atomic-polyfill
This crate polyfills atomics on targets where they're not available, using critical sections. It is intended to be a drop-in replacement for core::sync::atomic.
There are two "levels" of polyfilling:
- Native: No polyfilling is performed, the native
core::sync::atomic::AtomicXXis reexported. - Full: Both load/store and compare-and-set operations are polyfilled.
Target support
The right polyfill level is automatically picked based on the target and the atomic width:
| Target | Level | Level for u64/i64 |
|---|---|---|
| thumbv4t | Full | Full |
| thumbv6m | Full | Full |
| thumbv7*, thumbv8* | Native | Full |
| riscv32imc | Full | Full |
| riscv32imac | Native | Full |
| xtensa-*-espidf | Native | Native |
| xtensa-esp32-* | Native | Full |
| xtensa-esp32s2-* | Full | Full |
| xtensa-esp32s3-* | Native | Full |
| xtensa-esp8266-* | Full | Full |
| AVR | Full | Full |
For targets not listed above, atomic-polyfill assumes nothing and reexports core::sync::atomic::*. No polyfilling is done. PRs for polyfilling more targets are welcome :)
Note: polyfill is based on critical sections using the critical-section crate. The default implementation is based on disabling all interrupts, so it's unsound on multi-core targets. It is possible to supply a custom
critical section implementation, check the critical-section docs for details.
License
This work is licensed under either of
- Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)
at your option.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.