Getting started with Arm Helium: The new vector extension for the M-Profile Architecture

Arm has announced the latest version of the Armv8-M architecture, known as Armv8.1-M, including the new M-Profile Vector Extension (MVE). The vector extension brings up to 15 times performance uplift to machine learning (ML) functions, and up to 5 times uplift to signal processing functions compared to existing Armv8-M implementations. It may be viewed as the Armv8-M architecture’s version of the Advanced SIMD Extension (Neon) in the A-Profile. 

Arm Helium technology is the M-Profile Vector Extension (MVE) for the Arm Cortex-M processor series.

Armv8.1-M architecture new features

• A new vector instruction set extension (MVE)
• Additional instruction set enhancements for loops and branches (Low Overhead Branch Extension)
• Instructions providing half precision floating-point support
• Instruction improving state management of the Floating Point Unit (FPU)
• Enhancements to debug including:
  • Performance Monitoring Unit (PMU)
  • Unprivileged Debug Extension
  • Debug support for MVE
• Reliability, Availability and Serviceability (RAS) extension

Start early software development

Arm tools are developed along with the architecture. They are now ready for lead partners to start developing software and migrating libraries and other code to Helium, to enable performance increases for DSP and machine learning applications. Tools with support include:

• Fast Models for software execution and optimization on a virtual platform
• Arm Development Studio for comprehensive software development and debugging on Windows or Linux for any Arm-based projects
  • Arm Compiler 6 for maximizing code performance
  • Keil MDK for software development and debugging in Windows for Cortex-M and microcontrollers

The Armv8.1-M simple programmer’s model, combined with familiar Arm tools, is a key advantage of Helium. Using a single toolchain for control and data processing, leads to lower development costs and less code maintenance.

Virtual platform with Fast Models

Arm Fast Models provide fast, flexible programmer's view models of Arm architecture and IP, enabling software development of drivers, firmware, operating systems, and applications prior to silicon availability. Fast Models allow full control over the simulation, including profiling, debug and trace.

There is a Fast Model available for lead partners, which can be used for early software development. It is based on the MPS2 Fixed Virtual Platform (FVP). The Armv8-M architecture envelope model (AEM) has been extended via the plugin interface to support Helium. This provides a suitable platform to get started writing and debugging software. 

Code, build and debug with Development Studio

Development Studio featuring Keil MDK (µVision) has added Helium support for software compilation (Arm Compiler 6) and debugging. This includes disassembly and updated register views for new registers in Armv8.1-M. The toolsuite is also available for lead partners today.

Performance enhancements to Cortex-M

Helium, the M-Profile Vector Extension included in Armv8.1-M, brings significant enhancements to the Cortex-M processor range and will enable the use of a single CPU for both control and data processing code. The performance enhancements enable applications, such as machine learning and DSP.

Arm tools have been developed in parallel with the architecture and are available now for lead partners to start developing software on both Windows and Linux. The Helium support in Arm Compiler 6, combined with leading performance and code density, make it a great choice to get a jumpstart on migrating software to Helium. Arm Fast Models combined with Arm debuggers make it possible to run code and see the Architecture Reference Manual in action.  

Further reading

• The press announcement gives a high-level overview of Armv8.1-M and Helium, plus details on the performance enhancements.
• The 'Making Helium' blog offers insight into the creation of Arm's MVE.
• For full details on the architecture see the Architecture Reference Manual for Armv8.1-M.
• The ‘Introduction to Armv8.1-M architecture’ white paper showcases the technical highlights of the new features and is available to download below.

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