/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: SpinLock.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <RuntimeInternal.hpp>
#include "SpinLock.hpp"

namespace Aurora::Threading::Primitives
{
    static void YieldCpu(long &count)
    {
        int loops = (1 << count);
        while (loops > 0)
        {
        #if (defined(AURORA_ARCH_X64) || defined(AURORA_ARCH_X86))
            _mm_pause();
        #endif
            loops -= 1;
        }
    }

    SpinLock::SpinLock()
    {
        value_ = 0;
    }

    bool SpinLock::HasOSHandle(AuMach &mach)
    {
        return false;
    }

    bool SpinLock::TryLock()
    {
    #if defined(_AU_HAS_ATOMIC_INTRINS)
        return _interlockedbittestandset(&value_, 0) == 0;
    #else
        return value_.fetch_or(1);
    #endif 
    }

    bool SpinLock::HasLockImplementation()
    {
        return true;
    }

    void SpinLock::Lock()
    {
        auto status = Lock(0);
        SysAssert(status, "Couldn't lock Mutex object");
    }

    bool SpinLock::Lock(AuUInt64 timeout)
    {
        #if defined(_AU_HAS_ATOMIC_INTRINS)
        while (_interlockedbittestandset(&value_, 0))
        #else
        while (value_.fetch_or(1))
        #endif
        {
            long count = 0;
            while (value_)
            {
                YieldCpu(count);
            }
        }

        return true;
    }

    void SpinLock::Unlock()
    {
        value_ = 0;
    }
}