Trevor Gross e4d716c848 fmod: Correct the normalization of subnormals
Discussed at [1], there was an off-by-one mistake when converting from
the loop routine to using `leading_zeros` for normalization.

Currently, using `EXP_BITS` has the effect that `ix` after the branch
has its MSB _one bit to the left_ of the implicit bit's position,
whereas a shift by `EXP_BITS + 1` ensures that the MSB is exactly at the
implicit bit's position, matching what is done for normals (where the
implicit bit is set to be explicit). This doesn't seem to have any
effect in our implementation since the failing test cases from [1]
appear to still have correct results.

Since the result of using `EXP_BITS + 1` is more consistent with what is
done for normals, apply this here.

[1]: https://github.com/rust-lang/libm/pull/469#discussion_r2012473920
2025-04-16 15:28:10 -05:00
..
2023-01-17 20:41:24 +01:00
2025-01-25 07:38:15 +00:00
2024-10-28 20:08:07 +00:00
2024-11-14 18:13:10 +00:00

libm

A port of MUSL's libm to Rust.

Goals

The short term goal of this library is to enable math support (e.g. sin, atan2) for the wasm32-unknown-unknown target (cf. rust-lang/compiler-builtins). The longer term goal is to enable math support in the core crate.

Already usable

This crate is on crates.io and can be used today in stable #![no_std] programs.

The API documentation can be found here.

Benchmark

The benchmarks are located in crates/libm-bench and require a nightly Rust toolchain. To run all benchmarks:

cargo +nightly bench --all

Contributing

Please check CONTRIBUTING.md

Minimum Rust version policy

This crate supports rustc 1.63 and newer.

License

Usage is licensed under the MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT).

Contribution

Contributions are licensed under both the MIT license and the Apache License, Version 2.0 (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0). 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 mentioned, without any additional terms or conditions.

See LICENSE.txt for full details.