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/* |
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* m68k spinlock operations |
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* |
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* No SMP with m68k, so these functions only implement simple locks that |
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* always depress with sched_yield(). |
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* |
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* $Id: spinlock.h.in,v 1.1 2007/05/24 12:54:09 mbuna Exp $ |
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*/ |
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#ifndef INCLUDED_PEAK_SPINLOCK_H_ |
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#define INCLUDED_PEAK_SPINLOCK_H_ |
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|
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#ifdef HAVE_CONFIG_H |
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#include "config.h" |
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#endif |
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#include <pthread.h> |
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#include <unistd.h> |
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#ifdef HAVE_SCHED_H |
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#include <sched.h> |
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#endif |
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|
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#if defined(__cplusplus) |
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extern "C" { |
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#endif |
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|
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/* PEAK INTERNAL SPIN LOCK |
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* |
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* _peak_spinlock_lock(lockp) |
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* _peak_spinlock_lock_try(lockp) - returns 0 (busy) or 1 (got the lock) |
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* _peak_spinlock_unlock(lockp) |
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* |
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*/ |
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|
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extern int _peak_is_threaded; |
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|
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typedef volatile unsigned char peak_spinlock_t; |
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#define PEAK_SPINLOCK_INITIALIZER (0) |
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|
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/* set *spinlock to 1 and returns previous value */ |
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static inline unsigned |
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__peak_spinlock_testandset(register peak_spinlock_t *lockp) |
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{ |
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int ret; |
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|
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__asm__ __volatile__("tas %1; " |
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"seq %0" |
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: "=dm" (ret), "=m" (*lockp) |
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: "1" (*lockp)); |
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return ret & 1; |
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} |
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|
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static inline void |
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_peak_spinlock_lock(peak_spinlock_t *lockp) |
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{ |
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if (!_peak_is_threaded) /* set only if peak uses several threads */ |
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return; |
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|
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while (__peak_spinlock_testandset(lockp)) |
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sched_yield(); |
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} |
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|
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static inline int |
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_peak_spinlock_lock_try(peak_spinlock_t *lockp) |
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{ |
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if (!_peak_is_threaded) |
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return 1; /* always succeed */ |
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|
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return !__peak_spinlock_testandset(lockp); |
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} |
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|
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static inline void |
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_peak_spinlock_unlock(peak_spinlock_t *lockp) |
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{ |
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if (!_peak_is_threaded) |
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return; |
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|
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*lockp = 0; |
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} |
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|
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#if defined(__cplusplus) |
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} |
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#endif |
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|
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#endif /* INCLUDED_PEAK_SPINLOCK_H_ */ |
