0 ;
- 	return result ;
- } ;
- 
- static interlocked_cmp_xchg_t *ixchg;
- 
  BOOL
  InitializeNonRecursiveMutex(PNRMUTEX mutex)
  {
- 	if (!ixchg)
- 	{
- 		/* Sorely, Win95 has no InterlockedCompareExchange API (Win98 has), so we have to use emulation */
- 		HANDLE kernel = GetModuleHandle("kernel32.dll") ;
- 		if (!kernel || (ixchg = (interlocked_cmp_xchg_t *)GetProcAddress(kernel, "InterlockedCompareExchange")) == NULL)
- 			ixchg = interlocked_cmp_xchg ;
- 	}
- 
  	mutex->owned = -1 ;  /* No threads have entered NonRecursiveMutex */
  	mutex->thread_id = 0 ;
  	mutex->hevent = CreateEvent(NULL, FALSE, FALSE, NULL) ;
  	return mutex->hevent != NULL ;	/* TRUE if the mutex is created */
  }
  
- #ifdef InterlockedCompareExchange
- #undef InterlockedCompareExchange
- #endif
- #define InterlockedCompareExchange(dest,exchange,comperand) (ixchg((dest), (exchange), (comperand)))
- 
  VOID
  DeleteNonRecursiveMutex(PNRMUTEX mutex)
  {
  	/* No in-use check */
  	CloseHandle(mutex->hevent) ;
--- 14,32 ----
***************
*** 96,106 ****
  	DWORD ret ;
  
  	/* InterlockedIncrement(&mutex->owned) == 0 means that no thread currently owns the mutex */
  	if (!wait)
  	{
! 		if (InterlockedCompareExchange((PVOID *)&mutex->owned, (PVOID)0, (PVOID)-1) != (PVOID)-1)
  			return WAIT_TIMEOUT ;
  		ret = WAIT_OBJECT_0 ;
  	}
  	else
  		ret = InterlockedIncrement(&mutex->owned) ?
--- 40,50 ----
  	DWORD ret ;
  
  	/* InterlockedIncrement(&mutex->owned) == 0 means that no thread currently owns the mutex */
  	if (!wait)
  	{
! 		if (InterlockedCompareExchange(&mutex->owned, 0, -1) != -1)
  			return WAIT_TIMEOUT ;
  		ret = WAIT_OBJECT_0 ;
  	}
  	else
  		ret = InterlockedIncrement(&mutex->owned) ?