criu/arch/x86/include/asm/atomic.h

#ifndef __CR_ATOMIC_H__
#define __CR_ATOMIC_H__

#include "asm/cmpxchg.h"

#define LOCK_PREFIX "\n\tlock; "

typedef struct {
	int counter;
} atomic_t;

#define ATOMIC_INIT(i)	{ (i) }

static inline int atomic_read(const atomic_t *v)
{
	return (*(volatile int *)&(v)->counter);
}

static inline void atomic_set(atomic_t *v, int i)
{
	v->counter = i;
}

static inline void atomic_add(int i, atomic_t *v)
{
	asm volatile(LOCK_PREFIX "addl %1,%0"
		     : "+m" (v->counter)
		     : "ir" (i));
}

static inline void atomic_sub(int i, atomic_t *v)
{
	asm volatile(LOCK_PREFIX "subl %1,%0"
		     : "+m" (v->counter)
		     : "ir" (i));
}

static inline void atomic_inc(atomic_t *v)
{
	asm volatile(LOCK_PREFIX "incl %0"
		     : "+m" (v->counter));
}

static inline void atomic_dec(atomic_t *v)
{
	asm volatile(LOCK_PREFIX "decl %0"
		     : "+m" (v->counter));
}

static inline int atomic_dec_and_test(atomic_t *v)
{
	unsigned char c;

	asm volatile(LOCK_PREFIX "decl %0; sete %1"
		     : "+m" (v->counter), "=qm" (c)
		     : : "memory");
	return c != 0;
}

static inline int atomic_add_return(int i, atomic_t *v)
{
	return i + xadd(&v->counter, i);
}

static inline int atomic_sub_return(int i, atomic_t *v)
{
	return atomic_add_return(-i, v);
}

#define atomic_inc_return(v)  (atomic_add_return(1, v))
#define atomic_dec_return(v)  (atomic_sub_return(1, v))

#endif /* __CR_ATOMIC_H__ */