Remove unused jhash.h file
[urcu.git] / urcu / compiler.h
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1#ifndef _URCU_COMPILER_H
2#define _URCU_COMPILER_H
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3
4/*
5 * compiler.h
6 *
7 * Compiler definitions.
8 *
6982d6d7 9 * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
af02d47e 10 *
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11 * Permission is hereby granted, free of charge, to any person obtaining a copy
12 * of this software and associated documentation files (the "Software"), to deal
13 * in the Software without restriction, including without limitation the rights
14 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
15 * copies of the Software, and to permit persons to whom the Software is
16 * furnished to do so, subject to the following conditions:
af02d47e 17 *
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18 * The above copyright notice and this permission notice shall be included in
19 * all copies or substantial portions of the Software.
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20 */
21
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22#include <stddef.h> /* for offsetof */
23
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24#define caa_likely(x) __builtin_expect(!!(x), 1)
25#define caa_unlikely(x) __builtin_expect(!!(x), 0)
2dc5fa0f 26
5481ddb3 27#define cmm_barrier() asm volatile("" : : : "memory")
2dc5fa0f 28
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29/*
30 * Instruct the compiler to perform only a single access to a variable
31 * (prohibits merging and refetching). The compiler is also forbidden to reorder
6cf3827c 32 * successive instances of CMM_ACCESS_ONCE(), but only when the compiler is aware of
af02d47e 33 * particular ordering. Compiler ordering can be ensured, for example, by
6cf3827c 34 * putting two CMM_ACCESS_ONCE() in separate C statements.
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35 *
36 * This macro does absolutely -nothing- to prevent the CPU from reordering,
37 * merging, or refetching absolutely anything at any time. Its main intended
38 * use is to mediate communication between process-level code and irq/NMI
39 * handlers, all running on the same CPU.
40 */
6cf3827c 41#define CMM_ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
af02d47e 42
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43#ifndef caa_max
44#define caa_max(a,b) ((a)>(b)?(a):(b))
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45#endif
46
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47#ifndef caa_min
48#define caa_min(a,b) ((a)<(b)?(a):(b))
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49#endif
50
1b27a772 51#if defined(__SIZEOF_LONG__)
06f22bdb 52#define CAA_BITS_PER_LONG (__SIZEOF_LONG__ * 8)
1b27a772 53#elif defined(_LP64)
06f22bdb 54#define CAA_BITS_PER_LONG 64
1b27a772 55#else
06f22bdb 56#define CAA_BITS_PER_LONG 32
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57#endif
58
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59/*
60 * caa_container_of - Get the address of an object containing a field.
61 *
62 * @ptr: pointer to the field.
63 * @type: type of the object.
64 * @member: name of the field within the object.
65 */
66#define caa_container_of(ptr, type, member) \
453629a9 67 ({ \
b194c06e 68 const typeof(((type *) NULL)->member) * __ptr = (ptr); \
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69 (type *)((char *)__ptr - offsetof(type, member)); \
70 })
71
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72#define CAA_BUILD_BUG_ON_ZERO(cond) (sizeof(struct { int:-!!(cond); }))
73#define CAA_BUILD_BUG_ON(cond) ((void)BUILD_BUG_ON_ZERO(cond))
74
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75/*
76 * __rcu is an annotation that documents RCU pointer accesses that need
77 * to be protected by a read-side critical section. Eventually, a static
78 * checker will be able to use this annotation to detect incorrect RCU
79 * usage.
80 */
81#define __rcu
82
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83#ifdef __cplusplus
84#define URCU_FORCE_CAST(type, arg) (reinterpret_cast<type>(arg))
85#else
86#define URCU_FORCE_CAST(type, arg) ((type) (arg))
87#endif
88
ec4e58a3 89#endif /* _URCU_COMPILER_H */
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