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74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
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/* Machine-specific definition for spin locks. MIPS version.
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Copyright (C) 1994 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#ifndef _MACHINE_LOCK_H
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#define _MACHINE_LOCK_H
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/* The type of a spin lock variable. */
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typedef __volatile int __spin_lock_t;
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/* Value to initialize `__spin_lock_t' variables to. */
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#define __SPIN_LOCK_INITIALIZER 0
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#ifndef _EXTERN_INLINE
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#define _EXTERN_INLINE extern __inline
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#endif
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/* Unlock LOCK. */
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_EXTERN_INLINE void
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__spin_unlock (__spin_lock_t *__lock)
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{
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*__lock = 0;
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}
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/* Try to lock LOCK; return nonzero if we locked it, zero if another has. */
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_EXTERN_INLINE int
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__spin_try_lock (register __spin_lock_t *__lock)
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{
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register int __rtn;
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__asm__ __volatile (".set noreorder");
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#if 0
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__asm__ __volatile ("lw %0,0(%1)": "=r" (__rtn) : "r" (__lock));
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__asm__ __volatile ("sw %0,0(%0)": : "r" (__lock));
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__asm__ __volatile ("xor %0,%1,%0": "=r" (__rtn) : "r" (__lock));
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#else
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/* Use the Mach microkernel's emulated TAS pseudo-instruction. */
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register int __rtn __asm__ ("a0");
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__asm__ __volatile (".word 0xf ! %0 " : "=r" (__rtn) : "0" (__lock));
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#endif
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__asm__ __volatile (".set reorder");
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return __rtn ^ (int) __lock;
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}
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/* Return nonzero if LOCK is locked. */
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_EXTERN_INLINE int
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__spin_lock_locked (__spin_lock_t *__lock)
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{
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return *__lock != 0;
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}
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#endif /* machine-lock.h */
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