LXR linux/include/asm-generic/atomic64.h

   1/*
   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. <paulus@au1.ibm.com>
   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
  14
  15typedef struct {
  16        long long counter;
  17} atomic64_t;
  18
  19#define ATOMIC64_INIT(i)        { (i) }
  20
  21extern long long atomic64_read(const atomic64_t *v);
  22extern void      atomic64_set(atomic64_t *v, long long i);
  23
  24#define ATOMIC64_OP(op)                                                 \
  25extern void      atomic64_##op(long long a, atomic64_t *v);
  26
  27#define ATOMIC64_OP_RETURN(op)                                          \
  28extern long long atomic64_##op##_return(long long a, atomic64_t *v);
  29
  30#define ATOMIC64_OPS(op)        ATOMIC64_OP(op) ATOMIC64_OP_RETURN(op)
  31
  32ATOMIC64_OPS(add)
  33ATOMIC64_OPS(sub)
  34
  35ATOMIC64_OP(and)
  36ATOMIC64_OP(or)
  37ATOMIC64_OP(xor)
  38
  39#undef ATOMIC64_OPS
  40#undef ATOMIC64_OP_RETURN
  41#undef ATOMIC64_OP
  42
  43extern long long atomic64_dec_if_positive(atomic64_t *v);
  44extern long long atomic64_cmpxchg(atomic64_t *v, long long o, long long n);
  45extern long long atomic64_xchg(atomic64_t *v, long long new);
  46extern int       atomic64_add_unless(atomic64_t *v, long long a, long long u);
  47
  48#define atomic64_add_negative(a, v)     (atomic64_add_return((a), (v)) < 0)
  49#define atomic64_inc(v)                 atomic64_add(1LL, (v))
  50#define atomic64_inc_return(v)          atomic64_add_return(1LL, (v))
  51#define atomic64_inc_and_test(v)        (atomic64_inc_return(v) == 0)
  52#define atomic64_sub_and_test(a, v)     (atomic64_sub_return((a), (v)) == 0)
  53#define atomic64_dec(v)                 atomic64_sub(1LL, (v))
  54#define atomic64_dec_return(v)          atomic64_sub_return(1LL, (v))
  55#define atomic64_dec_and_test(v)        (atomic64_dec_return((v)) == 0)
  56#define atomic64_inc_not_zero(v)        atomic64_add_unless((v), 1LL, 0LL)
  57
  58#endif  /*  _ASM_GENERIC_ATOMIC64_H  */
  59