// ============================================================================
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// Copyright (c) 2010 Faustino Frechilla
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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/// @file lock_free_atomic_ops.h
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/// @brief This file contains functions to wrap the built-in atomic operations
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/// defined for your compiler
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///
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/// @author Faustino Frechilla
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/// @history
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/// Ref Who When What
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/// Faustino Frechilla 11-Jul-2010 Original development. GCC support
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/// Faustino Frechilla 08-Aug-2014 Change to MIT license
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/// @endhistory
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///
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// ============================================================================
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#ifndef __ATOMIC_OPS_H
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#define __ATOMIC_OPS_H
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#ifdef __GNUC__
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// Atomic functions in GCC are present from version 4.1.0 on
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// http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
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// Test for GCC >= 4.1.0
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#if (__GNUC__ < 4) || \
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((__GNUC__ == 4) && ((__GNUC_MINOR__ < 1) || \
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((__GNUC_MINOR__ == 1) && \
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(__GNUC_PATCHLEVEL__ < 0))) )
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#error Atomic built-in functions are only available in GCC in versions >= 4.1.0
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#endif // end of check for GCC 4.1.0
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/// @brief atomically adds a_count to the variable pointed by a_ptr
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/// @return the value that had previously been in memory
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#define AtomicAdd(a_ptr,a_count) __sync_fetch_and_add (a_ptr, a_count)
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/// @brief atomically substracts a_count from the variable pointed by a_ptr
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/// @return the value that had previously been in memory
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#define AtomicSub(a_ptr,a_count) __sync_fetch_and_sub (a_ptr, a_count)
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/// @brief Compare And Swap
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/// If the current value of *a_ptr is a_oldVal, then write a_newVal into *a_ptr
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/// @return true if the comparison is successful and a_newVal was written
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#define CAS(a_ptr, a_oldVal, a_newVal) __sync_bool_compare_and_swap(a_ptr, a_oldVal, a_newVal)
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/// @brief Compare And Swap
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/// If the current value of *a_ptr is a_oldVal, then write a_newVal into *a_ptr
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/// @return the contents of *a_ptr before the operation
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#define CASVal(a_ptr, a_oldVal, a_newVal) __sync_val_compare_and_swap(a_ptr, a_oldVal, a_newVal)
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#else
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#error Atomic functions such as CAS or AtomicAdd are not defined for your compiler. Please add them in atomic_ops.h
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#endif // __GNUC__
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#endif // __ATOMIC_OPS_H
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