3 * Atomic operations used in the DRM which may or may not be provided by the OS.
5 * \author Eric Anholt <anholt@FreeBSD.org>
9 * Copyright 2004 Eric Anholt
10 * All Rights Reserved.
12 * Permission is hereby granted, free of charge, to any person obtaining a
13 * copy of this software and associated documentation files (the "Software"),
14 * to deal in the Software without restriction, including without limitation
15 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
16 * and/or sell copies of the Software, and to permit persons to whom the
17 * Software is furnished to do so, subject to the following conditions:
19 * The above copyright notice and this permission notice (including the next
20 * paragraph) shall be included in all copies or substantial portions of the
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
24 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
25 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
26 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
27 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
28 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
29 * OTHER DEALINGS IN THE SOFTWARE.
32 /* Many of these implementations are rather fake, but good enough. */
34 typedef u_int32_t atomic_t;
37 #define atomic_set(p, v) (*(p) = (v))
38 #define atomic_read(p) (*(p))
39 #define atomic_inc(p) atomic_add_int(p, 1)
40 #define atomic_dec(p) atomic_subtract_int(p, 1)
41 #define atomic_add(n, p) atomic_add_int(p, n)
42 #define atomic_sub(n, p) atomic_subtract_int(p, n)
43 #else /* __FreeBSD__ */
45 #define atomic_set(p, v) (*(p) = (v))
46 #define atomic_read(p) (*(p))
47 #define atomic_inc(p) (*(p) += 1)
48 #define atomic_dec(p) (*(p) -= 1)
49 #define atomic_add(n, p) (*(p) += (n))
50 #define atomic_sub(n, p) (*(p) -= (n))
52 #define atomic_add_int(p, v) *(p) += v
53 #define atomic_subtract_int(p, v) *(p) -= v
54 #define atomic_set_int(p, bits) *(p) |= (bits)
55 #define atomic_clear_int(p, bits) *(p) &= ~(bits)
56 #endif /* !__FreeBSD__ */
58 #if !defined(__FreeBSD_version) || (__FreeBSD_version < 500000)
60 /* The extra atomic functions from 5.0 haven't been merged to 4.x */
62 atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
73 : "+a" (res) /* 0 (result) */
82 atomic_cmpset_int(__volatile__ int *dst, int old, int new)
93 #endif /* !__i386__ */
94 #endif /* !__FreeBSD_version || __FreeBSD_version < 500000 */
96 static __inline atomic_t
97 test_and_set_bit(int b, volatile void *p)
100 unsigned int m = 1<<b;
101 unsigned int r = *(volatile int *)p & m;
102 *(volatile int *)p |= m;
108 clear_bit(int b, volatile void *p)
110 atomic_clear_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
114 set_bit(int b, volatile void *p)
116 atomic_set_int(((volatile int *)p) + (b >> 5), 1 << (b & 0x1f));
120 test_bit(int b, volatile void *p)
122 return ((volatile int *)p)[b >> 5] & (1 << (b & 0x1f));
126 find_first_zero_bit(volatile void *p, int max)
129 volatile int *ptr = (volatile int *)p;
131 for (b = 0; b < max; b += 32) {
132 if (ptr[b >> 5] != ~0) {
134 if ((ptr[b >> 5] & (1 << (b & 0x1f))) == 0)