Imported gcc-4.4.3

[msp430-gcc.git] / libstdc++-v3 / include / ext / atomicity.h

diff --git a/libstdc++-v3/include/ext/atomicity.h b/libstdc++-v3/include/ext/atomicity.h
new file mode 100644 (file)
index 0000000..bb891e8
--- /dev/null
+++ b/libstdc++-v3/include/ext/atomicity.h
@@ -0,0 +1,113 @@
+// Support for atomic operations -*- C++ -*-
+
+// Copyright (C) 2004, 2005, 2006, 2008, 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/>.
+
+/** @file atomicity.h
+ *  This is an internal header file, included by other library headers.
+ *  You should not attempt to use it directly.
+ */
+
+#ifndef _GLIBCXX_ATOMICITY_H
+#define _GLIBCXX_ATOMICITY_H   1
+
+#include <bits/c++config.h>
+#include <bits/gthr.h>
+#include <bits/atomic_word.h>
+
+_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
+
+  // Functions for portable atomic access.
+  // To abstract locking primitives across all thread policies, use:
+  // __exchange_and_add_dispatch
+  // __atomic_add_dispatch
+#ifdef _GLIBCXX_ATOMIC_BUILTINS_4
+  static inline _Atomic_word 
+  __exchange_and_add(volatile _Atomic_word* __mem, int __val)
+  { return __sync_fetch_and_add(__mem, __val); }
+
+  static inline void
+  __atomic_add(volatile _Atomic_word* __mem, int __val)
+  { __sync_fetch_and_add(__mem, __val); }
+#else
+  _Atomic_word
+  __attribute__ ((__unused__))
+  __exchange_and_add(volatile _Atomic_word*, int);
+
+  void
+  __attribute__ ((__unused__))
+  __atomic_add(volatile _Atomic_word*, int);
+#endif
+
+  static inline _Atomic_word
+  __exchange_and_add_single(_Atomic_word* __mem, int __val)
+  {
+    _Atomic_word __result = *__mem;
+    *__mem += __val;
+    return __result;
+  }
+
+  static inline void
+  __atomic_add_single(_Atomic_word* __mem, int __val)
+  { *__mem += __val; }
+
+  static inline _Atomic_word
+  __attribute__ ((__unused__))
+  __exchange_and_add_dispatch(_Atomic_word* __mem, int __val)
+  {
+#ifdef __GTHREADS
+    if (__gthread_active_p())
+      return __exchange_and_add(__mem, __val);
+    else
+      return __exchange_and_add_single(__mem, __val);
+#else
+    return __exchange_and_add_single(__mem, __val);
+#endif
+  }
+
+  static inline void
+  __attribute__ ((__unused__))
+  __atomic_add_dispatch(_Atomic_word* __mem, int __val)
+  {
+#ifdef __GTHREADS
+    if (__gthread_active_p())
+      __atomic_add(__mem, __val);
+    else
+      __atomic_add_single(__mem, __val);
+#else
+    __atomic_add_single(__mem, __val);
+#endif
+  }
+
+_GLIBCXX_END_NAMESPACE
+
+// Even if the CPU doesn't need a memory barrier, we need to ensure
+// that the compiler doesn't reorder memory accesses across the
+// barriers.
+#ifndef _GLIBCXX_READ_MEM_BARRIER
+#define _GLIBCXX_READ_MEM_BARRIER __asm __volatile ("":::"memory")
+#endif
+#ifndef _GLIBCXX_WRITE_MEM_BARRIER
+#define _GLIBCXX_WRITE_MEM_BARRIER __asm __volatile ("":::"memory")
+#endif
+
+#endif