updated 03:40 pm EDT, Thu October 27, 2011
ARM explains ARMv8 chip architecture
ARM on Thursday outlined some of the details of its first 64-bit chip architecture, ARMv8. The design is an extension of the current 32-bit ARMv7 and either keeps or expands on features like its Neon instructions, security, and virtual machine support. Most of the benefit comes from the move to 64-bit by itself, which lets it handle much larger data sets and support more virtual memory, sometimes leading to faster performance.
Its 32-bit component keeps all the same features and is backwards compatible. An OS could theoretically build in support for legacy apps, although ARM hasn't said if the v8 platform supports running 32- and 64-bit code at the same time.
Partners are already getting compilers to build 64-bit ARM code and are already getting "fast models" to help prototype their work. Few customers have been named, although NVIDIA has pledged its support and is likely to use it for future Tegra chips as well as Project Denver, its desktop-grade ARM chip effort. Microsoft has called ARM an "important partner" and hinted that a 64-bit version of Windows 8 or later was coming.
Details of full-scale processors with ARMv8 are due in 2012, although they may not reach shipping products until 2014.
Pressure doesn't yet exist for ARM to go to 32-bit in smartphones and tablets, where most devices stop well under the 4GB ceiling of 32-bit memory addressing and often aren't performing tasks that would get a significant benefit from moving to 64-bit. As devices become more advanced, however, 64-bit will become a necessity to at least go beyond 4GB of RAM as well as to take on more desktop-level tasks. Apple has been a strong advocate of tablets and smartphones taking over tasks that normally would have needed a traditional computer and may be one of the earliest adopters.