mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-17 18:40:14 +00:00
67 lines
1.8 KiB
C
67 lines
1.8 KiB
C
/* Machine-specific definition for spin locks. i386 version.
|
|
Copyright (C) 1994 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 Library General Public License as
|
|
published by the Free Software Foundation; either version 2 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
|
|
Cambridge, MA 02139, USA. */
|
|
|
|
#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_INLINE void
|
|
__spin_unlock (__spin_lock_t *__lock)
|
|
{
|
|
register int __unlocked;
|
|
__asm__ __volatile ("xchgl %0, %1"
|
|
: "=&r" (__unlocked), "=m" (*__lock) : "0" (0));
|
|
}
|
|
|
|
/* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
|
|
|
|
_EXTERN_INLINE int
|
|
__spin_try_lock (__spin_lock_t *__lock)
|
|
{
|
|
register int __locked;
|
|
__asm__ __volatile ("xchgl %0, %1"
|
|
: "=&r" (__locked), "=m" (*__lock) : "0" (1));
|
|
return !__locked;
|
|
}
|
|
|
|
/* Return nonzero if LOCK is locked. */
|
|
|
|
_EXTERN_INLINE int
|
|
__spin_lock_locked (__spin_lock_t *__lock)
|
|
{
|
|
return *__lock != 0;
|
|
}
|
|
|
|
|
|
#endif /* machine-lock.h */
|