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#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;

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

#define atomic_read(v)          ((v)->counter)

#define atomic_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 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));

}

/*

 * 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;

}

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;

}

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

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

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

#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)

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

#define atomic_dec(v) atomic_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 */