1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
//! Implementation of an atomic u64 cell. On 64 bit platforms, this is a
//! re-export of `AtomicU64`. On 32 bit platforms, this is implemented using a
//! `Mutex`.
// `AtomicU64` can only be used on targets with `target_has_atomic` is 64 or greater.
// Once `cfg_target_has_atomic` feature is stable, we can replace it with
// `#[cfg(target_has_atomic = "64")]`.
// Refs: https://github.com/rust-lang/rust/tree/master/src/librustc_target
cfg_has_atomic_u64! {
pub(crate) use std::sync::atomic::AtomicU64;
}
cfg_not_has_atomic_u64! {
use crate::loom::sync::Mutex;
use std::sync::atomic::Ordering;
#[derive(Debug)]
pub(crate) struct AtomicU64 {
inner: Mutex<u64>,
}
impl AtomicU64 {
pub(crate) fn new(val: u64) -> Self {
Self {
inner: Mutex::new(val),
}
}
pub(crate) fn load(&self, _: Ordering) -> u64 {
*self.inner.lock()
}
pub(crate) fn store(&self, val: u64, _: Ordering) {
*self.inner.lock() = val;
}
pub(crate) fn fetch_or(&self, val: u64, _: Ordering) -> u64 {
let mut lock = self.inner.lock();
let prev = *lock;
*lock = prev | val;
prev
}
pub(crate) fn compare_exchange(
&self,
current: u64,
new: u64,
_success: Ordering,
_failure: Ordering,
) -> Result<u64, u64> {
let mut lock = self.inner.lock();
if *lock == current {
*lock = new;
Ok(current)
} else {
Err(*lock)
}
}
pub(crate) fn compare_exchange_weak(
&self,
current: u64,
new: u64,
success: Ordering,
failure: Ordering,
) -> Result<u64, u64> {
self.compare_exchange(current, new, success, failure)
}
}
}
|
