xf86atomic.h revision a884aba1 
1/*
2 * Copyright © 2009 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 *
23 * Authors:
24 *    Chris Wilson <chris@chris-wilson.co.uk>
25 *
26 */
27
28/**
29 * @file xf86atomics.h
30 *
31 * Private definitions for atomic operations
32 */
33
34#ifndef LIBDRM_ATOMICS_H
35#define LIBDRM_ATOMICS_H
36
37#ifdef HAVE_CONFIG_H
38#include "config.h"
39#endif
40
41#if HAVE_LIBDRM_ATOMIC_PRIMITIVES
42
43#define HAS_ATOMIC_OPS 1
44
45typedef struct {
46	int atomic;
47} atomic_t;
48
49# define atomic_read(x) ((x)->atomic)
50# define atomic_set(x, val) ((x)->atomic = (val))
51# define atomic_inc(x) ((void) __sync_fetch_and_add (&(x)->atomic, 1))
52# define atomic_dec_and_test(x) (__sync_fetch_and_add (&(x)->atomic, -1) == 1)
53# define atomic_add(x, v) ((void) __sync_add_and_fetch(&(x)->atomic, (v)))
54# define atomic_dec(x, v) ((void) __sync_sub_and_fetch(&(x)->atomic, (v)))
55# define atomic_cmpxchg(x, oldv, newv) __sync_val_compare_and_swap (&(x)->atomic, oldv, newv)
56
57#endif
58
59#if HAVE_LIB_ATOMIC_OPS
60#include <atomic_ops.h>
61
62#define HAS_ATOMIC_OPS 1
63
64typedef struct {
65	AO_t atomic;
66} atomic_t;
67
68# define atomic_read(x) AO_load_full(&(x)->atomic)
69# define atomic_set(x, val) AO_store_full(&(x)->atomic, (val))
70# define atomic_inc(x) ((void) AO_fetch_and_add1_full(&(x)->atomic))
71# define atomic_add(x, v) ((void) AO_fetch_and_add_full(&(x)->atomic, (v)))
72# define atomic_dec(x, v) ((void) AO_fetch_and_add_full(&(x)->atomic, -(v)))
73# define atomic_dec_and_test(x) (AO_fetch_and_sub1_full(&(x)->atomic) == 1)
74# define atomic_cmpxchg(x, oldv, newv) AO_compare_and_swap_full(&(x)->atomic, oldv, newv)
75
76#endif
77
78#if defined(__sun) && !defined(HAS_ATOMIC_OPS)  /* Solaris & OpenSolaris */
79
80#include <sys/atomic.h>
81#define HAS_ATOMIC_OPS 1
82
83typedef struct { uint_t atomic; } atomic_t;
84
85# define atomic_read(x) (int) ((x)->atomic)
86# define atomic_set(x, val) ((x)->atomic = (uint_t)(val))
87# define atomic_inc(x) (atomic_inc_uint (&(x)->atomic))
88# define atomic_dec_and_test(x) (atomic_dec_uint_nv(&(x)->atomic) == 0)
89# define atomic_add(x, v) (atomic_add_int(&(x)->atomic, (v)))
90# define atomic_dec(x, v) (atomic_add_int(&(x)->atomic, -(v)))
91# define atomic_cmpxchg(x, oldv, newv) atomic_cas_uint (&(x)->atomic, oldv, newv)
92
93#endif
94
95#if defined(__NetBSD__) && !defined(HAS_ATOMIC_OPS)  /* NetBSD */
96
97#include <sys/atomic.h>
98#define HAS_ATOMIC_OPS 1
99
100typedef struct { int atomic; } atomic_t;
101
102# define atomic_read(x) (int) ((x)->atomic)
103# define atomic_set(x, val) ((x)->atomic = (val))
104# define atomic_inc(x) (atomic_inc_uint (&(x)->atomic))
105# define atomic_dec_and_test(x) (atomic_dec_uint_nv(&(x)->atomic) == 0)
106# define atomic_add(x, v) (atomic_add_int(&(x)->atomic, (v)))
107# define atomic_dec(x, v) (atomic_add_int(&(x)->atomic, -(v)))
108# define atomic_cmpxchg(x, oldv, newv) atomic_cas_uint (&(x)->atomic, oldv, newv)
109
110#endif
111
112#if ! HAS_ATOMIC_OPS
113#error libdrm requires atomic operations, please define them for your CPU/compiler.
114#endif
115
116static inline int atomic_add_unless(atomic_t *v, int add, int unless)
117{
118	int c, old;
119	c = atomic_read(v);
120	while (c != unless && (old = atomic_cmpxchg(v, c, c + add)) != c)
121		c = old;
122	return c == unless;
123}
124
125#endif
126