74 lines
1.8 KiB
C
74 lines
1.8 KiB
C
// 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
|