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