Implement Sum/Product over references

[rust.git] / README.md

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@@ -1,6 +1,50 @@
-# stdsimd
+# stdsimd - Rust's standard library portable SIMD API
+[![Build Status](https://travis-ci.com/rust-lang/stdsimd.svg?branch=master)](https://travis-ci.com/rust-lang/stdsimd)
 
 Code repository for the [Portable SIMD Project Group](https://github.com/rust-lang/project-portable-simd).
+Please refer to [CONTRIBUTING.md](./CONTRIBUTING.md) for our contributing guidelines.
+
+The docs for this crate are published from the main branch.
+You can [read them here][docs].
+
+If you have questions about SIMD, we have begun writing a [guide][simd-guide].
+We can also be found on [Zulip][zulip-project-portable-simd].
+
+If you are interested in support for a specific architecture, you may want [stdarch] instead.
+
+## Hello World
+
+Now we're gonna dip our toes into this world with a small SIMD "Hello, World!" example. Make sure your compiler is up to date and using `nightly`. We can do that by running 
+
+```bash
+rustup update -- nightly
+```
+
+or by setting up `rustup default nightly` or else with `cargo +nihgtly {build,test, run}`. After updating, run 
+```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/stdsimd" }
+```
+
+and finally write this in `src/main.rs`:
+```rust
+use core_simd::*;
+fn main() {
+    let a = f32x4::splat(10.0);
+    let b = f32x4::from_array([1.0, 2.0, 3.0, 4.0]);
+    println!("{:?}", a + b);
+}
+```
+
+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
 
@@ -14,7 +58,12 @@ 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`, `masksize`
+* **Masks:** `mask8`, `mask16`, `mask32`, `mask64`, `mask128`, `masksize`
 
 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.
+
+[simd-guide]: ./beginners-guide.md
+[zulip-project-portable-simd]: https://rust-lang.zulipchat.com/#narrow/stream/257879-project-portable-simd
+[stdarch]: https://github.com/rust-lang/stdarch
+[docs]: https://rust-lang.github.io/stdsimd/core_simd