BARCELONA – Since the introduction of the Apple iPhone 5S with the 64-bit Apple A7 processor, it's become something of a status symbol to have a 64-bit mobile applications processor. Intel, Mediatek, Nvidia, and Qualcomm either announced 64-bit plans before or during the Mobile World Congress here.
While there’s no proof that mobile devices are ready for 64-bit code, the Apple introduction has kicked off a flurry of 64-bit chip announcements that continue through the 2014 Mobile World Congress. The rush to 64-bit mobile processors is on.
Does 64-bit ARM processors make any sense in a 2014 smartphone? Or is 64-bitness the next big marketing check-off box for smartphone chip makers? But will consumers of high-end smartphones be clamoring for 64-bit processors, like the one found in the Apple iPhone 5S? The answers are: somewhat, clearly, and uncertain. In addition, there’s going to be an uneven introduction of 64-bit processors in the market.
The utility of a 64-bit processor in smartphones and consumer tablets has been subject of debate. An executive of one chip company called it a “gimmick,” but soon afterwards his employer disavowed that categorization.
Apple’s 64-bit iOS and application code takes advantage of the more efficient ARMv8 instruction set, but it’s hard to separate the influence of the new instruction set from the other microarchitecture changes that Apple made in the A7 when comparing it with other 32-bit ARM processors.
Intel is also promoting 64-bit support in its latest Atom processors build on the 22nm Silvermont core. But 64-bit instruction sets are not only useful to address larger memory arrays, both ARM and Intel have solutions for paging schemes to support more than 4GB of RAM in their respective 32-bit instruction sets.
In both the ARMv8 instruction set (and to be more exact, the AArch64 mode) and the Intel x86-64 instruction set there are enhancements to the chip microarchitectures that improve performance and break through limitations of the 32-bit versions. The ARMv8 and x86-64 instructions offer significantly more register resources and add new capabilities such as improved virtualization support.
While Apple recompiled its iOS operating system and core applications for 64-bit, neither Google’s Android nor Microsoft’s Windows Phone operating systems are 64-bit enabled. Both Intel and Nvidia have demonstrated Android recompiled for 64 bits, but only not as a released operating system and Google has not announced native 64-bit support.
Microsoft has also not revealed a 64-bit roadmap for Windows Phone OS. The lack of a 64-bit operating system is only a temporary problem as 64-bit operating systems lagged the the introduction of 64-bit capable PC processors and the ARMv8 instruction set include 32-bit backwards compatibility through the AArch32 mode.
Next page: The latest 64-bit SoCs