#include <luna/DebugLog.h>
#include <luna/Spinlock.h>

#ifdef ARCH_X86_64
#define pause() asm volatile("pause")
#else
#error "Unsupported architecture"
#endif

void Spinlock::lock()
{
    int expected = 0;
    while (!m_lock.compare_exchange_strong(expected, 1))
    {
        expected = 0;
        pause();
    }
}

bool Spinlock::try_lock()
{
    int expected = 0;
    return m_lock.compare_exchange_strong(expected, 1);
}

void Spinlock::unlock()
{
    int expected = 1;
    if (!m_lock.compare_exchange_strong(expected, 0))
    {
        dbgln("Spinlock::unlock() called on an unlocked lock with value %d", expected);
    }
}

ScopeLock::ScopeLock(Spinlock& lock) : m_lock(lock)
{
    m_lock.lock();
}

ScopeLock::~ScopeLock()
{
    if (!m_taken_over) m_lock.unlock();
}

const u32 RETRIES = 5000000;

SafeScopeLock::SafeScopeLock(Spinlock& lock) : m_lock(lock)
{
    u32 tries_left = RETRIES;
    while (!lock.try_lock() && --tries_left) { pause(); }

    if (tries_left) m_success = true;
}

SafeScopeLock::~SafeScopeLock()
{
    if (m_success) m_lock.unlock();
}