1 // Copyright 2020 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14 #pragma once
15 
16 #include "pw_sync/interrupt_spin_lock.h"
17 #include "pw_sync/yield_core.h"
18 
19 namespace pw::sync {
20 
InterruptSpinLock()21 constexpr InterruptSpinLock::InterruptSpinLock() : native_type_() {}
22 
lock()23 inline void InterruptSpinLock::lock() {
24   while (!try_lock()) {
25     PW_SYNC_YIELD_CORE_FOR_SMT();
26   }
27 }
28 
try_lock()29 inline bool InterruptSpinLock::try_lock() {
30   return !native_type_.test_and_set(std::memory_order_acquire);
31 }
32 
unlock()33 inline void InterruptSpinLock::unlock() {
34   native_type_.clear(std::memory_order_release);
35 }
36 
37 inline InterruptSpinLock::native_handle_type
native_handle()38 InterruptSpinLock::native_handle() {
39   return native_type_;
40 }
41 
42 }  // namespace pw::sync
43