The most astonishing thing about this is it was done under forbearance of the ISA.. PA-RISC ISA was basically frozen in 1996 and they were able to ride that at

The most astonishing thing about this is it was done under forbearance of the ISA.. PA-RISC ISA was basically frozen in 1996 and they were able to ride that at the top for years. For instance PA-RISC doesn't really have appropriate instructions for desirable atomic operations. But it led to working on the right problems, a hardwired control RISCy chip that happened to be philosophically similar to the survivor POWER.