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Diffstat (limited to 'src/third_party/boost-1.56.0/boost/atomic/detail/ops_linux_arm.hpp')
| -rw-r--r-- | src/third_party/boost-1.56.0/boost/atomic/detail/ops_linux_arm.hpp | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/src/third_party/boost-1.56.0/boost/atomic/detail/ops_linux_arm.hpp b/src/third_party/boost-1.56.0/boost/atomic/detail/ops_linux_arm.hpp deleted file mode 100644 index 25167b19742..00000000000 --- a/src/third_party/boost-1.56.0/boost/atomic/detail/ops_linux_arm.hpp +++ /dev/null @@ -1,177 +0,0 @@ -/* - * Distributed under the Boost Software License, Version 1.0. - * (See accompanying file LICENSE_1_0.txt or copy at - * http://www.boost.org/LICENSE_1_0.txt) - * - * Copyright (c) 2009, 2011 Helge Bahmann - * Copyright (c) 2009 Phil Endecott - * Copyright (c) 2013 Tim Blechmann - * Linux-specific code by Phil Endecott - * Copyright (c) 2014 Andrey Semashev - */ -/*! - * \file atomic/detail/ops_linux_arm.hpp - * - * This header contains implementation of the \c operations template. - */ - -#ifndef BOOST_ATOMIC_DETAIL_OPS_LINUX_ARM_HPP_INCLUDED_ -#define BOOST_ATOMIC_DETAIL_OPS_LINUX_ARM_HPP_INCLUDED_ - -#include <boost/memory_order.hpp> -#include <boost/atomic/detail/config.hpp> -#include <boost/atomic/detail/storage_type.hpp> -#include <boost/atomic/detail/operations_fwd.hpp> -#include <boost/atomic/capabilities.hpp> -#include <boost/atomic/detail/ops_cas_based.hpp> -#include <boost/atomic/detail/ops_extending_cas_based.hpp> - -#ifdef BOOST_HAS_PRAGMA_ONCE -#pragma once -#endif - -namespace boost { -namespace atomics { -namespace detail { - -// Different ARM processors have different atomic instructions. In particular, -// architecture versions before v6 (which are still in widespread use, e.g. the -// Intel/Marvell XScale chips like the one in the NSLU2) have only atomic swap. -// On Linux the kernel provides some support that lets us abstract away from -// these differences: it provides emulated CAS and barrier functions at special -// addresses that are guaranteed not to be interrupted by the kernel. Using -// this facility is slightly slower than inline assembler would be, but much -// faster than a system call. -// -// While this emulated CAS is "strong" in the sense that it does not fail -// "spuriously" (i.e.: it never fails to perform the exchange when the value -// found equals the value expected), it does not return the found value on -// failure. To satisfy the atomic API, compare_exchange_{weak|strong} must -// return the found value on failure, and we have to manually load this value -// after the emulated CAS reports failure. This in turn introduces a race -// between the CAS failing (due to the "wrong" value being found) and subsequently -// loading (which might turn up the "right" value). From an application's -// point of view this looks like "spurious failure", and therefore the -// emulated CAS is only good enough to provide compare_exchange_weak -// semantics. - -struct linux_arm_cas_base -{ - static BOOST_FORCEINLINE void fence_before_store(memory_order order) BOOST_NOEXCEPT - { - if ((order & memory_order_release) != 0) - hardware_full_fence(); - } - - static BOOST_FORCEINLINE void fence_after_store(memory_order order) BOOST_NOEXCEPT - { - if (order == memory_order_seq_cst) - hardware_full_fence(); - } - - static BOOST_FORCEINLINE void fence_after_load(memory_order order) BOOST_NOEXCEPT - { - if ((order & (memory_order_consume | memory_order_acquire)) != 0) - hardware_full_fence(); - } - - static BOOST_FORCEINLINE void hardware_full_fence() BOOST_NOEXCEPT - { - typedef void (*kernel_dmb_t)(void); - ((kernel_dmb_t)0xffff0fa0)(); - } -}; - -template< bool Signed > -struct linux_arm_cas : - public linux_arm_cas_base -{ - typedef typename make_storage_type< 4u, Signed >::type storage_type; - - static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order order) BOOST_NOEXCEPT - { - fence_before_store(order); - storage = v; - fence_after_store(order); - } - - static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order order) BOOST_NOEXCEPT - { - storage_type v = storage; - fence_after_load(order); - return v; - } - - static BOOST_FORCEINLINE bool compare_exchange_strong( - storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order success_order, memory_order failure_order) BOOST_NOEXCEPT - { - while (true) - { - storage_type tmp = expected; - if (compare_exchange_weak(storage, tmp, desired, success_order, failure_order)) - return true; - if (tmp != expected) - { - expected = tmp; - return false; - } - } - } - - static BOOST_FORCEINLINE bool compare_exchange_weak( - storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT - { - typedef storage_type (*kernel_cmpxchg32_t)(storage_type oldval, storage_type newval, volatile storage_type* ptr); - - if (((kernel_cmpxchg32_t)0xffff0fc0)(expected, desired, &storage) == 0) - { - return true; - } - else - { - expected = storage; - return false; - } - } - - static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT - { - return true; - } -}; - -template< bool Signed > -struct operations< 1u, Signed > : - public extending_cas_based_operations< cas_based_operations< linux_arm_cas< Signed > >, 1u, Signed > -{ -}; - -template< bool Signed > -struct operations< 2u, Signed > : - public extending_cas_based_operations< cas_based_operations< linux_arm_cas< Signed > >, 2u, Signed > -{ -}; - -template< bool Signed > -struct operations< 4u, Signed > : - public cas_based_operations< linux_arm_cas< Signed > > -{ -}; - -BOOST_FORCEINLINE void thread_fence(memory_order order) BOOST_NOEXCEPT -{ - if (order != memory_order_relaxed) - linux_arm_cas_base::hardware_full_fence(); -} - -BOOST_FORCEINLINE void signal_fence(memory_order order) BOOST_NOEXCEPT -{ - if (order != memory_order_relaxed) - __asm__ __volatile__ ("" ::: "memory"); -} - -} // namespace detail -} // namespace atomics -} // namespace boost - -#endif // BOOST_ATOMIC_DETAIL_OPS_LINUX_ARM_HPP_INCLUDED_ |