text: #ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
  #define __ASM_GENERIC_CMPXCHG_LOCAL_H
  
  #include <os/types.h>
  #include <os/irqflags.h>
  
  extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
  	__noreturn;
  
  /*
   * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
   * long parameter, supporting various types of architectures.
   */
  static inline unsigned long __cmpxchg_local_generic(volatile void *ptr,
  		unsigned long old, unsigned long new, int size)
  {
  	unsigned long flags, prev;
  
  	/*
  	 * Sanity checking, compile-time.
  	 */
  	if (size == 8 && sizeof(unsigned long) != 8)
  		wrong_size_cmpxchg(ptr);
  
  	raw_local_irq_save(flags);
  	switch (size) {
  	case 1: prev = *(u8 *)ptr;
  		if (prev == old)
  			*(u8 *)ptr = (u8)new;
  		break;
  	case 2: prev = *(u16 *)ptr;
  		if (prev == old)
  			*(u16 *)ptr = (u16)new;
  		break;
  	case 4: prev = *(u32 *)ptr;
  		if (prev == old)
  			*(u32 *)ptr = (u32)new;
  		break;
  	case 8: prev = *(u64 *)ptr;
  		if (prev == old)
  			*(u64 *)ptr = (u64)new;
  		break;
  	default:
  		wrong_size_cmpxchg(ptr);
  	}
  	raw_local_irq_restore(flags);
  	return prev;
  }
  
  /*
   * Generic version of __cmpxchg64_local. Takes an u64 parameter.
   */
  static inline u64 __cmpxchg64_local_generic(volatile void *ptr,
  		u64 old, u64 new)
  {
  	u64 prev;
  	unsigned long flags;
  
  	raw_local_irq_save(flags);
  	prev = *(u64 *)ptr;
  	if (prev == old)
  		*(u64 *)ptr = new;
  	raw_local_irq_restore(flags);
  	return prev;
  }
  
  #endif
  