| /* Machine-specific definition for spin locks. i386 version. |
| Copyright (C) 1994-2014 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_INLINE void |
| __spin_unlock (__spin_lock_t *__lock) |
| { |
| register int __unlocked; |
| __asm__ __volatile ("xchgl %0, %1" |
| : "=&r" (__unlocked), "=m" (*__lock) : "0" (0) |
| : "memory"); |
| } |
| |
| /* 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) |
| : "memory"); |
| 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 */ |