# atomic-polyfill
[](https://docs.rs/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::AtomicXX` is reexported.
- Full: Both load/store and compare-and-set operations are polyfilled.
Polyfilling requires a [`critical-section`](https://github.com/rust-embedded/critical-section) implementation for the current target. Check the `critical-section` README for details.
## Target support
The right polyfill level is automatically picked based on the target and the atomic width:
| 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 :)
## License
This work is licensed under either of
- Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
http://www.apache.org/licenses/LICENSE-2.0)
- MIT license ([LICENSE-MIT](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.