1 // locks.h - Thread synchronization primitives. S/390 implementation.
3 /* Copyright (C) 2002 Free Software Foundation
5 This file is part of libgcj.
7 This software is copyrighted work licensed under the terms of the
8 Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
11 #ifndef __SYSDEP_LOCKS_H__
12 #define __SYSDEP_LOCKS_H__
14 typedef size_t obj_addr_t
; /* Integer type big enough for object */
17 // Atomically replace *addr by new_val if it was initially equal to old.
18 // Return true if the comparison succeeded.
19 // Assumed to have acquire semantics, i.e. later memory operations
20 // cannot execute before the compare_and_swap finishes.
22 compare_and_swap(volatile obj_addr_t
*addr
,
23 obj_addr_t old
, obj_addr_t new_val
)
27 __asm__
__volatile__ (
35 : "=&d" (result
), "+d" (old
)
36 : "d" (new_val
), "a" (addr
)
42 // Set *addr to new_val with release semantics, i.e. making sure
43 // that prior loads and stores complete before this
46 release_set(volatile obj_addr_t
*addr
, obj_addr_t new_val
)
48 __asm__
__volatile__("bcr 15,0" : : : "memory");
52 // Compare_and_swap with release semantics instead of acquire semantics.
53 // On many architecture, the operation makes both guarantees, so the
54 // implementation can be the same.
56 compare_and_swap_release(volatile obj_addr_t
*addr
,
57 obj_addr_t old
, obj_addr_t new_val
)
59 return compare_and_swap(addr
, old
, new_val
);
62 // Ensure that subsequent instructions do not execute on stale
63 // data that was loaded from memory before the barrier.
67 __asm__
__volatile__("bcr 15,0" : : : "memory");
70 // Ensure that prior stores to memory are completed with respect to other
75 __asm__
__volatile__("bcr 15,0" : : : "memory");