L4Re - L4 Runtime Environment
atomic.h
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1 
5 /*
6  * (c) 2004-2009 Adam Lackorzynski <adam@os.inf.tu-dresden.de>,
7  * Alexander Warg <warg@os.inf.tu-dresden.de>
8  * economic rights: Technische Universit├Ąt Dresden (Germany)
9  *
10  * This file is part of TUD:OS and distributed under the terms of the
11  * GNU General Public License 2.
12  * Please see the COPYING-GPL-2 file for details.
13  *
14  * As a special exception, you may use this file as part of a free software
15  * library without restriction. Specifically, if other files instantiate
16  * templates or use macros or inline functions from this file, or you compile
17  * this file and link it with other files to produce an executable, this
18  * file does not by itself cause the resulting executable to be covered by
19  * the GNU General Public License. This exception does not however
20  * invalidate any other reasons why the executable file might be covered by
21  * the GNU General Public License.
22  */
23 
24 #ifndef L4_CXX_ATOMIC_H__
25 #define L4_CXX_ATOMIC_H__
26 
27 #include <l4/util/atomic.h>
28 
29 extern "C" void ____error_compare_and_swap_does_not_support_3_bytes____();
30 extern "C" void ____error_compare_and_swap_does_not_support_more_than_4_bytes____();
31 
32 namespace L4
33 {
34  template< typename X >
35  inline int compare_and_swap(X volatile *dst, X old_val, X new_val)
36  {
37  switch (sizeof(X))
38  {
39  case 1:
40  return l4util_cmpxchg8((l4_uint8_t volatile*)dst, old_val, new_val);
41  case 2:
42  return l4util_cmpxchg16((l4_uint16_t volatile *)dst, old_val, new_val);
43  case 3: ____error_compare_and_swap_does_not_support_3_bytes____();
44  case 4:
45  return l4util_cmpxchg32((l4_uint32_t volatile*)dst, old_val, new_val);
46  default:
47  ____error_compare_and_swap_does_not_support_more_than_4_bytes____();
48  }
49  return 0;
50  }
51 };
52 
53 #endif // L4_CXX_ATOMIC_H__
unsigned short int l4_uint16_t
Unsigned 16bit value.
Definition: l4int.h:38
L4 low-level kernel interface.
Definition: alloc.h:27
int l4util_cmpxchg32(volatile l4_uint32_t *dest, l4_uint32_t cmp_val, l4_uint32_t new_val)
Atomic compare and exchange (32 bit version)
Definition: atomic.h:311
int l4util_cmpxchg8(volatile l4_uint8_t *dest, l4_uint8_t cmp_val, l4_uint8_t new_val)
Atomic compare and exchange (8 bit version)
Definition: atomic.h:327
atomic operations header and generic implementations
unsigned char l4_uint8_t
Unsigned 8bit value.
Definition: l4int.h:36
int l4util_cmpxchg16(volatile l4_uint16_t *dest, l4_uint16_t cmp_val, l4_uint16_t new_val)
Atomic compare and exchange (16 bit version)
Definition: atomic.h:319
unsigned int l4_uint32_t
Unsigned 32bit value.
Definition: l4int.h:40