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Diffstat (limited to 'sysdeps/mach/alpha/machine-lock.h')
-rw-r--r-- | sysdeps/mach/alpha/machine-lock.h | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/sysdeps/mach/alpha/machine-lock.h b/sysdeps/mach/alpha/machine-lock.h new file mode 100644 index 0000000000..42e21d8df2 --- /dev/null +++ b/sysdeps/mach/alpha/machine-lock.h @@ -0,0 +1,80 @@ +/* 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 */ |