diff options
Diffstat (limited to 'libpthread/linuxthreads/spinlock.h')
-rw-r--r-- | libpthread/linuxthreads/spinlock.h | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/libpthread/linuxthreads/spinlock.h b/libpthread/linuxthreads/spinlock.h new file mode 100644 index 000000000..aae18a27b --- /dev/null +++ b/libpthread/linuxthreads/spinlock.h @@ -0,0 +1,102 @@ +/* Linuxthreads - a simple clone()-based implementation of Posix */ +/* threads for Linux. */ +/* Copyright (C) 1998 Xavier Leroy (Xavier.Leroy@inria.fr) */ +/* */ +/* This program 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. */ +/* */ +/* This program 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. */ + +#if defined(TEST_FOR_COMPARE_AND_SWAP) + +extern int __pthread_has_cas; +extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval, + int * spinlock); + +static inline int compare_and_swap(long * ptr, long oldval, long newval, + int * spinlock) +{ + if (__builtin_expect (__pthread_has_cas, 1)) + return __compare_and_swap(ptr, oldval, newval); + else + return __pthread_compare_and_swap(ptr, oldval, newval, spinlock); +} + +#elif defined(HAS_COMPARE_AND_SWAP) + +static inline int compare_and_swap(long * ptr, long oldval, long newval, + int * spinlock) +{ + return __compare_and_swap(ptr, oldval, newval); +} + +#else + +extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval, + int * spinlock); + +static inline int compare_and_swap(long * ptr, long oldval, long newval, + int * spinlock) +{ + return __pthread_compare_and_swap(ptr, oldval, newval, spinlock); +} + +#endif + +/* Internal locks */ + +extern void internal_function __pthread_lock(struct _pthread_fastlock * lock, + pthread_descr self); +extern void internal_function __pthread_unlock(struct _pthread_fastlock *lock); + +static inline void __pthread_init_lock(struct _pthread_fastlock * lock) +{ + lock->__status = 0; + lock->__spinlock = 0; +} + +static inline int __pthread_trylock (struct _pthread_fastlock * lock) +{ + long oldstatus; + + do { + oldstatus = lock->__status; + if (oldstatus != 0) return EBUSY; + } while(! compare_and_swap(&lock->__status, 0, 1, &lock->__spinlock)); + return 0; +} + +#define LOCK_INITIALIZER {0, 0} + +/* Operations on pthread_atomic, which is defined in internals.h */ + +static inline long atomic_increment(struct pthread_atomic *pa) +{ + long oldval; + + do { + oldval = pa->p_count; + } while (!compare_and_swap(&pa->p_count, oldval, oldval + 1, &pa->p_spinlock)); + + return oldval; +} + + +static inline long atomic_decrement(struct pthread_atomic *pa) +{ + long oldval; + + do { + oldval = pa->p_count; + } while (!compare_and_swap(&pa->p_count, oldval, oldval - 1, &pa->p_spinlock)); + + return oldval; +} + +#define ATOMIC_INITIALIZER { 0, 0 } + |