63 lines
2.0 KiB
Rust
63 lines
2.0 KiB
Rust
// -*- mode: rust; -*-
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//
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// This file is part of curve25519-dalek.
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// Copyright (c) 2016-2019 Isis Lovecruft, Henry de Valence
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// See LICENSE for licensing information.
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//
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// Authors:
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// - Isis Agora Lovecruft <isis@patternsinthevoid.net>
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// - Henry de Valence <hdevalence@hdevalence.ca>
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//! Pluggable implementations for different architectures.
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//!
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//! The backend code is split into two parts: a serial backend,
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//! and a vector backend.
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//!
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//! The [`serial`] backend contains 32- and 64-bit implementations of
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//! field arithmetic and scalar arithmetic, as well as implementations
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//! of point operations using the mixed-model strategy (passing
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//! between different curve models depending on the operation).
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//!
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//! The [`vector`] backend contains implementations of vectorized
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//! field arithmetic, used to implement point operations using a novel
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//! implementation strategy derived from parallel formulas of Hisil,
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//! Wong, Carter, and Dawson.
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//!
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//! Because the two strategies give rise to different curve models,
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//! it's not possible to reuse exactly the same scalar multiplication
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//! code (or to write it generically), so both serial and vector
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//! backends contain matching implementations of scalar multiplication
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//! algorithms. These are intended to be selected by a `#[cfg]`-based
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//! type alias.
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//!
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//! The [`vector`] backend is selected by the `simd_backend` cargo
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//! feature; it uses the [`serial`] backend for non-vectorized operations.
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#[cfg(not(any(
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feature = "u32_backend",
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feature = "u64_backend",
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feature = "simd_backend",
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)))]
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compile_error!(
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"no curve25519-dalek backend cargo feature enabled! \
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please enable one of: u32_backend, u64_backend, simd_backend"
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);
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pub mod serial;
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#[cfg(any(
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all(
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feature = "simd_backend",
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any(target_feature = "avx2", target_feature = "avx512ifma")
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),
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all(feature = "nightly", rustdoc)
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))]
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#[cfg_attr(
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feature = "nightly",
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doc(cfg(any(all(
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feature = "simd_backend",
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any(target_feature = "avx2", target_feature = "avx512ifma")
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))))
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)]
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pub mod vector;
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