2 * Generic implementation of 64-bit atomics using spinlocks,
   3 * useful on processors that don't have 64-bit atomic instructions.
   4 *
   5 * Copyright © 2009 Paul Mackerras, IBM Corp. <>
   6 *
   7 * This program is free software; you can redistribute it and/or
   8 * modify it under the terms of the GNU General Public License
   9 * as published by the Free Software Foundation; either version
  10 * 2 of the License, or (at your option) any later version.
  11 */
  12#ifndef _ASM_GENERIC_ATOMIC64_H
  13#define _ASM_GENERIC_ATOMIC64_H
  15typedef struct {
  16        long long counter;
  17} atomic64_t;
  19#define ATOMIC64_INIT(i)        { (i) }
  21extern long long atomic64_read(const atomic64_t *v);
  22extern void      atomic64_set(atomic64_t *v, long long i);
  23extern void      atomic64_add(long long a, atomic64_t *v);
  24extern long long atomic64_add_return(long long a, atomic64_t *v);
  25extern void      atomic64_sub(long long a, atomic64_t *v);
  26extern long long atomic64_sub_return(long long a, atomic64_t *v);
  27extern long long atomic64_dec_if_positive(atomic64_t *v);
  28extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
  29extern long long atomic64_xchg(atomic64_t *v, long long new);
  30extern int       atomic64_add_unless(atomic64_t *v, long long a, long long u);
  32#define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
  33#define atomic64_inc(v)                 atomic64_add(1LL, (v))
  34#define atomic64_inc_return(v)          atomic64_add_return(1LL, (v))
  35#define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
  36#define atomic64_sub_and_test(a, v)     (atomic64_sub_return((a), (v)) == 0)
  37#define atomic64_dec(v)                 atomic64_sub(1LL, (v))
  38#define atomic64_dec_return(v)          atomic64_sub_return(1LL, (v))
  39#define atomic64_dec_and_test(v)        (atomic64_dec_return((v)) == 0)
  40#define atomic64_inc_not_zero(v)        atomic64_add_unless((v), 1LL, 0LL)
  42#endif  /*  _ASM_GENERIC_ATOMIC64_H  */
  43 kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.