1. 根目录:
2. arch
3. h8300
4. include
5. asm
6. cmpxchg.h

#ifndef __ARCH_H8300_CMPXCHG__
#define __ARCH_H8300_CMPXCHG__

#include <linux/irqflags.h>

#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))

struct __xchg_dummy { unsigned long a[100]; };
#define __xg(x) ((volatile struct __xchg_dummy *)(x))

static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
{
  unsigned long tmp, flags;

  local_irq_save(flags);

  switch (size) {
  case 1:
    __asm__ __volatile__
    ("mov.b %2,%0\n\t"
     "mov.b %1,%2"
    : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
    break;
  case 2:
    __asm__ __volatile__
    ("mov.w %2,%0\n\t"
     "mov.w %1,%2"
    : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
    break;
  case 4:
    __asm__ __volatile__
    ("mov.l %2,%0\n\t"
     "mov.l %1,%2"
    : "=&r" (tmp) : "r" (x), "m" (*__xg(ptr)) : "memory");
    break;
  default:
    tmp = 0;	  
  }
  local_irq_restore(flags);
  return tmp;
}

#include <asm-generic/cmpxchg-local.h>

/*
 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 * them available.
 */
#define cmpxchg_local(ptr, o, n)				  	       \
	((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
			(unsigned long)(n), sizeof(*(ptr))))
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))

#ifndef CONFIG_SMP
#include <asm-generic/cmpxchg.h>
#endif

#define atomic_xchg(v, new) (xchg(&((v)->counter), new))

#endif /* __ARCH_H8300_CMPXCHG__ */