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// locks.h - Thread synchronization primitives. PowerPC implementation.
/* Copyright (C) 2002,2008 Free Software Foundation
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
#ifndef __SYSDEP_LOCKS_H__
#define __SYSDEP_LOCKS_H__
typedef size_t obj_addr_t; /* Integer type big enough for object */
/* address. */
// Atomically replace *addr by new_val if it was initially equal to old.
// Return true if the comparison succeeded.
// Assumed to have acquire semantics, i.e. later memory operations
// cannot execute before the compare_and_swap finishes.
inline static bool
compare_and_swap (volatile obj_addr_t *addr,
obj_addr_t old,
obj_addr_t new_val)
{
return __atomic_compare_exchange_n (addr, &old, new_val, 0,
__ATOMIC_ACQUIRE, __ATOMIC_RELAXED);
}
// Set *addr to new_val with release semantics, i.e. making sure
// that prior loads and stores complete before this
// assignment.
inline static void
release_set (volatile obj_addr_t *addr, obj_addr_t new_val)
{
__atomic_store_n(addr, new_val, __ATOMIC_RELEASE);
}
// Compare_and_swap with release semantics instead of acquire semantics.
inline static bool
compare_and_swap_release (volatile obj_addr_t *addr, obj_addr_t old,
obj_addr_t new_val)
{
return __atomic_compare_exchange_n (addr, &old, new_val, 0,
__ATOMIC_RELEASE, __ATOMIC_RELAXED);
}
// Ensure that subsequent instructions do not execute on stale
// data that was loaded from memory before the barrier.
inline static void
read_barrier ()
{
__atomic_thread_fence (__ATOMIC_ACQUIRE);
}
// Ensure that prior stores to memory are completed with respect to other
// processors.
inline static void
write_barrier ()
{
__atomic_thread_fence (__ATOMIC_RELEASE);
}
#endif
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