The Lexra story is an interesting one
They cloned MIPS instruction set and worked well untill MIPS Inc. sued them

"I worked for Lexra, a scrappy CPU company, now out of business. The Lexra story is an interesting one, filled with lessons about the business of selling microprocessors and semiconductor intellectual property. I have recently searched the web and found many incorrect statements about Lexra. With this document, I hope to set the record straight."

linux..>..intel..<..amd..~..powerpc