/*
   * Generic implementation of 64-bit atomics using spinlocks,
   * useful on processors that don't have 64-bit atomic instructions.
   *
   * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  #ifndef _ASM_GENERIC_ATOMIC64_H
  #define _ASM_GENERIC_ATOMIC64_H
  
  typedef struct {
  	long long counter;
  } atomic64_t;
  
  #define ATOMIC64_INIT(i)	{ (i) }
  
  extern long long atomic64_read(const atomic64_t *v);
  extern void	 atomic64_set(atomic64_t *v, long long i);

  #define atomic64_set_release(v, i)	atomic64_set((v), (i))

  #define ATOMIC64_OP(op)							\
  extern void	 atomic64_##op(long long a, atomic64_t *v);
  
  #define ATOMIC64_OP_RETURN(op)						\
  extern long long atomic64_##op##_return(long long a, atomic64_t *v);

  #define ATOMIC64_FETCH_OP(op)						\
  extern long long atomic64_fetch_##op(long long a, atomic64_t *v);
  
  #define ATOMIC64_OPS(op)	ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op) ATOMIC64_FETCH_OP(op)

  
  ATOMIC64_OPS(add)
  ATOMIC64_OPS(sub)

  #undef ATOMIC64_OPS
  #define ATOMIC64_OPS(op)	ATOMIC64_OP(op) ATOMIC64_FETCH_OP(op)
  
  ATOMIC64_OPS(and)
  ATOMIC64_OPS(or)
  ATOMIC64_OPS(xor)

  #undef ATOMIC64_OPS

  #undef ATOMIC64_FETCH_OP

  #undef ATOMIC64_OP_RETURN
  #undef ATOMIC64_OP

  extern long long atomic64_dec_if_positive(atomic64_t *v);
  extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
  extern long long atomic64_xchg(atomic64_t *v, long long new);
  extern int	 atomic64_add_unless(atomic64_t *v, long long a, long long u);
  
  #define atomic64_add_negative(a, v)	(atomic64_add_return((a), (v)) < 0)
  #define atomic64_inc(v)			atomic64_add(1LL, (v))
  #define atomic64_inc_return(v)		atomic64_add_return(1LL, (v))
  #define atomic64_inc_and_test(v) 	(atomic64_inc_return(v) == 0)
  #define atomic64_sub_and_test(a, v)	(atomic64_sub_return((a), (v)) == 0)
  #define atomic64_dec(v)			atomic64_sub(1LL, (v))
  #define atomic64_dec_return(v)		atomic64_sub_return(1LL, (v))
  #define atomic64_dec_and_test(v)	(atomic64_dec_return((v)) == 0)
  #define atomic64_inc_not_zero(v) 	atomic64_add_unless((v), 1LL, 0LL)
  
  #endif  /*  _ASM_GENERIC_ATOMIC64_H  */