#ifndef _ALPHA_ATOMIC_H
#define _ALPHA_ATOMIC_H

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc...
 *
 * But use these as seldom as possible since they are much slower
 * than regular operations.
 */


/*
 * Counter is volatile to make sure gcc doesn't try to be clever
 * and move things around on us. We need to use _exactly_ the address
 * the user gave us, not some alias that contains the same information.
 */
typedef struct { volatile int counter; } atomic_t;
typedef struct { volatile long counter; } atomic64_t;

#define ATOMIC_INIT(i)          ( (atomic_t) { (i) } )
#define ATOMIC64_INIT(i)        ( (atomic64_t) { (i) } )

#define atomic_read(v)          ((v)->counter + 0)
#define atomic64_read(v)        ((v)->counter + 0)

#define atomic_set(v,i)         ((v)->counter = (i))
#define atomic64_set(v,i)       ((v)->counter = (i))

/*
 * To get proper branch prediction for the main line, we must branch
 * forward to code at the end of this object's .text section, then
 * branch back to restart the operation.
 */

static __inline__ void atomic_add(int i, atomic_t * v)
{
        unsigned long temp;
        __asm__ __volatile__(
        "1:     ldl_l %0,%1\n"
        "       addl %0,%2,%0\n"
        "       stl_c %0,%1\n"
        "       beq %0,2f\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter)
        :"Ir" (i), "m" (v->counter));
}

static __inline__ void atomic64_add(long i, atomic64_t * v)
{
        unsigned long temp;
        __asm__ __volatile__(
        "1:     ldq_l %0,%1\n"
        "       addq %0,%2,%0\n"
        "       stq_c %0,%1\n"
        "       beq %0,2f\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter)
        :"Ir" (i), "m" (v->counter));
}

static __inline__ void atomic_sub(int i, atomic_t * v)
{
        unsigned long temp;
        __asm__ __volatile__(
        "1:     ldl_l %0,%1\n"
        "       subl %0,%2,%0\n"
        "       stl_c %0,%1\n"
        "       beq %0,2f\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter)
        :"Ir" (i), "m" (v->counter));
}

static __inline__ void atomic64_sub(long i, atomic64_t * v)
{
        unsigned long temp;
        __asm__ __volatile__(
        "1:     ldq_l %0,%1\n"
        "       subq %0,%2,%0\n"
        "       stq_c %0,%1\n"
        "       beq %0,2f\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter)
        :"Ir" (i), "m" (v->counter));
}


/*
 * Same as above, but return the result value
 */
static __inline__ long atomic_add_return(int i, atomic_t * v)
{
        long temp, result;
        __asm__ __volatile__(
        "1:     ldl_l %0,%1\n"
        "       addl %0,%3,%2\n"
        "       addl %0,%3,%0\n"
        "       stl_c %0,%1\n"
        "       beq %0,2f\n"
        "       mb\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)
        :"Ir" (i), "m" (v->counter) : "memory");
        return result;
}

#define atomic_add_negative(a, v)       (atomic_add_return((a), (v)) < 0)

static __inline__ long atomic64_add_return(long i, atomic64_t * v)
{
        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"
        "       mb\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)
        :"Ir" (i), "m" (v->counter) : "memory");
        return result;
}

static __inline__ long atomic_sub_return(int i, atomic_t * v)
{
        long temp, result;
        __asm__ __volatile__(
        "1:     ldl_l %0,%1\n"
        "       subl %0,%3,%2\n"
        "       subl %0,%3,%0\n"
        "       stl_c %0,%1\n"
        "       beq %0,2f\n"
        "       mb\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)
        :"Ir" (i), "m" (v->counter) : "memory");
        return result;
}

static __inline__ long atomic64_sub_return(long i, atomic64_t * v)
{
        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"
        "       mb\n"
        ".subsection 2\n"
        "2:     br 1b\n"
        ".previous"
        :"=&r" (temp), "=m" (v->counter), "=&r" (result)
        :"Ir" (i), "m" (v->counter) : "memory");
        return result;
}

#define atomic_dec_return(v) atomic_sub_return(1,(v))
#define atomic64_dec_return(v) atomic64_sub_return(1,(v))

#define atomic_inc_return(v) atomic_add_return(1,(v))
#define atomic64_inc_return(v) atomic64_add_return(1,(v))

#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
#define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)

#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
#define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)

#define atomic_inc(v) atomic_add(1,(v))
#define atomic64_inc(v) atomic64_add(1,(v))

#define atomic_dec(v) atomic_sub(1,(v))
#define atomic64_dec(v) atomic64_sub(1,(v))

#define smp_mb__before_atomic_dec()     smp_mb()
#define smp_mb__after_atomic_dec()      smp_mb()
#define smp_mb__before_atomic_inc()     smp_mb()
#define smp_mb__after_atomic_inc()      smp_mb()

#endif /* _ALPHA_ATOMIC_H */