What is the latest processor in the powerpc family of CPUs?

In 1974, IBM started a project with a design objective of creating a large telephone-switching network with a potential capacity to deal with at least 300 calls per second. It was projected that 20,000 machine instructions would be required to handle each call while maintaining a real-time response, so a processor speed 12 MIPS was deemed necessary. This requirement was extremely ambitious for the time, but it was realised that much of the complexity of contemporary CPUs could be dispensed with, since this machine would need only to perform I/O, branches, add register-register, move data between registers and memory, and would have no need for special instructions to perform heavy arithmetic.