xf86atomic.h revision bf6cc7dc 
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#if HAVE_LIBDRM_ATOMIC_PRIMITIVES
38
39#define HAS_ATOMIC_OPS 1
40
41typedef struct {
42	int atomic;
43} atomic_t;
44
45# define atomic_read(x) ((x)->atomic)
46# define atomic_set(x, val) ((x)->atomic = (val))
47# define atomic_inc(x) ((void) __sync_fetch_and_add (&(x)->atomic, 1))
48# define atomic_inc_return(x) (__sync_add_and_fetch (&(x)->atomic, 1))
49# define atomic_dec_and_test(x) (__sync_add_and_fetch (&(x)->atomic, -1) == 0)
50# define atomic_add(x, v) ((void) __sync_add_and_fetch(&(x)->atomic, (v)))
51# define atomic_dec(x, v) ((void) __sync_sub_and_fetch(&(x)->atomic, (v)))
52# define atomic_cmpxchg(x, oldv, newv) __sync_val_compare_and_swap (&(x)->atomic, oldv, newv)
53
54#endif
55
56#if HAVE_LIB_ATOMIC_OPS
57#include <atomic_ops.h>
58
59#define HAS_ATOMIC_OPS 1
60
61typedef struct {
62	AO_t atomic;
63} atomic_t;
64
65# define atomic_read(x) AO_load_full(&(x)->atomic)
66# define atomic_set(x, val) AO_store_full(&(x)->atomic, (val))
67# define atomic_inc(x) ((void) AO_fetch_and_add1_full(&(x)->atomic))
68# define atomic_inc_return(x) (AO_fetch_and_add1_full(&(x)->atomic) + 1)
69# define atomic_add(x, v) ((void) AO_fetch_and_add_full(&(x)->atomic, (v)))
70# define atomic_dec(x, v) ((void) AO_fetch_and_add_full(&(x)->atomic, -(v)))
71# define atomic_dec_and_test(x) (AO_fetch_and_sub1_full(&(x)->atomic) == 1)
72# define atomic_cmpxchg(x, oldv, newv) AO_compare_and_swap_full(&(x)->atomic, oldv, newv)
73
74#endif
75
76#if (defined(__sun) || defined(__NetBSD__)) && !defined(HAS_ATOMIC_OPS)  /* Solaris & OpenSolaris & NetBSD */
77
78#include <sys/atomic.h>
79#define HAS_ATOMIC_OPS 1
80
81#if defined(__NetBSD__)
82#define LIBDRM_ATOMIC_TYPE unsigned int
83#else
84#define LIBDRM_ATOMIC_TYPE uint_t
85#endif
86
87typedef struct { volatile LIBDRM_ATOMIC_TYPE atomic; } atomic_t;
88
89# define atomic_read(x) (int) ((x)->atomic)
90# define atomic_set(x, val) ((x)->atomic = (LIBDRM_ATOMIC_TYPE)(val))
91# define atomic_inc(x) (atomic_inc_uint (&(x)->atomic))
92# define atomic_inc_return(x) (atomic_inc_uint_nv(&(x)->atomic))
93# define atomic_dec_and_test(x) (atomic_dec_uint_nv(&(x)->atomic) == 0)
94# define atomic_add(x, v) (atomic_add_int(&(x)->atomic, (v)))
95# define atomic_dec(x, v) (atomic_add_int(&(x)->atomic, -(v)))
96# define atomic_cmpxchg(x, oldv, newv) atomic_cas_uint (&(x)->atomic, oldv, newv)
97
98#endif
99
100#if !defined(HAS_ATOMIC_OPS)
101#error libdrm requires atomic operations, please define them for your CPU/compiler.
102#endif
103
104static inline int atomic_add_unless(atomic_t *v, int add, int unless)
105{
106	int c, old;
107	c = atomic_read(v);
108	while (c != unless && (old = atomic_cmpxchg(v, c, c + add)) != c)
109		c = old;
110	return c == unless;
111}
112
113#endif
114