1 /* Machine-specific definition for spin locks. x86 version.
2 Copyright (C) 1994-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
19 #ifndef _MACHINE_LOCK_H
20 #define _MACHINE_LOCK_H
22 /* The type of a spin lock variable. */
24 typedef volatile int __spin_lock_t
;
26 /* Value to initialize `__spin_lock_t' variables to. */
28 #define __SPIN_LOCK_INITIALIZER 0
31 #ifndef _EXTERN_INLINE
32 #define _EXTERN_INLINE __extern_inline
37 extern void __spin_unlock (__spin_lock_t
*__lock
);
39 #if defined __USE_EXTERN_INLINES && defined _LIBC
41 __spin_unlock (__spin_lock_t
*__lock
)
43 register int __unlocked
;
44 __asm__
__volatile ("xchgl %0, %1"
45 : "=&r" (__unlocked
), "=m" (*__lock
) : "0" (0)
50 /* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
52 extern int __spin_try_lock (__spin_lock_t
*__lock
);
54 #if defined __USE_EXTERN_INLINES && defined _LIBC
56 __spin_try_lock (__spin_lock_t
*__lock
)
58 register int __locked
;
59 __asm__
__volatile ("xchgl %0, %1"
60 : "=&r" (__locked
), "=m" (*__lock
) : "0" (1)
66 /* Return nonzero if LOCK is locked. */
68 extern int __spin_lock_locked (__spin_lock_t
*__lock
);
70 #if defined __USE_EXTERN_INLINES && defined _LIBC
72 __spin_lock_locked (__spin_lock_t
*__lock
)
79 #endif /* machine-lock.h */