stc/exp/ml_stc_linux_make_v1.0/include/boost/smart_ptr/detail/spinlock_gcc_arm.hpp

   1 #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED\r
   2 #define BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED\r
   3 \r
   4 //\r
   5 //  Copyright (c) 2008 Peter Dimov\r
   6 //\r
   7 //  Distributed under the Boost Software License, Version 1.0.\r
   8 //  See accompanying file LICENSE_1_0.txt or copy at\r
   9 //  http://www.boost.org/LICENSE_1_0.txt)\r
  10 //\r
  11 \r
  12 #include <boost/smart_ptr/detail/yield_k.hpp>\r
  13 \r
  14 namespace boost\r
  15 {\r
  16 \r
  17 namespace detail\r
  18 {\r
  19 \r
  20 class spinlock\r
  21 {\r
  22 public:\r
  23 \r
  24     int v_;\r
  25 \r
  26 public:\r
  27 \r
  28     bool try_lock()\r
  29     {\r
  30         int r;\r
  31 \r
  32         __asm__ __volatile__(\r
  33             "swp %0, %1, [%2]":\r
  34             "=&r"( r ): // outputs\r
  35             "r"( 1 ), "r"( &v_ ): // inputs\r
  36             "memory", "cc" );\r
  37 \r
  38         return r == 0;\r
  39     }\r
  40 \r
  41     void lock()\r
  42     {\r
  43         for( unsigned k = 0; !try_lock(); ++k )\r
  44         {\r
  45             boost::detail::yield( k );\r
  46         }\r
  47     }\r
  48 \r
  49     void unlock()\r
  50     {\r
  51         __asm__ __volatile__( "" ::: "memory" );\r
  52         *const_cast< int volatile* >( &v_ ) = 0;\r
  53     }\r
  54 \r
  55 public:\r
  56 \r
  57     class scoped_lock\r
  58     {\r
  59     private:\r
  60 \r
  61         spinlock & sp_;\r
  62 \r
  63         scoped_lock( scoped_lock const & );\r
  64         scoped_lock & operator=( scoped_lock const & );\r
  65 \r
  66     public:\r
  67 \r
  68         explicit scoped_lock( spinlock & sp ): sp_( sp )\r
  69         {\r
  70             sp.lock();\r
  71         }\r
  72 \r
  73         ~scoped_lock()\r
  74         {\r
  75             sp_.unlock();\r
  76         }\r
  77     };\r
  78 };\r
  79 \r
  80 } // namespace detail\r
  81 } // namespace boost\r
  82 \r
  83 #define BOOST_DETAIL_SPINLOCK_INIT {0}\r
  84 \r
  85 #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_GCC_ARM_HPP_INCLUDED\r