| 1 | /* Machine-specific definition for spin locks. Stub version. |
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| 2 | Copyright (C) 1994-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #ifndef _MACHINE_LOCK_H |
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| 20 | #define _MACHINE_LOCK_H |
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| 21 | |
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| 22 | /* The type of a spin lock variable. */ |
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| 23 | |
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| 24 | typedef volatile int __spin_lock_t; |
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| 25 | |
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| 26 | /* Value to initialize `__spin_lock_t' variables to. */ |
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| 27 | |
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| 28 | #define __SPIN_LOCK_INITIALIZER 0 |
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| 29 | |
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| 30 | |
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| 31 | #ifndef _EXTERN_INLINE |
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| 32 | #define _EXTERN_INLINE __extern_inline |
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| 33 | #endif |
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| 34 | |
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| 35 | /* Unlock LOCK. */ |
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| 36 | |
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| 37 | extern void __spin_unlock (__spin_lock_t *__lock); |
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| 38 | |
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| 39 | #if defined __USE_EXTERN_INLINES && defined _LIBC |
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| 40 | _EXTERN_INLINE void |
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| 41 | __spin_unlock (__spin_lock_t *__lock) |
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| 42 | { |
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| 43 | *__lock = 0; |
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| 44 | } |
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| 45 | #endif |
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| 46 | |
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| 47 | /* Try to lock LOCK; return nonzero if we locked it, zero if another has. */ |
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| 48 | |
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| 49 | extern int __spin_try_lock (__spin_lock_t *__lock); |
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| 50 | |
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| 51 | #if defined __USE_EXTERN_INLINES && defined _LIBC |
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| 52 | _EXTERN_INLINE int |
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| 53 | __spin_try_lock (__spin_lock_t *__lock) |
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| 54 | { |
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| 55 | if (*__lock) |
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| 56 | return 0; |
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| 57 | *__lock = 1; |
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| 58 | return 1; |
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| 59 | } |
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| 60 | #endif |
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| 61 | |
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| 62 | /* Return nonzero if LOCK is locked. */ |
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| 63 | |
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| 64 | extern int __spin_lock_locked (__spin_lock_t *__lock); |
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| 65 | |
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| 66 | #if defined __USE_EXTERN_INLINES && defined _LIBC |
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| 67 | _EXTERN_INLINE int |
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| 68 | __spin_lock_locked (__spin_lock_t *__lock) |
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| 69 | { |
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| 70 | return *__lock != 0; |
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| 71 | } |
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| 72 | #endif |
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| 73 | |
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| 74 | |
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| 75 | #endif /* machine-lock.h */ |
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| 76 | |
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