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Diffstat (limited to 'src/threading/atomic.h')
| -rw-r--r-- | src/threading/atomic.h | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/threading/atomic.h b/src/threading/atomic.h new file mode 100644 index 000000000..c9a454f20 --- /dev/null +++ b/src/threading/atomic.h @@ -0,0 +1,139 @@ +/* +Minetest +Copyright (C) 2015 ShadowNinja <shadowninja@minetest.net> + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU Lesser General Public License as published by +the Free Software Foundation; either version 2.1 of the License, or +(at your option) any later version. + +This program 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 Lesser General Public License for more details. + +You should have received a copy of the GNU Lesser General Public License along +with this program; if not, write to the Free Software Foundation, Inc., +51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#ifndef THREADING_ATOMIC_H +#define THREADING_ATOMIC_H + + +#if __cplusplus >= 201103L + #include <atomic> + template<typename T> using Atomic = std::atomic<T>; + template<typename T> using GenericAtomic = std::atomic<T>; +#else + +#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) +#define CLANG_VERSION (__clang_major__ * 100 + __clang_minor__) +#if GCC_VERSION >= 407 || CLANG_VERSION >= 302 + #define ATOMIC_LOAD_GENERIC(T, v) do { \ + T _val; \ + __atomic_load(&(v), &(_val), __ATOMIC_SEQ_CST); \ + return _val; \ + } while(0) + #define ATOMIC_LOAD(T, v) return __atomic_load_n (&(v), __ATOMIC_SEQ_CST) + #define ATOMIC_STORE(T, v, x) __atomic_store (&(v), &(x), __ATOMIC_SEQ_CST); return x + #define ATOMIC_EXCHANGE(T, v, x) return __atomic_exchange (&(v), &(x), __ATOMIC_SEQ_CST) + #define ATOMIC_ADD_EQ(T, v, x) return __atomic_add_fetch (&(v), (x), __ATOMIC_SEQ_CST) + #define ATOMIC_SUB_EQ(T, v, x) return __atomic_sub_fetch (&(v), (x), __ATOMIC_SEQ_CST) + #define ATOMIC_POST_INC(T, v) return __atomic_fetch_add (&(v), 1, __ATOMIC_SEQ_CST) + #define ATOMIC_POST_DEC(T, v) return __atomic_fetch_sub (&(v), 1, __ATOMIC_SEQ_CST) + #define ATOMIC_CAS(T, v, e, d) return __atomic_compare_exchange(&(v), &(e), &(d), \ + false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) +#else + #define ATOMIC_USE_LOCK + #include "threading/mutex.h" + + #define ATOMIC_LOCK_OP(T, op) do { \ + m_mutex.lock(); \ + T _val = (op); \ + m_mutex.unlock(); \ + return _val; \ + } while (0) + #define ATOMIC_LOCK_CAS(T, v, e, d) do { \ + m_mutex.lock(); \ + bool _eq = (v == e); \ + if (_eq) \ + v = d; \ + m_mutex.unlock(); \ + return _eq; \ + } while (0) + #define ATOMIC_LOAD(T, v) ATOMIC_LOCK_OP(T, v) + #define ATOMIC_LOAD_GENERIC(T, v) ATOMIC_LOAD(T, v) + #define ATOMIC_STORE(T, v, x) ATOMIC_LOCK_OP(T, v = x) + #define ATOMIC_EXCHANGE(T, v, x) do { \ + m_mutex.lock(); \ + T _val = v; \ + v = x; \ + m_mutex.unlock(); \ + return _val; \ + } while (0) + #if GCC_VERSION >= 401 + #define ATOMIC_ADD_EQ(T, v, x) return __sync_add_and_fetch(&(v), (x)) + #define ATOMIC_SUB_EQ(T, v, x) return __sync_sub_and_fetch(&(v), (x)) + #define ATOMIC_POST_INC(T, v) return __sync_fetch_and_add(&(v), 1) + #define ATOMIC_POST_DEC(T, v) return __sync_fetch_and_sub(&(v), 1) + #define ATOMIC_CAS(T, v, e, d) return __sync_bool_compare_and_swap(&(v), &(e), (d)) + #else + #define ATOMIC_ADD_EQ(T, v, x) ATOMIC_LOCK_OP(T, v += x) + #define ATOMIC_SUB_EQ(T, v, x) ATOMIC_LOCK_OP(T, v -= x) + #define ATOMIC_POST_INC(T, v) ATOMIC_LOCK_OP(T, v++) + #define ATOMIC_POST_DEC(T, v) ATOMIC_LOCK_OP(T, v--) + #define ATOMIC_CAS(T, v, e, d) ATOMIC_LOCK_CAS(T, v, e, d) + #endif +#endif + +// For usage with integral types. +template<typename T> +class Atomic { +public: + Atomic(const T &v = 0) : m_val(v) {} + + operator T () { ATOMIC_LOAD(T, m_val); } + + T exchange(T x) { ATOMIC_EXCHANGE(T, m_val, x); } + bool compare_exchange_strong(T &expected, T desired) { ATOMIC_CAS(T, m_val, expected, desired); } + + T operator = (T x) { ATOMIC_STORE(T, m_val, x); } + T operator += (T x) { ATOMIC_ADD_EQ(T, m_val, x); } + T operator -= (T x) { ATOMIC_SUB_EQ(T, m_val, x); } + T operator ++ () { return *this += 1; } + T operator -- () { return *this -= 1; } + T operator ++ (int) { ATOMIC_POST_INC(T, m_val); } + T operator -- (int) { ATOMIC_POST_DEC(T, m_val); } +private: + T m_val; +#ifdef ATOMIC_USE_LOCK + Mutex m_mutex; +#endif +}; + +// For usage with non-integral types like float for example. +// Needed because the other operations aren't provided by gcc +// for non-integral types: +// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/_005f_005fatomic-Builtins.html +template<typename T> +class GenericAtomic { +public: + GenericAtomic(const T &v = 0) : m_val(v) {} + + operator T () { ATOMIC_LOAD_GENERIC(T, m_val); } + + T exchange(T x) { ATOMIC_EXCHANGE(T, m_val, x); } + bool compare_exchange_strong(T &expected, T desired) { ATOMIC_CAS(T, m_val, expected, desired); } + + T operator = (T x) { ATOMIC_STORE(T, m_val, x); } +private: + T m_val; +#ifdef ATOMIC_USE_LOCK + Mutex m_mutex; +#endif +}; + +#endif // C++11 + +#endif |