Introduction to Rust

Rust, a safe programming language

In this Learning Path, you will learn the basics of how to program SIMD code on Arm using Rust.

Rust is a safe programming language with some key advantages:

• It’s a modern, strong-typed language
• Rust is memory safe by design: it’s very difficult to introduce a bug like buffer overflow with Rust
• Strict language: the Rust compiler is very strict and doesn’t let you make easy mistakes as you might with C
• The usage and support for Rust is expanding to many architectures and operating systems

SIMD with Rust

Support for intrinsics in languages such as C and C++ is generally added by the compiler teams of each vendor so, for example, the Arm compiler teams are responsible for adding support for Arm ISA intrinsics.

Rust is a little different in that regard. While vendors are still very involved in providing the support for SIMD intrinsics in the compiler, there are other alternatives and approaches used to provide SIMD abstraction.

Currently there are 2 SIMD programming interfaces in Rust:

• One under std::arch which follows the C intrinsics as much as possible
• Another, std::simd, which provides a portable abstraction to SIMD programming so that code can be recompiled across different architectures with more or less the same results. While there are similar libraries for C and C++, this is different in that the intent is for it to be merged as an official extension to the Rust standard library under std::simd

You will learn how to use both of these interfaces to write code that uses Advanced SIMD/Neon instructions on an Arm CPU.

Before you start, make sure you have the Rust compiler installed .

To check if you have a working rustc compiler installed, run the following command:

    

        
        
rustc --version

    

The output should look similar to:

    

        
        
rustc 1.79.0 (129f3b996 2024-06-10)

    

One of the interfaces you will use in this learning path is std::simd. Support for this feature currently exists only in the rustc ’nightly’ version (one of the release channels for Rust).

Switch to the nightly version to rustc by running the following:

    

        
        
rustup default nightly

    

To check the version again, run:

    

        
        
rustc --version

    

The output should now look similar to:

    

        
        
rustc 1.82.0-nightly (92c6c0380 2024-07-21)

    

Now that you have a working Rust compiler with the features supported in the nightly version, you can continue with building and running the examples included in this Learning Path. The code examples in this Learning Path aren’t optimally written for Rust (to do that you would have to use cargo, find the proper crates to do specific tasks, for example for 2D arrays, which would increase the complexity of this Learning Path significantly).