ARM's East denies immediate 64-bit chip plans

ARM's assault on the server market with its many-core, low-power designs continues, but the company has ruled out any immediate plans to create a 64-bit processor claiming a lack of need in the market.

When British chip design firm ARM released details of its Cortex-A15 'Eagle' processor, its intention to target x86 rival Intel's lucrative server market was clear. The inclusion of virtualisation extensions, the ability to access large quantities of memory, and improved symmetric multiprocessing support all suggested that this was a chip heading to the server room rather than smartphones.

For those used to the world of x86 processors, however, there was one glaring omission: for all its next-generation server-friendly features, the Cortex-A15 is a 32-bit chip at heart.

The overwhelming majority of modern x86 processors on the market today use a 64-bit addressing system, allowing them direct an immediate access to memory locations above 4GB. All ARM designs, by contrast, stick with a 32-bit address space.

While the Cortex-A15 includes physical address extension capabilities, which allow the chip to access memory locations above 4GB as though it was a 40-bit chip, many saw the restricted address space size as a weakness in the server market and a clear indication of the design's origins in the smartphone and embedded markets.

During the company's most recent earnings call, however, ARM chief executive Warren East dismissed such concerns. "It's logical to suppose that at some stage in the future ARM will extend its architecture in that direction [of 64-bit processors]," East claimed, "and it would certainly be helpful as and when we have those sorts of [large-memory server] products.

"There are certainly server applications today for which a lack of 64-bit is not a barrier," East went on to explain. "A 32-bit processor is perfectly adequate to address multi-core configurations and blades with multiple multi-core chips."

With ARM's core design tactic being low-power chips that can offer far more cores per rack than their faster yet higher-power x86 equivalent, it's clear that East doesn't think a relatively limited address space is going to cause any problems in the short term.