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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 */