lowRISC

lowRISC is creating a fully open-sourced, Linux-capable, RISC-V-based SoC, that can be used either directly or as the basis for a custom design. They aim to tape out their first volume chip this year.

Their open-source SoC (System-on-a-Chip) designs will be based on the 64-bit RISC-V instruction set architecture. Volume silicon manufacture is planned as is a low-cost development board.

lowRISC is a not-for-profit organisation working closely with the University of Cambridge and the open-source community.

http://www.lowrisc.org/

>>3
Pre-Pentium patents have expired and IIRC some of the newer ones have expired too. I know for sure the 486 is public-domain. But also keep in mind, "if you don't get sued by someone trying to stop you from competing, you're not trying hard enough."

>>4
It's basically MIPS. Too many registers, horribly bloated and very sparse instruction encoding.

http://bbs.progrider.org/prog/read/1405230133

http://www.extremetech.com/extreme/188396-the-final-isa-showdown-is-arm-x86-or-mips-intrinsically-more-power-efficient

Look at how much cache the MIPS has relative to the x86 and ARM. And yet it still manages to be the least efficient, even after accounting for process variation and clock speed.