local.h

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#ifndef _ALPHA_LOCAL_H
#define _ALPHA_LOCAL_H

#include <linux/percpu.h>
#include <linux/atomic.h>

typedef struct
{
    atomic_long_t a;
} local_t;

#define LOCAL_INIT(i)   { ATOMIC_LONG_INIT(i) }
#define local_read(l)   atomic_long_read(&(l)->a)
#define local_set(l,i)  atomic_long_set(&(l)->a, (i))
#define local_inc(l)    atomic_long_inc(&(l)->a)
#define local_dec(l)    atomic_long_dec(&(l)->a)
#define local_add(i,l)  atomic_long_add((i),(&(l)->a))
#define local_sub(i,l)  atomic_long_sub((i),(&(l)->a))

static __inline__ long local_add_return(long i, local_t * l)
{
    long temp, result;
    __asm__ __volatile__(
    "1: ldq_l %0,%1\n"
    "   addq %0,%3,%2\n"
    "   addq %0,%3,%0\n"
    "   stq_c %0,%1\n"
    "   beq %0,2f\n"
    ".subsection 2\n"
    "2: br 1b\n"
    ".previous"
    :"=&r" (temp), "=m" (l->a.counter), "=&r" (result)
    :"Ir" (i), "m" (l->a.counter) : "memory");
    return result;
}

static __inline__ long local_sub_return(long i, local_t * l)
{
    long temp, result;
    __asm__ __volatile__(
    "1: ldq_l %0,%1\n"
    "   subq %0,%3,%2\n"
    "   subq %0,%3,%0\n"
    "   stq_c %0,%1\n"
    "   beq %0,2f\n"
    ".subsection 2\n"
    "2: br 1b\n"
    ".previous"
    :"=&r" (temp), "=m" (l->a.counter), "=&r" (result)
    :"Ir" (i), "m" (l->a.counter) : "memory");
    return result;
}

#define local_cmpxchg(l, o, n) \
    (cmpxchg_local(&((l)->a.counter), (o), (n)))
#define local_xchg(l, n) (xchg_local(&((l)->a.counter), (n)))

#define local_add_unless(l, a, u)               \
({                              \
    long c, old;                        \
    c = local_read(l);                  \
    for (;;) {                      \
        if (unlikely(c == (u)))             \
            break;                  \
        old = local_cmpxchg((l), c, c + (a));   \
        if (likely(old == c))               \
            break;                  \
        c = old;                    \
    }                           \
    c != (u);                       \
})
#define local_inc_not_zero(l) local_add_unless((l), 1, 0)

#define local_add_negative(a, l) (local_add_return((a), (l)) < 0)

#define local_dec_return(l) local_sub_return(1,(l))

#define local_inc_return(l) local_add_return(1,(l))

#define local_sub_and_test(i,l) (local_sub_return((i), (l)) == 0)

#define local_inc_and_test(l) (local_add_return(1, (l)) == 0)

#define local_dec_and_test(l) (local_sub_return(1, (l)) == 0)

/* Verify if faster than atomic ops */
#define __local_inc(l)      ((l)->a.counter++)
#define __local_dec(l)      ((l)->a.counter++)
#define __local_add(i,l)    ((l)->a.counter+=(i))
#define __local_sub(i,l)    ((l)->a.counter-=(i))

#endif /* _ALPHA_LOCAL_H */