#include <sync.h>


void spinlock_init(spinlock_t* lock)
{
  lock->locked = 0;
}

static inline int atomic_xchg(volatile int* addr, int newval)
{
  int result;

  asm volatile (
    "xchg %0, %1"
    : "=r"(result), "+m"(*addr)
    : "0"(newval)
    : "memory"
  );

  return result;
}

void spin_lock(spinlock_t* lock)
{
  while (atomic_xchg(&lock->locked, 1))
  {
    while (lock->locked)
    {
      asm volatile("pause");
    }
  }
}

void spin_unlock(spinlock_t* lock)
{
  __atomic_clear(&lock->locked, __ATOMIC_RELEASE);
}