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 xf86atomic.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 1//HAVE_LIBDRM_ATOMIC_PRIMITIVES
42
43 #define HAS_ATOMIC_OPS 1
44
45 typedef 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_inc_return(x) (__sync_add_and_fetch (&(x)->atomic, 1))
53 # define atomic_dec_and_test(x) (__sync_add_and_fetch (&(x)->atomic, -1) == 0)
54 # define atomic_add(x, v) ((void) __sync_add_and_fetch(&(x)->atomic, (v)))
55 # define atomic_dec(x, v) ((void) __sync_sub_and_fetch(&(x)->atomic, (v)))
56 # define atomic_cmpxchg(x, oldv, newv) __sync_val_compare_and_swap (&(x)->atomic, oldv, newv)
57
58 #endif
59
atomic_add_unless(atomic_t * v,int add,int unless)60 static inline int atomic_add_unless(atomic_t *v, int add, int unless)
61 {
62 int c, old;
63 c = atomic_read(v);
64 while (c != unless && (old = atomic_cmpxchg(v, c, c + add)) != c)
65 c = old;
66 return c == unless;
67 }
68
69 #endif
70