Microsoft has taken a relatively rare architecture license to the ARM chip and that's pretty much all the pair are saying about it.

The details of the deal are "confidential" although ARM broadly hints that Microsoft means to straddle the chip in "multiple application areas."

Speculation has turned to tablets as well as new and improved mobile phones, e-readers, new versions of its Xbox games console, even an ARM-based PC.

Microsoft has had Windows Embedded and Windows Phone on ARM chips for years. Presumably Windows 7 is next.

Microsoft's contribution to the discussion was to say that "with closer access to the ARM technology we will be able to enhance our research and development activities for ARM-based products."

Google and Apple have been making hay with ARM-based devices. Microsoft may want to develop its own ARM chip like Apple for better integration. The license would cover it.

No financial terms were disclosed. The news sent ARM's stock up 12%.