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Diffstat (limited to 'library/portable-simd/README.md')
| -rw-r--r-- | library/portable-simd/README.md | 34 |
1 files changed, 12 insertions, 22 deletions
diff --git a/library/portable-simd/README.md b/library/portable-simd/README.md index db0af2da6..e8ac600de 100644 --- a/library/portable-simd/README.md +++ b/library/portable-simd/README.md @@ -24,19 +24,10 @@ or by setting up `rustup default nightly` or else with `cargo +nightly {build,te ```bash cargo new hellosimd ``` -to create a new crate. Edit `hellosimd/Cargo.toml` to be -```toml -[package] -name = "hellosimd" -version = "0.1.0" -edition = "2018" -[dependencies] -core_simd = { git = "https://github.com/rust-lang/portable-simd" } -``` - -and finally write this in `src/main.rs`: +to create a new crate. Finally write this in `src/main.rs`: ```rust -use core_simd::*; +#![feature(portable_simd)] +use std::simd::f32x4; fn main() { let a = f32x4::splat(10.0); let b = f32x4::from_array([1.0, 2.0, 3.0, 4.0]); @@ -44,24 +35,23 @@ fn main() { } ``` -Explanation: We import all the bindings from the crate with the first line. Then, we construct our SIMD vectors with methods like `splat` or `from_array`. Finally, we can use operators on them like `+` and the appropriate SIMD instructions will be carried out. When we run `cargo run` you should get `[11.0, 12.0, 13.0, 14.0]`. - -## Code Organization +Explanation: We construct our SIMD vectors with methods like `splat` or `from_array`. Next, we can use operators like `+` on them, and the appropriate SIMD instructions will be carried out. When we run `cargo run` you should get `[11.0, 12.0, 13.0, 14.0]`. -Currently the crate is organized so that each element type is a file, and then the 64-bit, 128-bit, 256-bit, and 512-bit vectors using those types are contained in said file. +## Supported vectors -All types are then exported as a single, flat module. +Currently, vectors may have up to 64 elements, but aliases are provided only up to 512-bit vectors. Depending on the size of the primitive type, the number of lanes the vector will have varies. For example, 128-bit vectors have four `f32` lanes and two `f64` lanes. The supported element types are as follows: * **Floating Point:** `f32`, `f64` -* **Signed Integers:** `i8`, `i16`, `i32`, `i64`, `i128`, `isize` -* **Unsigned Integers:** `u8`, `u16`, `u32`, `u64`, `u128`, `usize` -* **Masks:** `mask8`, `mask16`, `mask32`, `mask64`, `mask128`, `masksize` +* **Signed Integers:** `i8`, `i16`, `i32`, `i64`, `isize` (`i128` excluded) +* **Unsigned Integers:** `u8`, `u16`, `u32`, `u64`, `usize` (`u128` excluded) +* **Pointers:** `*const T` and `*mut T` (zero-sized metadata only) +* **Masks:** 8-bit, 16-bit, 32-bit, 64-bit, and `usize`-sized masks -Floating point, signed integers, and unsigned integers are the [primitive types](https://doc.rust-lang.org/core/primitive/index.html) you're already used to. -The `mask` types are "truthy" values, but they use the number of bits in their name instead of just 1 bit like a normal `bool` uses. +Floating point, signed integers, unsigned integers, and pointers are the [primitive types](https://doc.rust-lang.org/core/primitive/index.html) you're already used to. +The mask types have elements that are "truthy" values, like `bool`, but have an unspecified layout because different architectures prefer different layouts for mask types. [simd-guide]: ./beginners-guide.md [zulip-project-portable-simd]: https://rust-lang.zulipchat.com/#narrow/stream/257879-project-portable-simd |