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/* Intel ia32 assembly.
* Don't include directly, use asm.h instead.
*
* Most of this code comes straight out of the Linux kernel.
*
* The terms of the GPL v2 apply.
*/
static inline void barrier(void)
{
__asm__ __volatile__("mfence": : :"memory");
}
static __inline__ void cpu_relax(void)
{
__asm__ __volatile("pause");
}
/* please, use these only if you _really_ know what you're doing
* ... and remember iopl(3) first!! (include sys/io.h)
*/
static inline void cli(void) {
asm volatile("cli": : :"memory");
}
static inline void sti(void) {
asm volatile("sti": : :"memory");
}
typedef struct { int counter; } atomic_t;
#ifdef __i386__
#define ATOMIC_INIT(i) { (i) }
/**
* atomic_read - read atomic variable
* @v: pointer of type atomic_t
*
* Atomically reads the value of @v.
*/
#define atomic_read(v) ((v)->counter)
/**
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
#define atomic_set(v,i) (((v)->counter) = (i))
static __inline__ void atomic_add(int i, atomic_t *v)
{
__asm__ __volatile__(
"lock; addl %1,%0"
:"+m" (v->counter)
:"ir" (i));
}
/**
* atomic_add_return - add and return
* @v: pointer of type atomic_t
* @i: integer value to add
*
* Atomically adds @i to @v and returns @i + @v
*/
static __inline__ int atomic_add_return(int i, atomic_t *v)
{
int __i;
__i = i;
__asm__ __volatile__(
"lock; xaddl %0, %1"
:"+r" (i), "+m" (v->counter)
: : "memory");
return i + __i;
}
#define atomic_inc_return(v) (atomic_add_return(1,v))
#elif defined(__x86_64__)
/* almost the same as i386, but extra care must be taken when
* specifying clobbered registers
*/
#define ATOMIC_INIT(i) { (i) }
/**
* atomic_read - read atomic variable
* @v: pointer of type atomic_t
*
* Atomically reads the value of @v.
*/
static inline int atomic_read(const atomic_t *v)
{
return v->counter;
}
/**
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
static inline void atomic_set(atomic_t *v, int i)
{
v->counter = i;
}
/**
* atomic_add - add integer to atomic variable
* @i: integer value to add
* @v: pointer of type atomic_t
*
* Atomically adds @i to @v.
*/
static inline void atomic_add(int i, atomic_t *v)
{
asm volatile("lock; addl %1,%0"
: "=m" (v->counter)
: "ir" (i), "m" (v->counter));
}
/**
* atomic_add_return - add and return
* @i: integer value to add
* @v: pointer of type atomic_t
*
* Atomically adds @i to @v and returns @i + @v
*/
static inline int atomic_add_return(int i, atomic_t *v)
{
int __i = i;
asm volatile("lock; xaddl %0, %1"
: "+r" (i), "+m" (v->counter)
: : "memory");
return i + __i;
}
#define atomic_inc_return(v) (atomic_add_return(1, v))
#endif
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