Microsoft and Google have to date tailored their operating systems to chips made by Intel and ARM Holdings respectively, but yesterday both companies announced they would be supporting the other chipmaker’s products.

Intel announced an alliance with Google, under which mobile OS Android be optimised for Intel’s upcoming mobile chip architecture. Until now, the main chip architecture for Android devices has been ARM’s – its low power chips are suited to the requirements of smartphones.

But Intel said that its Atom range of mobile chip designs will be used in Android-based devices from a number of handset makers in the first half of 2012.

"I’m excited by the possibilities of this collaboration," said CEO Paul Ottellini at the company’s developer conference in San Francisco. "It will enable our customers to bring exciting new products and user experiences to market that harness the combined potential of Intel architecture and the Android platform.”

At a developer conference of its own, meanwhile, software giant Microsoft revealed the next version of its operating system, Windows 8, and confirmed that it would work with processors based on ARM architecture. First discussed earlier this year, this represents a departure from ‘Wintel’ partnership that lasted many decades.

Similarly to Apple’s latest operating systems release Lion, Windows 8 will draw on features from both mobile and PC operating systems.

The backdrop of these announcements is tumbling PC shipments, which dropped 15% in the UK during the last quarter, eating into revenues at Intel and Microsoft. Smartphone and tablet shipments are on the rise however, and currently Android and ARM are the two powerhouses of software and chip architecture respectively.