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80 lines
2.1 KiB
C
80 lines
2.1 KiB
C
/* Machine-specific definition for spin locks. x86 version.
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Copyright (C) 1994-2023 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#ifndef _MACHINE_LOCK_H
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#define _MACHINE_LOCK_H
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/* The type of a spin lock variable. */
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typedef volatile int __spin_lock_t;
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/* Value to initialize `__spin_lock_t' variables to. */
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#define __SPIN_LOCK_INITIALIZER 0
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#ifndef _EXTERN_INLINE
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#define _EXTERN_INLINE __extern_inline
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#endif
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/* Unlock LOCK. */
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extern void __spin_unlock (__spin_lock_t *__lock);
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#if defined __USE_EXTERN_INLINES && defined _LIBC
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_EXTERN_INLINE void
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__spin_unlock (__spin_lock_t *__lock)
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{
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register int __unlocked;
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__asm__ __volatile ("xchgl %0, %1"
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: "=&r" (__unlocked), "=m" (*__lock) : "0" (0)
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: "memory");
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}
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#endif
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/* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
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extern int __spin_try_lock (__spin_lock_t *__lock);
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#if defined __USE_EXTERN_INLINES && defined _LIBC
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_EXTERN_INLINE int
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__spin_try_lock (__spin_lock_t *__lock)
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{
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register int __locked;
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__asm__ __volatile ("xchgl %0, %1"
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: "=&r" (__locked), "=m" (*__lock) : "0" (1)
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: "memory");
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return !__locked;
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}
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#endif
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/* Return nonzero if LOCK is locked. */
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extern int __spin_lock_locked (__spin_lock_t *__lock);
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#if defined __USE_EXTERN_INLINES && defined _LIBC
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_EXTERN_INLINE int
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__spin_lock_locked (__spin_lock_t *__lock)
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{
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return *__lock != 0;
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}
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#endif
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#endif /* machine-lock.h */
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