1 files changed, 73 insertions, 0 deletions
diff --git a/libstdc++-v3/config/cpu/i386/atomicity.h b/libstdc++-v3/config/cpu/i386/atomicity.h
new file mode 100644
index 000000000..97205e42f
--- /dev/null
+++ b/libstdc++-v3/config/cpu/i386/atomicity.h
@@ -0,0 +1,73 @@
+// Low-level functions for atomic operations: x86, x >= 3 version  -*- C++ -*-
+
+// Copyright (C) 2003, 2004, 2005, 2009 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, 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 General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+#include <ext/atomicity.h>
+
+namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  template<int __inst>
+    struct _Atomicity_lock
+    {
+      static volatile _Atomic_word _S_atomicity_lock;
+    };
+
+  template<int __inst>
+  volatile _Atomic_word _Atomicity_lock<__inst>::_S_atomicity_lock = 0;
+
+  template volatile _Atomic_word _Atomicity_lock<0>::_S_atomicity_lock;
+  
+  _Atomic_word 
+  __attribute__ ((__unused__))
+  __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
+  {
+    register _Atomic_word __result, __tmp = 1;
+    
+    // Obtain the atomic exchange/add spin lock.
+    do 
+      {
+	__asm__ __volatile__ ("xchg{l} {%0,%1|%1,%0}"
+			      : "=m" (_Atomicity_lock<0>::_S_atomicity_lock),
+			      "+r" (__tmp)
+			      : "m" (_Atomicity_lock<0>::_S_atomicity_lock));
+      } 
+    while (__tmp);
+    
+    __result = *__mem;
+    *__mem += __val;
+    
+    // Release spin lock.
+    _Atomicity_lock<0>::_S_atomicity_lock = 0;
+    
+    return __result;
+  }
+  
+  void
+  __attribute__ ((__unused__))
+  __atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
+  { __exchange_and_add(__mem, __val); }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace