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/* Machine-specific definition for spin locks. Alpha 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 long int __spin_lock_t;
/* Value to initialize `__spin_lock_t' variables to. */
#define __SPIN_LOCK_INITIALIZER 0L
#ifndef _EXTERN_INLINE
#define _EXTERN_INLINE extern __inline
#endif
/* Unlock LOCK. */
_EXTERN_INLINE void
__spin_unlock (__spin_lock_t *__lock)
{
__asm__ __volatile__ ("mb; stq $31, %0; mb"
: "=m" (__lock));
}
/* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
_EXTERN_INLINE int
__spin_try_lock (register __spin_lock_t *__lock)
{
register long int __rtn, __tmp;
do
{
__asm__ __volatile__ ("mb; ldq_l %0,%1" /* Load lock value into TMP. */
: "=r" (__tmp) : "m" (*__lock));
__rtn = 2; /* Load locked value into RTN. */
if (__tmp)
/* The lock is already taken. */
return 0;
/* The lock is not taken; try to get it now. */
__asm__ __volatile__ ("stq_c %0,%1"
: "=r" (__rtn), "=m" (*__lock)
: "0" (__rtn), "1" (*__lock));
/* RTN is clear if stq_c was interrupted; loop to try the lock again. */
} while (! __rtn);
/* RTN is now nonzero; we have the lock. */
return __rtn;
}
/* Return nonzero if LOCK is locked. */
_EXTERN_INLINE int
__spin_lock_locked (__spin_lock_t *__lock)
{
return *__lock != 0;
}
#endif /* machine-lock.h */
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