text: /*
   * bitops.c: atomic operations which got too long to be inlined all over
   *      the place.
   * 
   * Copyright 1999 Philipp Rumpf (prumpf@tux.org)
   * Copyright 2000 Grant Grundler (grundler@cup.hp.com)
   */
  
  #include <linux/kernel.h>
  #include <linux/spinlock.h>
  #include <asm/system.h>
  #include <asm/atomic.h>
  
  #ifdef CONFIG_SMP
  arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
  	[0 ... (ATOMIC_HASH_SIZE-1)]  = __ARCH_SPIN_LOCK_UNLOCKED
  };
  #endif
  
  #ifdef CONFIG_64BIT
  unsigned long __xchg64(unsigned long x, unsigned long *ptr)
  {
  	unsigned long temp, flags;
  
  	_atomic_spin_lock_irqsave(ptr, flags);
  	temp = *ptr;
  	*ptr = x;
  	_atomic_spin_unlock_irqrestore(ptr, flags);
  	return temp;
  }
  #endif
  
  unsigned long __xchg32(int x, int *ptr)
  {
  	unsigned long flags;
  	long temp;
  
  	_atomic_spin_lock_irqsave(ptr, flags);
  	temp = (long) *ptr;	/* XXX - sign extension wanted? */
  	*ptr = x;
  	_atomic_spin_unlock_irqrestore(ptr, flags);
  	return (unsigned long)temp;
  }
  
  
  unsigned long __xchg8(char x, char *ptr)
  {
  	unsigned long flags;
  	long temp;
  
  	_atomic_spin_lock_irqsave(ptr, flags);
  	temp = (long) *ptr;	/* XXX - sign extension wanted? */
  	*ptr = x;
  	_atomic_spin_unlock_irqrestore(ptr, flags);
  	return (unsigned long)temp;
  }
  
  
  #ifdef CONFIG_64BIT
  unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new)
  {
  	unsigned long flags;
  	unsigned long prev;
  
  	_atomic_spin_lock_irqsave(ptr, flags);
  	if ((prev = *ptr) == old)
  		*ptr = new;
  	_atomic_spin_unlock_irqrestore(ptr, flags);
  	return prev;
  }
  #endif
  
  unsigned long __cmpxchg_u32(volatile unsigned int *ptr, unsigned int old, unsigned int new)
  {
  	unsigned long flags;
  	unsigned int prev;
  
  	_atomic_spin_lock_irqsave(ptr, flags);
  	if ((prev = *ptr) == old)
  		*ptr = new;
  	_atomic_spin_unlock_irqrestore(ptr, flags);
  	return (unsigned long)prev;
  }
  