83 lines
2.6 KiB
C++
83 lines
2.6 KiB
C++
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// Copyright Oliver Kowalke 2016.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_FIBERS_DETAIL_CPU_RELAX_H
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#define BOOST_FIBERS_DETAIL_CPU_RELAX_H
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#include <chrono>
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#include <thread>
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#include <boost/config.hpp>
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#include <boost/predef.h>
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#include <boost/fiber/detail/config.hpp>
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#if BOOST_COMP_MSVC || BOOST_COMP_MSVC_EMULATED
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# include <windows.h>
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#endif
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#ifdef BOOST_HAS_ABI_HEADERS
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# include BOOST_ABI_PREFIX
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#endif
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namespace boost {
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namespace fibers {
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namespace detail {
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#if BOOST_ARCH_ARM
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# if BOOST_COMP_MSVC
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# define cpu_relax() YieldProcessor();
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# elif (defined(__ARM_ARCH_6K__) || \
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defined(__ARM_ARCH_6Z__) || \
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defined(__ARM_ARCH_6ZK__) || \
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defined(__ARM_ARCH_6T2__) || \
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defined(__ARM_ARCH_7__) || \
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defined(__ARM_ARCH_7A__) || \
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defined(__ARM_ARCH_7R__) || \
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defined(__ARM_ARCH_7M__) || \
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defined(__ARM_ARCH_7S__) || \
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defined(__ARM_ARCH_8A__) || \
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defined(__aarch64__))
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// http://groups.google.com/a/chromium.org/forum/#!msg/chromium-dev/YGVrZbxYOlU/Vpgy__zeBQAJ
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// mnemonic 'yield' is supported from ARMv6k onwards
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# define cpu_relax() asm volatile ("yield" ::: "memory");
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# else
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# define cpu_relax() asm volatile ("nop" ::: "memory");
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# endif
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#elif BOOST_ARCH_MIPS && (((__mips_isa_rev > 1) && defined(__mips32)) || ((__mips_isa_rev > 2) && defined(__mips64)))
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# define cpu_relax() asm volatile ("pause" ::: "memory");
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#elif BOOST_ARCH_PPC
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// http://code.metager.de/source/xref/gnu/glibc/sysdeps/powerpc/sys/platform/ppc.h
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// http://stackoverflow.com/questions/5425506/equivalent-of-x86-pause-instruction-for-ppc
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// mnemonic 'or' shared resource hints
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// or 27, 27, 27 This form of 'or' provides a hint that performance
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// will probably be imrpoved if shared resources dedicated
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// to the executing processor are released for use by other
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// processors
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// extended mnemonics (available with POWER7)
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// yield == or 27, 27, 27
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# define cpu_relax() asm volatile ("or 27,27,27" ::: "memory");
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#elif BOOST_ARCH_X86
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# if BOOST_COMP_MSVC || BOOST_COMP_MSVC_EMULATED
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# define cpu_relax() YieldProcessor();
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# else
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# define cpu_relax() asm volatile ("pause" ::: "memory");
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# endif
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#else
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# define cpu_relax() { \
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static constexpr std::chrono::microseconds us0{ 0 }; \
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std::this_thread::sleep_for( us0); \
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}
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#endif
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}}}
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#ifdef BOOST_HAS_ABI_HEADERS
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# include BOOST_ABI_SUFFIX
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#endif
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#endif // BOOST_FIBERS_DETAIL_CPU_RELAX_H
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