ARM Community: 64-bit in Mobile, ARMv8 Preparing for the Future of Computing - ARM Community

With the announcement of the ARM^® Cortex^TM-A53 and Cortex-A57, ARM has announced its most power efficient application processor ever and the most powerful smartphone processor ever. When you buy a Cortex-A50 smartphone in a couple of years it will run all the great 32-bit OSes and apps that you see on your ARM smartphone today, but better. However, your Cortex-A50 handset will also run ARM’s latest 64-bit instruction set, but why should you care?

Frankenstein Architectures Need Not Apply

Before I go into how 64-bit will affect mobile over the long term, I would really like to emphasize how much work has gone into ARM’s 64-bit architecture to ensure that it is fully optimized for mobile.

Rather than taking our present architecture and just doubling it, and bolting on the bits you need to make it 64-bit (The “Frankenstein Approach”), as other architectures have done, ARM did a ground up design. The ARM architecture was designed with the best practices of the late 1980’s (rather than by engineers in flares in the 70’s for another architecture), however since the 1980’s technology has progressed. ARMv8 was a great opportunity to take the world’s most popular processor architecture and make it better using two key criteria:

• It must be simple and elegant so it is energy efficient for mobile
• It must be designed in such a way that it is easy to implement both 32bit and 64-bit instruction sets with minimum overhead.

For those who are pedantically literate, yes I know Frankenstein was the creator rather than the monster (I do have Frankenstein on my ARM Powered Amazon Kindle), so the title should have read “Frankenstein’s Architecture Need Not Apply,” but the original title was snappier.

Proof is in Production

To show how good the ARMv8 instruction set is, let’s have a look at the Cortex-A53. The Cortex-A53 delivers the same performance as the Cortex-A9 that you have in your smartphone today, but it does it with half the power, and is about half the size, plus it has 64-bit support!

One OS, Multiple Screens, Multiple Devices

At the moment, smartphones are shipping with 2GBytes of DDR memory, so you should see handsets with 4GBytes of DDR in late 2013 / early 2014. The large physical address (LPAE) feature of the Cortex-A7 and the Cortex-A15 are already supporting 4Gbytes and beyond.

The reason that you will need 64-bit in the long term is that mobile computing is breaking out of one form factor. Smartphones will be used with multiple screen types from TV’s to desktop monitors, also OS (operating system) providers are using the same core OS and tools across multiple form factors. OS providers will only want to support one version of the OS and tools across this continuum of devices and a 64-bit OS will be required to ensure you can support anything from your smartphone computing experience to your laptop/desktop computing experience.

James Bruce, Lead Mobile Strategist, ARM, is based in Silicon Valley. James is without doubt a gadget guy who is continuously looking at the latest devices and services on them. Working for ARM allows James to see what technology will be on your mobile device in 3 to 5 years time. This view of the future combined with being based in Silicon Valley and having worked on mobile for the last 12 years allows James to have a unique view of mobile technology. At the moment James is enjoying the latest quad core Cortex^TM-A9, quad core Mali^TM-400 smartphone, but is waiting impatiently for next years Cortex-A15 phone.