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/* Machine-specific definition for spin locks. i386 version.
Copyright (C) 1994-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _MACHINE_LOCK_H
#define _MACHINE_LOCK_H
/* The type of a spin lock variable. */
typedef volatile int __spin_lock_t;
/* Value to initialize `__spin_lock_t' variables to. */
#define __SPIN_LOCK_INITIALIZER 0
#ifndef _EXTERN_INLINE
#define _EXTERN_INLINE __extern_inline
#endif
/* Unlock LOCK. */
extern void __spin_unlock (__spin_lock_t *__lock);
#if defined __USE_EXTERN_INLINES && defined _LIBC
_EXTERN_INLINE void
__spin_unlock (__spin_lock_t *__lock)
{
register int __unlocked;
__asm__ __volatile ("xchgl %0, %1"
: "=&r" (__unlocked), "=m" (*__lock) : "0" (0)
: "memory");
}
#endif
/* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
extern int __spin_try_lock (__spin_lock_t *__lock);
#if defined __USE_EXTERN_INLINES && defined _LIBC
_EXTERN_INLINE int
__spin_try_lock (__spin_lock_t *__lock)
{
register int __locked;
__asm__ __volatile ("xchgl %0, %1"
: "=&r" (__locked), "=m" (*__lock) : "0" (1)
: "memory");
return !__locked;
}
#endif
/* Return nonzero if LOCK is locked. */
extern int __spin_lock_locked (__spin_lock_t *__lock);
#if defined __USE_EXTERN_INLINES && defined _LIBC
_EXTERN_INLINE int
__spin_lock_locked (__spin_lock_t *__lock)
{
return *__lock != 0;
}
#endif
#endif /* machine-lock.h */
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