Milpitas-based Phoenix Technologies, a provider of BIOS software for the PC market, said Thursday that it has acquired Touchstone Software Corporation. Touchstone is a developer of computer diagnostics and PC updating technology. Financial terms of the acquisition were not disclosed. Phoenix said that the acquisition would enable it to offer services based on Touchstone technology to PC OEMs/ODMs, SMBs and consumers, as well as incorporate the technology into its own products. Phoenix said it expects the acquisition to close in Q2 of this year.