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+/*
+ * ptw32_InterlockedCompareExchange.c
+ *
+ * Description:
+ * This translation unit implements routines which are private to
+ * the implementation and may be used throughout it.
+ *
+ * --------------------------------------------------------------------------
+ *
+ * Pthreads-win32 - POSIX Threads Library for Win32
+ * Copyright(C) 1998 John E. Bossom
+ * Copyright(C) 1999,2002 Pthreads-win32 contributors
+ *
+ * Contact Email: rpj@ise.canberra.edu.au
+ *
+ * The current list of contributors is contained
+ * in the file CONTRIBUTORS included with the source
+ * code distribution. The list can also be seen at the
+ * following World Wide Web location:
+ * http://sources.redhat.com/pthreads-win32/contributors.html
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library in the file COPYING.LIB;
+ * if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include "pthread.h"
+#include "implement.h"
+
+
+/*
+ * ptw32_InterlockedCompareExchange --
+ *
+ * Needed because W95 doesn't support InterlockedCompareExchange.
+ * It is only used when running the dll on W95. Other versions of
+ * Windows use the Win32 supported version, which may be running on
+ * different processor types.
+ *
+ * This can't be inlined because we need to know it's address so that
+ * we can call it through a pointer.
+ */
+PTW32_INTERLOCKED_LONG WINAPI
+ptw32_InterlockedCompareExchange(PTW32_INTERLOCKED_LPLONG location,
+ PTW32_INTERLOCKED_LONG value,
+ PTW32_INTERLOCKED_LONG comparand)
+{
+ PTW32_INTERLOCKED_LONG result;
+
+#if defined(_M_IX86) || defined(_X86_)
+
+#if defined(_MSC_VER)
+
+ _asm {
+ PUSH ecx
+ PUSH edx
+ MOV ecx,dword ptr [location]
+ MOV edx,dword ptr [value]
+ MOV eax,dword ptr [comparand]
+ LOCK CMPXCHG dword ptr [ecx],edx ; if (EAX == [ECX]),
+ ; [ECX] = EDX
+ ; else
+ ; EAX = [ECX]
+ MOV dword ptr [result], eax
+ POP edx
+ POP ecx
+ }
+
+#elif defined(__GNUC__)
+
+ __asm__
+ (
+ "lock\n\t"
+ "cmpxchgl %3,(%0)" /* if (EAX == [location]), */
+ /* [location] = value */
+ /* else */
+ /* EAX = [location] */
+ :"=r" (location), "=a" (result)
+ :"0" (location), "q" (value), "a" (comparand)
+ : "memory" );
+
+#endif
+
+#else
+
+ /*
+ * If execution gets to here then we should be running on a Win95 system
+ * but either running on something other than an X86 processor, or a
+ * compiler other than MSVC or GCC. Pthreads-win32 doesn't support that
+ * platform (yet).
+ */
+
+ result = 0;
+
+#endif
+
+ return result;
+}