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37d33038 | 1 | /* POSIX spinlock implementation. ia64 version. |
35457070 | 2 | Copyright (C) 2000, 2003 Free Software Foundation, Inc. |
37d33038 UD |
3 | This file is part of the GNU C Library. |
4 | Contributed by Jes Sorensen <jes@linuxcare.com> | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
cc7375ce RM |
7 | modify it under the terms of the GNU Lesser General Public License as |
8 | published by the Free Software Foundation; either version 2.1 of the | |
37d33038 UD |
9 | License, or (at your option) any later version. |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
cc7375ce | 14 | Lesser General Public License for more details. |
37d33038 | 15 | |
cc7375ce | 16 | You should have received a copy of the GNU Lesser General Public |
37d33038 UD |
17 | License along with the GNU C Library; see the file COPYING.LIB. If not, |
18 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include <errno.h> | |
22 | #include <pthread.h> | |
27ee0a55 | 23 | #include "internals.h" |
35457070 | 24 | #include <ia64intrin.h> |
37d33038 UD |
25 | |
26 | /* This implementation is inspired by the implementation used in the | |
27 | Linux kernel. */ | |
28 | ||
29 | int | |
30 | __pthread_spin_lock (pthread_spinlock_t *lock) | |
31 | { | |
35457070 UD |
32 | int *p = (int *) lock; |
33 | ||
34 | while (__builtin_expect (__sync_val_compare_and_swap_si (p, 0, 1), 0)) | |
35 | { | |
36 | /* Spin without using the atomic instruction. */ | |
37 | do | |
38 | __asm __volatile ("" : : : "memory"); | |
39 | while (*p); | |
40 | } | |
37d33038 UD |
41 | return 0; |
42 | } | |
43 | weak_alias (__pthread_spin_lock, pthread_spin_lock) | |
44 | ||
45 | ||
46 | int | |
47 | __pthread_spin_trylock (pthread_spinlock_t *lock) | |
48 | { | |
35457070 | 49 | return __sync_val_compare_and_swap_si ((int *) lock, 0, 1) == 0 ? 0 : EBUSY; |
37d33038 UD |
50 | } |
51 | weak_alias (__pthread_spin_trylock, pthread_spin_trylock) | |
52 | ||
53 | ||
54 | int | |
55 | __pthread_spin_unlock (pthread_spinlock_t *lock) | |
56 | { | |
57 | return *lock = 0; | |
58 | } | |
59 | weak_alias (__pthread_spin_unlock, pthread_spin_unlock) | |
60 | ||
61 | ||
62 | int | |
63 | __pthread_spin_init (pthread_spinlock_t *lock, int pshared) | |
64 | { | |
65 | /* We can ignore the `pshared' parameter. Since we are busy-waiting | |
66 | all processes which can access the memory location `lock' points | |
67 | to can use the spinlock. */ | |
68 | return *lock = 0; | |
69 | } | |
70 | weak_alias (__pthread_spin_init, pthread_spin_init) | |
71 | ||
72 | ||
73 | int | |
74 | __pthread_spin_destroy (pthread_spinlock_t *lock) | |
75 | { | |
76 | /* Nothing to do. */ | |
77 | return 0; | |
78 | } | |
79 | weak_alias (__pthread_spin_destroy, pthread_spin_destroy) |