mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-11 03:52:59 +00:00
58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
// locks.h - Thread synchronization primitives. AArch64 implementation.
|
|
|
|
#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 __sync_bool_compare_and_swap(addr, old, new_val);
|
|
}
|
|
|
|
// 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)
|
|
{
|
|
__sync_synchronize();
|
|
*addr = new_val;
|
|
}
|
|
|
|
// Compare_and_swap with release semantics instead of acquire semantics.
|
|
// On many architecture, the operation makes both guarantees, so the
|
|
// implementation can be the same.
|
|
inline static bool
|
|
compare_and_swap_release(volatile obj_addr_t *addr,
|
|
obj_addr_t old,
|
|
obj_addr_t new_val)
|
|
{
|
|
return __sync_bool_compare_and_swap(addr, old, new_val);
|
|
}
|
|
|
|
// Ensure that subsequent instructions do not execute on stale
|
|
// data that was loaded from memory before the barrier.
|
|
inline static void
|
|
read_barrier()
|
|
{
|
|
__sync_synchronize();
|
|
}
|
|
|
|
// Ensure that prior stores to memory are completed with respect to other
|
|
// processors.
|
|
inline static void
|
|
write_barrier()
|
|
{
|
|
__sync_synchronize();
|
|
}
|
|
#endif
|